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removing "snot-like" goo from ABS circuit board- Bluebee pls. read!

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346K views 178 replies 45 participants last post by  Sdavis586  
#1 ·
Bluebee, you may want to add to your outstanding one-stop ABS thread!

After getting my module issues all sorted out, my realtor has a 2000 528 iaT that has the "three lights of death" being ABS,DSC, Brake lights on. I have eliminated the sensors with diode test and he has given me permission to attempt surgery before just ordering him a new module for $480 plus coding. I have the module all dremel-led open neatly and discovered what I thought would be dielectric grease is more likely a snot-like (sorry) condensation preventive "goo" all over the surface-mounted components. It is soft and could be likely wiped away or the area to be re-soldered could be cleared mostly of the clear goo and the connections remelted (I imagine the heat of the solder pencil which I can control down to the degree will sizzle the remaining goo away). I would guess by messing with the stuff a little that rubbing alcohol would likely even make it go away. It looks very mild, but always better to ask and then others see the answer as well. I planned to just move the goo away from the solder points that need renewing and then hoped the heat from the pencil will melt the remaining away...re-do connections and then pull some excess back over the contacts. I believe it is not dielectric grease to dissipate heat, but rather a moisture preventer that keeps any moisture that could form inside the case from getting on the board, causing corrosion or a path of reduced resistance between points that are already very close. I also think a plain, white or clear dielectric grease could be put there after the repair as well instead of Bosch technician snot! I will advise how the repair works. I think the patient has a chance for complete recovery as his issue resets itself every night when the wagon cools and then re-lights the codes after about 10 minutes of driving. Very symptomatic of very common heat-affected solder joints.

Bill
 
#2 · (Edited)
Hi Bill,
It will be great to see the "operation" on the ABS patient!

With luck, goo-be-gone and solder joints resoldered.

Bear in mind, that most forum posts intimate the problem is cracked solder joints (which you can fix); but ATE definitely told me they also replace poor-quality components. I don't know what the problem is ... there have been some autopsies which reveal more solder cracks than component failures.

It will be very interesting to see what you find out.

I wish I had the courage to open mine up but I just didn't have the confidence that you have to split it open and take a peek. I am curious though ... very curious what's inside that is breaking. The rebuilders (ATE at least) apparently don't mind working on already-opened ABS control modules (although in one case it was posted they wouldn't work on it not because it was opened but because it was destroyed too much by the previous technician).

This will be very interesting to see the pure insides of the ABS module with all those cute little components tucked neatly together.

Let's keep an eye on this and a cross-reference link so others can benefit at the click of a mouse!

- cn90 ABS Module Repair Info for E39 (from Volvo forum)
- E39 ABS Module Repair (with high resolution pics at http://conventory.dk/bmw/bmw.zip)
- Volvo ABS Control Unit Repair
- VW ABS Repair (contains the GIF below)

Animated GIF of a solder joint repair ...
1. Remove the gel-like substance.
2. Tin the contact plate.
3. Solder copper wire.
4. Tin the silver conducturs at the place of the maximum distance from the board.
5. Solder copper wires between two silver conductors.
6. Cut the remaining part of the wire.
(from http://passat-b5.ru/remont/abs/abs11.gif)
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#3 · (Edited)
There is a dearth of pictures of the INSIDES of the ABS control module unfortunately ... so this is only the best I could find on the net (some of which are mine but not the ones showing the guts as I was too timid to open it up myself) ...
 

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#4 ·
I wish that I could "take back" some of my posts regarding my experiences with ATE personally. They rebuilt my module and 4 months later when I had problems I had to return it again under warranty. They said it was received in perfect working order. I sent it to BBA who said it failed two of three tests and they returned it at no charge, paid shipping both ways, and did NOT try to sell me another module. They opened it and said it was such a mess that they refused to even attempt to "reverse engineer" it. ATE said that BBA was just seizing a chance to bash them, but they never wrote anything public, refunded 100% of my money as they said it was: a) bad and b) not able to even be considered for a core.

I therefore see no reason to believe BBA took advantage of the situation. ATE said it was good. BBA said it was bad. A new module from EAC immediately cured the problem once it was coded. You tell me who was telling it like it was? I was told I would get my money back from ATE immediately but after two weeks I called Don, the owner, and he wanted my module back a third time and then changed the story to "they do not process refunds for 30 days so that they (ATE) can get their money back for the original Ebay auction that I purchased the ATE service from". I see no way that Ebay should lose their listing fee for ATE's failure to find the problem with my module, do you? This is when I began to doubt ATE at their word. The first time they received my module I had not tested my sensors *ASSuming* the module was bad. They said it was bad when they received it, but were able to repair it 100% good as new. I re-installed it and the errors were still there. That is when I tested the speed sensors. The RF was bad in the diode test. I replaced it and the problem was gone for 4 months. Then, the problem came again and so module went back and this is when they said it was fine. Remember, their warranty work was at stake now.

