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Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E39 (1997 - 2003)

E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

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  #26  
Old 03-03-2008, 10:23 PM
Ben Carufel Ben Carufel is offline
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Interesting. Program manager. I should have guessed .

Regarding your ceramic vs. semi-metallic pads question, here are a few useful links:

http://www.tirerack.com/brakes/tech/....jsp?techid=88

The following thread will keep you busy for hours:

http://forums.nasioc.com/forums/showthread.php?t=168098
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  #27  
Old 03-03-2008, 11:04 PM
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Ceramic wins over semi-metallic on all counts!

Quote:
ceramic vs. semi-metallic pads
http://www.tirerack.com/brakes/tech/....jsp?techid=88
Interesting! Shocking really. According to that article, what people said on these forums was all wrong.

SEMI-METALLIC: "OE" (original equipment)
CERAMIC: After market
REALITY-CHECK: TRUE, the Jurid 187s & Textar T4071 OEMs have steel strands to provide strength and conduct heat away from rotors but also generate noise and are abrasive enough to increase rotor wear, according to the quoted article.

SEMI-METALLIC: Very slightly cheaper (but only by a couple of dollars)
CERAMIC: Almost the same price (at least at Europarts & Pelican Parts)
REALITY-CHECK: TRUE, based on my price survey today at a half-dozen recommended BMW parts suppliers.

SEMI-METALLIC: Not as fade resistant (but then again, I don't race)
CERAMIC: Fade resistant so good for frequent high speed braking)
REALITY-CHECK: TRUE, the ceramic pads' copper strands conduct heat away from the rotors even better than the steel strands of the semi-metallic pads, according to the quoted article.

SEMI-METALLIC: Softer so longer-lasting and better on the rotors
CERAMIC: Harder (I'm guessing) so may "chew" up rotors (I read that)
REALITY-CHECK: FALSE. Surprisingly, ceramic pads wear less than semi-metallic pads on both the pads and rotors according to the quoted article.

SEMI-METALLIC: Dusty (I read that somewhere)
CERAMIC: Less dusty (but what has that got to do with braking?)
REALITY-CHECK: TRUE. The ceramic pads generate less dust than semi-metallic pads, according to the quoted article. In fact, the article goes on to state the ingredients in ceramic compounds produce a lighter colored dust that is much less noticeable and less likely to stick to the wheels. Consequently, wheels and tires maintain a cleaner appearance longer, says the article.

SEMI-METALLIC: Quieter (I'm guessing based on what EuroParts said)
CERAMIC: Noisier (again, what has that got to do with braking?)
REALITY-CHECK: FALSE. Surprisingly, ceramic compounds provide much quieter braking because the ceramic compound helps dampen noise by generating a frequency beyond the human hearing range, according to the quoted article.

Wow. I never would have thought that, for the same price, the ceramics would win on almost all counts! I wonder why semi-metallic is even sold anymore?
About the only place ceramics lost out was on "heavy loads" as witnessed by this quote in http://www.aa1car.com/library/ceramic.htm which said:
"Ceramic pads are NOT recommended to replace semi-metallic pads, especially on larger, heavier vehicles. On trucks and large SUVs, semi-metallic linings are typically needed to handle higher loads and braking temperatures."

Oh oh. After all that. It then says not to use Ceramics in BMW cars as semi-metallic was OEM! Sigh.

Can't we get the same answer twice, even out of a single article?

http://www.aa1car.com/library/ceramic.htm
http://www.aa1car.com/library/2004/ic10422.htm
http://www.aa1car.com/library/brakefix.htm

Last edited by bluebee; 03-03-2008 at 11:23 PM.
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  #28  
Old 03-04-2008, 08:38 AM
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Just got off the line with Mark at Zeckhausen and Kevin at Turner Motorsports who were the recommended east-coast suppliers who went home by the time I called them from California yesterday.

Basically, according to Mark at Zeckhausen (and a few articles I read), it seems the word "Ceramic" is merely a friction-material marketing term, not to be relied upon for anything concrete. For example, mud is ceramic (more accurately, clay), so if they dab that as 1 of the 40 components, they can legally market the pads as CERAMIC. So, Zeckhausen says the term is meaningless, preferring to sell them as "Axxis Deluxe" as the low-dust choice instead of "ceramic", which it says on the box. Likewise, Zeckhausen describes the "Axxis Ultimates" as the "ULT", describing them as higher bite, a bit more dusty, and less expensive by a huge margin of $40 per set.

Since the Axxis MetalMasters or Axxis Ultimates seem most recommended (Axxis Ultimates being $16.60 more per set at Turner Motorsports), I'm leaning toward them for now. Likewise, the argument for slotted vs drilled at Zeckhausen (where the pad swells up into the slot providing more bite) is interesting (the tradeoff here being $25 per rotor).

But, there's much more learning to be had so please correct any errors I make as I'll make plenty until I figure this out on my spreadsheet.
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  #29  
Old 03-04-2008, 09:01 AM
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(I'm a Systems Engineer so I understand Program Managers. Bluebee! )
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  #30  
Old 03-04-2008, 12:27 PM
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Quote:
Thanks for the popcorn!

The system engineer has the "big picture" while the program manager has the "deadline responsibility"; neither can, in and of themselves, get the job done alone (much like what happens here in this bimmerfest site where the "team" pitches in on each task).

Part of pitching in is collecting, in one spot, the necessary details to perform a decent brake job (which is what I'm attempting to accomplish in this thread).

To that end, one set of specs I couldn't find in *any* single location were the range of recommended torque settings for the specific bolts involved in a typical brake job (replacing pads, rotors, sensors, & bleeding).

Since I manage missing pieces for a living, I may as post my spreadsheet here as a bimmerfest exclusive!
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  #31  
Old 03-04-2008, 12:58 PM
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la528it la528it is offline
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My bet: In spite of all this planning, you will oversee something, and your brake job will be as successful as that done by someone with zero planning.

What are mechanics? Mechanics are people that know what to do when things go wrong. They improvise tools, and use their experience to help them out of difficult spots. With all due respect, I think you are wasting your time. You would learn more and become better at tooling if you just go ahead and get your hands dirty, because as you say, this job as all jobs, will not go off without a hitch. I just make sure I have the parts, and a rough idea of what to do, and then start... trusting that folks here will help me out of a bind... to each their own
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  #32  
Old 03-04-2008, 02:30 PM
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Quote:