Obviously it was bad or the new module I had to buy would not have cured the problem. It has been a year now or more. Recall that BBA said it was bad also. YMMV with ATE. At least mine was glued back together very neatly by ATE and not marked with a reman sticker. Don said he worked on my module "himself". I also had to intervene with another forum member who had not gotten his refund after 4 mos. from ATE. I called Don and the guy got his money. Their customer support sucks regardless of their ability to fix modules. I think they may be able to repair a percentage successfully, but some they pass as repaired are still bad and others have had same results with ATE. Have never seen with BBA. Have heard of a module that Module Masters said was not repairable though that BBA was able to fix. For my money, I'd go with BBA and if you catch an Ebay auction right they are no more expensive than ATE.
 
#5 ·
I only went with ATE because they were $150 in toto, including shipping.

Based on your information above, we probably should recommend to newbies:
- BBA
- MM
- ATE

In that order ...

Do you agree?
 
#6 ·
Absolutely agree. Also, the goo may be there to prevent tampering. Now that I have gone through an attempted repair, I can say this... I found a broken wire. The wires are made of a material that is difficult to get solder to stick to. You must remove the goo to get to good copper and wire to renew any solder joints. When you mechanically (for the lack of a better term) or physically try tomove the "goo" even with a q-tip and de-natured alcohol it tears the microscopic gold wires that are as thin as a frog's hair. Nearly invisible except under a large magnifying glass which I used. If I were to attempt another module repair, I would find a substance that can chemically "dissolve" the goo first from the entire board and then carefully renew just the larger silver wires circled in several pictures. Any attempt to remove the goo with heat or by pushing it aside will likely tear one of the gold wires. The module is made purposely hard to work on unless you have played with a few first to learn the game. Those that simply melted a few outside wires were very lucky if they got it to work.
 
#9 ·
540iman said:
Absolutely agree.
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Unless someone pipes in otherwise, we'll go with the order of (1) BBA, (2) MM, and (3) ATE for now. It sure helps as I know you guys' recommendations helped me greatly. You were right from the start ... it just took me nearly a year to believe you. :)

the goo may be there to prevent tampering.
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I'm surprised what is represented as goo in the animated Bosch ABS animated GIF (from a VW Passat) doesn't look like anything. Is the "goo" you speak of the same as the goo they're talking about? If it's there, I don't even see it in ANY of the pictures I posted (do you?).

I found a broken wire.
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So far, only ATE has told me that other components are involved. I wonder if they were telling me the truth. ... Hmmm ...

the microscopic gold wires are as thin as a frog's hair.
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This is a great warning for the next attempted repair!

I would find a substance that can chemically "dissolve" the goo first from the entire board and then carefully renew just the larger silver wires circled in several pictures.
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This is what we need all of us to strive to resolve!

But ... I don't "see" the gel anywhere. Where is this gel???

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#7 ·
I do not have problem with my E39 ABS yet (not yet...:)).

But I have used www.bba-reman.com. Great people with all the Bosch fancy diagnostic tools.
I replaced my 98 Volvo V70 ABS Module (after a long unsuccessful repair!).
$120 with core (ship old ABS Module to them).
Three years later so far so good.
Plus BBA gives you a L.T. warranty as long as you still own the car.
Peace of mind is worth $120!
 
#14 ·
cn90 said:
I replaced my 98 Volvo V70 ABS Module
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Hi cn90,
Your post got me thinking so I did some research on the other makes that used the Bosch 5.3 and 5.7 ABS control module (Volvo, Saab, Audi, VW, etc.)

Notice my summary in this xref post shows all have similar issues with trying to repair the thin gold wires!

I also posted all the relevant pics from http://passat-b5.ru/remont/abs/ into that thread (in this post).

Here's also a repair PDF attached ...

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#8 ·
Yes, I am aware of BBA et al, but was trying to salvage one before going another way. FYI...if you try to move the "goo" with anything mechanical (your finger tip, a fine screw driver or fine pick, you can easily tear the ultra-fine wires in the newer BMW modules. I have seen the pictures of the Volvo module you posted, and the newer BMW modules are NOTHING like that. The silver wires in say a 2000 and up module are small, but large enough to solder. They have a zillion gold wires that are smaller than a human hair yet sit proud of the board. If you try and move or coax the goo out of your way to refresh some of the larger solder joints, you will risk breaking the tiny gold wires. I have a soldering station with an infinitely variable digital temperature selector from 200 degrees F to 899 degrees F and a very fine pencil tip. I used a magnifying glass and the goo will not sizzle away or melt. I believe it must be chemically removed w/o disturbing ANY wires before attempting anything except a crude repair at best. If you can safely remove the goo, the wires circled in most of the depicted pictures CAN be repaired. You must just be damn careful when even pushing that gooey substance around. There is absolutely NO REASON why bosch used such fine wiring except to confound anyone attempting to repair for the first time at BMW engineer's insistance. It is a small circuit board in a large case and the goo is not needed except again...to prevent repair. My passport radar detector is far more complex in the same size package using almost all surface mount technology and there is just no reason to use soft, gold, frog-hair-sized wires to go point-to-point. Another bravo for our German parts salesmen.
 
#10 ·
Yes, I see the gel in the picture and yes...what I refer to as goo is the same thing they refer to as "gel". I would describe a "gel-like" substance to most people to be something on the order of clear, hair gel. It is fairly thin in consistency, possibly runny, etc. I call this stuff "goo" as it is more like the substance that magazines and other items sometimes use to attach another substance not permanently, but so that a user can take something loose later. A gummy, clear, sticky goop that is in the picture, but because it is clear does not reflect well in the picture. Some looks to have been remove possibly by the gold contacts, but is clearly there at the opposite ends of the wires circled with the arrow in the picture. If you look closely at the light reflection in the picture, you can see "something" reflecting light and that would be the gel. It MUST be moved aside somehow to get the solder to flow to the wires and the contact patch where they connect. Solder will not flow through this gel. It is too bad this picture does not show the back side of the board where the hair-like wires are attached. I will try to take some pictures possibly this weekend. There are NO components on this board that ATE can/has replaced. I don't care what they say. With this Bosch module you can't replace anything. On a picture CN90 showed of an older Volvo module, component swapping may well be possible. It is my belief that BMW has gone to great length to make these modules nearly (note I said nearly) impossible for a lay person to work on. After some experimentation, I believe if you found a way to get rid of the goop w/o a mechanical means, you might have about a 25% chance of restoring the module by ONLY re-soldering the larger, silver wires which are still minute and if you heat one end, they are so short you will melt the solder at the other end. You must be light and fast and use the minimum heat setting to just barely melt the solder. In my opinion you have nothing to lose to try, but be prepared in most all cases to buy a new one or send off and take your chances. Sending to BBA will maximize that chance of repair IMO.
 
#11 ·
540iman said:
you can see "something" reflecting light and that would be the gel.
Ah, in the other pictures, it shows more clearly (see below).

You must ... barely melt the solder. In my opinion you have nothing to lose to try ...
Click to expand...
Hopefully when someone sees this cross link when their ABS module goes out, they can try this and let us know the result.

As you noted, for now we'll assume they'll be 25% successful and the rebuilder (BBA, MM, or ATE, in that order) might be the other 50% successful so that gives about a 75% success rate, where your minimum cost is zero and your maximum cost is about $200 USD.

Looking forward to the pics of the undersides!

Image
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#12 ·
My module is very similar to the one shown here, but slightly different. Not much, but this picture depicts well the issue. Look at the row of contacts at the top of the picture..see the eight wires that are easily visible just left of center? Now, to the right of those 8 visible silver wires there are approximately a dozen more contacts visible yet you can not see any wires. Well, at least I can't in your picture but there are the smallest gold wires I have ever seen. Why use gold and then down size the gauge of the wire to the size smaller than a human hair? No, it is not because gold is a great conductor of electricity although it is. I believe it is used because gold, especially pure unalloyed gold is very, very weak. A great conductor as long as you do not disturb it, but totally unnecessary and a waste when a wire is not even needed! Why not just put the contact row on the circuit board itself and use circuit board trace material? To make the unit virtually unrepairable...that's why. Even a small 1/8 watt resistor-sized wire would do just fine. Even the silver wires may be stainless steel or nickel- they are made of an alloyed steel that does not particularly like solder. The wires are almost tack-welded to the contacts. The entire module is an abortion. It is NOT a marvel of electronic ingenuity and I want to see any module where ATE has added components to replace weak ones. Total bull.
 
#13 ·
540iman said:
Now, to the right of those 8 visible silver wires there are approximately a dozen more contacts visible yet you can not see any wires. The wires are almost tack-welded to the contacts.
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This is all very interesting ... and useful.

Are you saying the main problem for others to look for to repair in their modules are for breaks in the dozen or so *****wired contacts to the right of the 8 thicker silvered wires in the photo below?

I want to see any module where ATE has added components to replace weak ones.
Click to expand...
Well, if I had a bit more courage, I'd open up mine so we could take a look ... but I'm too scared to do it unless/until the thing breaks. :(

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#15 ·
Hi Bill,
I did a few more hours of research and found, among the pics already posted in the two threads, the following discussion of gold wires which specifically mentions Bosch ABS ....

http://www******bulletin.org/assets/file/goldbulletin/downloads/P Goodman_1_35.pdf

"Bosch have developed an ABS module which is designed to be fitted close to the engine. This avoids the need for an expensive cable so that the overall cost is lower."

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#16 ·
I'll try to answer in bullet form:
* The Passat module is HUGE compared to a 1999 & up BMW module as relates to size of gold wires and use of conventional/replaceable components such as diodes, etc. ATE can not replace parts on a newer BMW module. I just want to see evidence!
* The gold wires in the Passat picture are at least 3 times the gauge of what Bosch did for BMW. WHY?
* One good reason for using the fine gold wires could be because the wires are soft and fine, they can take vibration better. They are not as brittle- more ductile, but fragile.
* I do NOT believe the problem lies with the gold wires in the purple box, but the larger and more brittle silver wires. In order to remove the goo to get to the silver wires you must be EXTREMELY careful not to disturb the nearby, ultra-fine gold wires which will break if the goo tugs at them as you try to move the goo off of the silver wires which are the culprits. This is why I say the goo would be best dissolved off in some manner to not tug or disturb these fine gold wires. You would basically dip the board probably in a mild solvent that would clean the board of the goo, but not disturb the wiring.
* The discussion of the "hybrid" circuit and "pitch" refers to how small you can make the spacing between each contact point. This is TOTALLY irrelevant in this module as space is NOT an issue. The only reason that I believe Bosch uses both the larger silver wires and the hair-like gold wires is due to current-handling capability. The current that the gold wire can handle is extremely limited so it can be smaller and present the unit as virtually irrepairable by a lay person in most cases. Using copper wiring on ALL point-to-point wiring would be cheaper, stronger, allow more vibration and heat to be absorbed without breakage and would allow the modules to be rather easily repaired. BMW does not want this. Look at how many parts they use that have built-in breakage issues..any of the plastic tubing from W/W pumps, grommets to seal W/W pumps, all plastic components must age, get brittle, and snap (radiator, headlight snaps, et al). Consider what BMW part sales would do if they used a different type plastic or even rubber. Why do you think BMW molded plastic pieces are so high priced in the first place? Radio and instrumernt cluster pixels, etc. They all had design life taken heavily into consideration. They were carefully designed to fail after generally the warranty period has expired, yet many just don't even make it that long. This is the price they pay. They just back-charge the manufacturer on these early failures anyway.

* Last and most to you question BlueBee is NO, the gold wires in a BMW module are nothing like the gold wires in your passat picture. These wires are large and stiff enough to be formed into the inverted "vee" shape you see soldered to the Passat board. In a BMW module, the gold wires are so fine that they just lay in a lazy "S" shape flat to the board virtually. They do not even have enough strength to stand up like that on their own. Any movement of the goo to get at the gold wires will almost certainly break them. Again, I will try using the wifes digital camera with her zoom lens to show how fine they are on the module I attempted to work on. One should *ONLY* attempt to repair the silver wires circled in your pictures and only by making 100% certain when you get to the last silver wire which then has a gold wire for a nextdoor neighbor that you pull only the goo at the silver wires contact patch leaving the goo at the neighbor's house undisturbed!.

Hope this clarifies some Bill
 
#17 ·
540iman said:
ATE can not replace parts on a newer BMW module. I just want to see evidence!
Click to expand...
After looking at all the Bosch ABS autopsy pics I can find on the Internet, I'm ever more strongly tending to agree with Bill (although ATE told me otherwise).

I'm beginning to agree ATE is most likely just replacing the thicker silver-color (aluminum?) (power wires?) and testing the unit before shipping it back to us.

The gold wires in the Passat picture are at least 3 times the gauge of what Bosch did for BMW.
Click to expand...
OMG! The Passat Bosch 5.3 guys said those wires were difficult; I can imagine what the gold wires would be on our Bosch 5.7 BMWs then. Luckily, as Bill noted, the gold wires aren't generally the initial culprit.

In order to remove the goo to get to the silver wires you must be EXTREMELY careful not to disturb the ... gold wires
Click to expand...
I think Bill hit upon the key problem for us to resolve which is how to remove the gooey gel without breaking the gold wires!

the goo would be best dissolved off in some manner to not tug or disturb these fine gold wires.
Click to expand...
This summary agrees with you. But what chemical will dissolve the gel?

allow the modules to be rather easily repaired. BMW does not want this. Look at how many parts they use that have built-in breakage issues..
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I don't doubt you Bill, for a second. I already have been the victim of BMW's poor choice of materials in the headlight adjusters, pixel tape, windshield molding, ABS control module, trunk loom, vapor barrier glue, seat cover paint, cd cover wood, etc., and vanos seals and radiator explosion are in my future, all due to BMWs very poor choice of materials.

the gold wires in a BMW module are ... do not even have enough strength ... Any movement of the goo to get at the gold wires will almost certainly break them.
Click to expand...
I think Bill summarized the problem set and solution pretty well, which I'll tie to the summaries in this post to make the following repair observations:

(0) The main problem appears to be a couple silver-colored (aluminum?) power wires, which apparently break. If you fix these, without breaking anything else, you win!

Note: The problem does not appear to be poor-quality components; it's just wires.

(1) Your first (relatively easy) challenge is to open the ABS module w/o getting too much dust sticking to the gel-like goop so a knife and hammer are sometimes recommended over a Dremel tool and/or hacksaw.

(2) Your second (much harder) challenge is to remove the gooey goop covering the silver-colored wires WITHOUT disturbing the nearby gel-covered gold wires. For this, an as-yet-unknown solvent is suggested as mechanical cleaning often breaks the gold wires!

(3) Your third (relatively difficult) task is to solder a replacement wire for the broken wire; for this, most seem to use tinned copper with flux. The danger here is overheating might destroy chips and lift the *****colored contact pad.

(4) If you've gotten this far, your fourth (relatively easy) problem is to test the unit in the car before you seal it back up. For this, it seems the Russians tape the cover 90% back on and re-install the ABS module in the car to see if all systems are go.

(5) If all is well, your fifth (fun part) problem is to hermetically seal the unit up; I think most simply use an expoxy to seal the case (they can't do much worse of a job than ATE did on mine if you've seen the pictures).

(6) Your last (really fun) part is to write it all up for everyone here to test out on the NEXT inevitable BMW Bosch 5.7 ABS unit that fails!
 

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#18 ·
Bluebee: Where you find these corroborating posts is incredible work! The whole Russian thread makes me feel better as they virtually echoed my *guesses*. The silver wires are steel I believe rather than aluminum. I can verify this with a magnet, but it really matters not. Aluminum melts around 1200 degrees F and I doubt they are aluminum, but possibly stainless or a dual alloy steel (high chromium generally). Point is, solder does not like it. I heartily agree that a conductive epoxy would be the cat"s azz. Denatured alcohol softened the goop quite a bit...I'm guessing acetone, mineral spirits or tri-chlor III will dissolve it. I will test this weekend and try to get a picture of how fine these BMW wires really are compared to the VW. BMW is actually quite brilliant at their choice of materials once you accept that they are out to force the after-warranty owner to buy lots of expensive parts to keep them in business. :thumbdwn:
 
#19 ·
540iman said:
The whole Russian thread ... virtually echoed my *guesses*.
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Yup. I had read your guesses first; then when I read the threads for the audi, vw, saab, bmw, etc., I too felt like you all were agreeing on almost every point.

That allowed me to write up the main steps in the previous post (by summarizing what you guys were all in agreement on).

The ... wires are steel ... solder does not like it. I heartily agree that a conductive epoxy would be the cat"s azz.
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I've never heard of steel wires but whatever they are made of, universally you guys say it's hard to solder (plus heat causes damage to other things on the board).

I wonder if the Russian-recommended epoxy would work?
Mouser Electronics P/N 590-8331-14G $23.95

acetone, mineral spirits or tri-chlor III ... will test this weekend
Click to expand...
It seems imperative we find a solvent that dissolves the goop. Please let us know the results!

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#20 ·
I would heartily endorse any non-heat method of attaching and any technique that requires melted solder. The Mouser product looks IDEAL.

For someone with a metallurgical background I just said steel to get people off aluminum. It *could* be stainless steel. It is likely a highly alloyed steel. Ni-chrome wire gets it's name as it is mostly nickel and chrome and it gets red-hot when heated, but does not melt or lose shape (like in your toaster). Steel is a lose term meaning it has some iron ore base, but it can be full of neat and pricey alloys in tiny amount necessary to do the specific job. Your stainless cutlery that never rusts in your dishwasher or left in your sink (especially a bachelor's sink...weeks) without rusting is close to 304 stainless or what used to be called 18-8 stainless to reflect chrome and nickle percentage content. Flux is a substance that I use to help make the solder flow to te joint as it reacts with the metal and takes off oxides etc. that impede solder from sticking. There are just too many downsides to using heat in this case. It easily can "bridge" across two contacts shorting them and then being difficult to remove without a solder wick or solder-sucker. Any thing that can be applied from a syringe-like applicator would be great. This topic WILL get solved! Unfortunately like any new surgery, you may lose a couple patients on the table perfecting your technique. I wholeheartedly recommend BBA. The risk/reward is just not there for most. By the time you assemble all the products necessary to do the job, why not let someone who does heart replacement a thousand times a day do the surgery(BBA)? However, for those die-hard DIY'ers, go for it forewarned and prepared and far better off for BlueBees diligence for which I note she has accepted nor expects any praise. He doggedness has made these kind of thorough, one-stop shopping assemblies of all info good and bad possible in one place. BBA rocks in my book and always will.I commit to answering what will remove the goop and a good picture of the size of what you are messing with in the BMW gold wires. Good work BB. Take the award. Bill
 
#21 ·
540iman said:
I endorse any non-heat method of attaching ... It is likely a highly alloyed steel... a syringe-like applicator would be great. This topic WILL get solved!
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With persistent guys like Bill and cn90 out there, I'm also convinced we *will* solve the remaining problems. Just like open-heart surgery, we need to all pitch in to add whatever ideas we can ... and the bold at heart will try out the ideas on the next failure!

The two most important techniques to solve are:
I. How to debride the encapsulating gel (w/o breaking gold wires).
II. How to connect the broken alloy wires (w/o lifting gold pads).

The most promising suggestions appear to be:
I. A solvent to dissolve the gel (i.e., gold wires remain undisturbed).
II. An exposy to connect the alloy wires (i.e., no collateral heat damage).

To help out where I can, I researched all known procedures and suggested gels/epoxys to combine all the good ideas I could find into this new tentative open-heart surgery procedure (please criticize so it improves):

(0) The main Bosch ABS 5.3/5.7 failure appears to be a small number (1 or 2?) of silver-colored (steel?) power wires which apparently break off at the (ultrasonically tack-welded?) pad connection.

If you reconnect the wire to the pad, without destroying anything, you win!

(1) Cover and tape the underside of the ABS so that the hydraulic-unit connections are not damaged or contaminated with dust and grit.

(2) Your first (relatively easy) challenge is to open the ABS module w/o getting too much dust sticking to the (silicone? urethane? thermally conductive?) gel covering the electronics; so a knife and hammer are recommended over a Dremel tool and/or hacksaw. Now tape the just-opened ABS module shut again. Yup. Just leave the quarter inch you'll be working on open. This is to protect the rest of the delicate board.

(3) Your next (relatively easy) task is to locate the broken wires. It will most likely be the silver-colored (steel?) wires for power to the board. Some suggest using a sewing needle to "push" the wires to test if they move from the pad which is apparently where they break. Everyone says ionly the silver colored wires will initially be broken; the gold wires will all usually be intact.

(4) Your prepatory (PITA) challenge is to remove the gel covering the silver-colored wires WITHOUT disturbing the nearby gel-covered gold wires. To dissolve the gel, alcohol or acetone or mineral spirits or trichlor III have been suggested.

(5) Your main (relatively difficult) goal is to overlap a replacement wire for the broken silver-colored wires. The danger is overheating might destroy chips and lift the gold contact pad and that the soldering process may disrupt the delicate gold wires.

So, you'll probably want to go with an conductive epoxy such as Mouser Electronics P/N 590-8331-14G $23.95 or Lord "Thermally Conductive Adhesive MT-220".

(6) If you've gotten this far, your next (relatively easy) task is to test the unit in the car before you seal it back up.

(7) If all is well, your penultimate (almost done) problem is to hermetically seal the unit up; I think most simply use an expoxy to seal the case from the elements. See Lord "Epoxy Lid Seal Adhesive EP-870" and "Silicone Lid Seal Adhesive SC0242".

You might also want to add Lord Silicone Encapsulants, SC-300M, SC-316, or SC-319 or Lord Urethane UR-312 gel if you've removed a lot of the original gel.

(8) Your last (really fun) task is to write it all up for everyone here to test out on the NEXT inevitable BMW Bosch 5.7 ABS unit that fails!

(9) If it still fails, then consider sending it out to BBA, MM, or ATE in that order to rebuild it. They've all stated they'll work on most units, even those previously opened up if it passes their acceptance testing.

(10) If it's unrepairable, then consider buying a rebuilt ABS module from one of the sponsors; it will need to be coded at the BMW dealership for your VIN.

(11) Or, consider purchasing a new ABS module, again, from one of the sponsors. It too will need to be recoded at the BMW dealership for your car.

(12) Lastly, drive the car until all the warning lights go out. If you plan on smogging the car, make sure you clear the P0500 "speed sensor" code which always lights when you remove the ABS module.

Note: The attached 2-part PDF (Adhesives, Coatings and Encapsulants Electronic Materials Training) is a must read for anyone looking for materials to remove the gel, to expoxy the wires, and to replace the removed gel!

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#23 ·
bmw_n00b13 said:
no chance that BMW/Bosch can't solve these problems. They're simply making sure that we buy new vehicles and/or parts.
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I have to agree with both of you, although I usually attribute to laziness what you're linking to knavery.

The fact that Bosch 5.3 and 5.7 ABS invariably have this broken-wire hard-to-fix problem in not only our beloved BMWs, but also Audis, VWs, Saabs, etc., worldwide, for many years tells us they just don't care.

They COULD solve the problem in a second; but they don't bother. Makes me sad to think they really don't care to make quality cars. I wonder if any BMW/Bosch Engineers read this forum and cry?

As for the goop, I'm not sure it was done with sinister intent. From reading this PDF, I get the idea that the gel is a silicone or urethane (I wouldn't know how to tell which from the pictures) "encapsulation", which is apparently common for electronic components which need heat dissipation.

Interestingly, the other PDF I referenced shows that BMW felt proud of themselves that they located the ABS in the engine compartment "to cut costs on harness wiring"!

It's all very sad to not be an engineer yet to plainly see absolutely stupid (yes, some say sinister) decisions made by the BMW engineers. I wonder if they're as stupid as they appear but they can't be ... so there must be some other reason for the horrendous decisions that are never corrected.

Maybe you're right ... they don't fix it because they're making too much money off the engineered-in unreliability ... but it doesn't make me wanna buy another BMW real soon ...

My 2 ¢
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#24 ·
When you compare the circuit board size to the module case size, you realize this is in no way a space issue. They really could have designed this module quite easily with NOT ONE SINGLE JUMPER WIRE! You use point-to-point wires when you have components that you want to allow for change-out. Not one of the tiny gold wires or the just slightly larger silver wires are necessary. All could have been placed on one board with no need to jump electricity from point A to point B with a wire that is ultrasonically tacked to the contact points rather than a conventional solder bath assembly method or just surface mount the entire assembly and be done with it. BMW is really not that "stealthy" about how they designed-in part breakage. They actually went out of their way and spent a few coins unnecessarily to make sure certain items break. They PAID money to make certain items weak. Don't get me wrong, where it matters, they have made a superb vehicle. We all agree that a vehicle simply employing crap parts would not be of the level and stature of this brand, but the part sales thing is incredible. I must assume that those in the know at BMW knew from day one that the division could not compete and exist without part sales partially off-setting new car prices and their ability to compete as a viable alternative to
M-B, Saab, Volvo, etc. I would be very curious to take this thread another way and ask those who have owned these other European cars if they too have the same degree of built-in weakness for no reason other than to make it pat the warranty period and then sock it to the "come lately" like myself. You must consider the whole picture of profits and losses.

What this means in the bigger picture is that the BMW does not present itself as a good choice as a used vehicle to buy for those who have fairly inflexible financial resources, but then again BMW never aimed themselves at this financial "stratus". Forces one to be very proactive in their maintenance discipline (good thing in any case) and a willing DIY'er which is after all..why most of us are here.
 
#25 ·
If it makes you feel any better, they relocated the ABS module after he E39 production to an area still in the engine compartment, but out of the heat zone from the exhaust manifolds. I don't see how you could put the ABS module anywhere BUT in the engine compartment...otherwise you would be bringing high pressure brake fluid/ATF fluid into the occupant area. They may have stated they were proud of themselves for placing it in the engine compartment, but I don't see this as any major accomplishment. The fluids are there, the safety issues relative to the occupants says it needs to be there, I don't know of any other vehicle that has it located anywhere else, and wire is cheap!. They just put it in the wrong place without adequate heat shields. I believe BMW has and always will have the price pressures where they must sell parts. They are offering extended warranties and more "free"service" to combat the reputation they have of being problematic and they likely have an agreement with their suppliers who are under tremendous pressure to sell to BMW that parts that don't last through the warranty period BMW now grants will be replaced to BMW free of cost and BMW will eat the labor for the design risks they impose on the design of their components. The Japanese are stressing long life parts,but their engineering is "suspect" as they copy too much without fully understanding the rationale of why the Germans/Americans/Swiss do what they do, but their parts generally have longevity first and foremost.
 
#26 ·
540iman said:
BMW knew from day one that the division could not compete and exist without part sales partially off-setting new car prices
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Well stated! It's a strategic decision, not stupidity.
- Sell a great driving machine at a competitive price
- Add lousy parts (mostly where it doesn't count)
- Make money off the lousy parts replacement business

If it makes you feel any better, they relocated the ABS module
Click to expand...
It does! Really. It always bothers me when I see styupid engineering decisions - especially those not fixed immediately!

I don't see how you could put the ABS module anywhere BUT in the engine compartment
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Well then, maybe we need a new thread on heat shields! (Yes, I saw your excellent post asking the guy to change his title and do some homework and post results back in this thread.)

The Japanese are stressing long life parts
Click to expand...
Oh how I miss the reliability of my Lexus!

BMW just put the ABS in the wrong place without adequate heat shields.
Click to expand...
Later, after I do some research, we can work on a ABS prophylactic thread on the best user-submitted designs for heat shields!

HYPOTHESIS FORMATION:
I've never seen the inside of MY ABS board, nor what ATE did to it, but, is my understanding correct that, in most cases, one silvered-steel-alloy power wire is lifting from its bond pad?

If so, is our hypothesis that the engine heat and vibration are causing that (perhaps ultrasonically tack-welded) power wire to lift off its bond pad?

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#27 · (Edited)
I want to go back to the days of the W124 and the stories I've heard of Volvos that go forever. My grandfather had a '87 300TD that started like a gas engine despite its >450,000 km, and the autobox was just beginning to show its age. It's possible, and BMW could do it if they hadn't been working so hard on associating BMW with throw-away cars from the mid-90s on.

If we figure out a solvent for this gel stuff (someone with chemeng background wanna try?:D), it sounds simple to repair the problem with that conductive epoxy posted earlier.

A more advanced solution, provided we had a solvent, would be reflowing the solder in an oven.
 
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#30 ·
bmw_n00b13 said:
A more advanced solution, provided we had a solvent, would be reflowing the solder in an oven.
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Heat not good. Heat bad. Bad heat.

While I was researching why they use steel wires (you're right ... see this reference postulating why the steel wires in Bosch ABS!)... it's because, they say, Bosch can resistance weld them (whatever that is) without causing heat to the rest of the components. (One way to tell might be to magnetize a needle and hold it against the wire to feel the attraction ... assuming ferro-magnetic steel is used.)

Point is, heat is bad.

I think anything that stays away from heat will be better ... i.e.,
(0) Use a needle against the steel wire see if it moves off the bond pad
(1) Dissolve the (urethane? silicone?) gel with a spot solvent.
(2) Glue the steel wire back to the bond pad with a conductive epoxy.
(3) Replace (if desired) the removed presumably heat-conductive gel.

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#28 · (Edited)
Yes, exactly. One (or more) become intermittent due to vibration, heat, and the fact that dissimilar materials expand and contract at different rates. Aluminum expands considerably more than steel - just for instance- with changing temperature. Same principle applies to non-metallic parts such as the circuit board itself.

We must not lose sight of the fact that the components themselves fail due to heat and poor or intermittent solder connections are not the only mode of failure. The various semiconductors can become heat sensitive and so forth and these are likely the percentage that BBA, MM, & ATE return as "unrepairable". The solder connections are simply a common failure and the only one that a lay person may be able to address themselves- or BBA for that matter, but I can't say for sure that many of the older or non-BMW modules cannot be repaired by a re-builder at the component level assuming that the boards have regular components like diodes or resistors/transistors that are soldered on in a conventional manner. The Vovlo picture CN90 posted is an excellent example of a Bosch module that would appear to be repairable at the level of replacing some components. I tried to take a picture of my module so that you can see the size of the gold wires and they simply do not show up even using a close-up lens on our digital camera. The only purpose it would serve is by showing you what you CAN'T see which would give you an idea of just how tiny we are talking about. With my reading glasses on I can't see them.I can only see them with readers on and looking through a magnifier.
 
#32 ·
Unless my reading comprehension is gone, I don't see any mention of Electrical Contact Cleaner (ECC) as a method of removing the "goo" from the contacts. If it was mentioned, I apologize for the oversight. I've used ECC for many electronic/electrical repairs with great results. I can't say for sure that I've ever applied it to a urethane based protectant but it's worth a shot. I understand that we are concerned with an extremely small area of real estate on the PCB where the contacts lie but if the cleaner was applied with a small soft artist's brush (after dispensing some into a small vessel such as a clean steel jar lid) it may do the trick. The force at which the solution leaves the spray nozzle may be too harsh for the delicate wires.
 
#34 · (Edited)
In another Bosch autopsy, the 2005 Range Rover driver felt one of his teeeny tiny gold wires flopped over.
Here is his post, reproduced below (grammatical errors corrected):

"I took the ABS unit out and pulled the cover off the circuit board and looked at it for about 10 minutes... Either I have bad eyesight or those wires are ridiculously tiny. Anyway I resorted to a magnifying glass and it appears in one spot Bosch missed the snot-like glue around a single gold wire, this wire was lying over extremely close to another gold wire... I went in with a needle and tilted it back upright. If that doesn't fix it I'm going to pull it again and take a million macro shots of it to examine the quality of connection points. Although the fact it was lying over so far might explain this issue. I'm sure once the engine is up to temp that wire must move and bridge to the connection it was closest to when laid over. I'm hoping this fixes the problem, in which case I will pull the unit again, silicone the gold wire into place, then seal the cover... Currently it's just taped on."
 
#38 ·
540iman said:
If you are very, very quiet....you can hear a BMW engineer being whipped as you read this
Click to expand...
Oooh. May I watch!

Here is another recent fix, described today, of the ABS control module.

"To solder "suspect" cold solder joints I employed the use of a 1/2" glass tube to pass through the insulating media then drew out the interfering portion allowing me clear access to the bad solder joint. A little flushing with a Q-tip saturated with acetone and then pinpoint soldering through the glass coffer dam using this http://www.americanbeautytools.com/v2/models/rs/98. As previously mentioned elsewhere in this forum / thread, the usual suspects are the larger edge-board connections. "
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#42 · (Edited)
What you have so well illustrated is what a normal ABS module should look like when BOSCH has not received instructions from a major customer to design a module for them that will be virtually impossible to repair in the aftermarket industry or by DIYers. As you can see, space for the Bosch BMW module can in no way, shape, or form justify its design and construction due to space limitations or anythig like this. I am not saying the last poster's module can readily be repaired by an average DIYer either, but you see no goo and no 50 gauge ultra fine cat whisker wires that are soldered with robots using materials that regular 60/40 solder will not melt to. Any module can fail for a zillion reasons, but to build-in failure by using wires only seen through a microscope is fully a well-thought-out design by engineers instructed to sell parts-and lots of 'em. Oh, and did I say "make 'em expensive"? Anyone who thinks otherwise is simply never going to believe BMW has parts as the answer for selling vehicles into a market that otherwise will not support a normal profit without such antics.
 
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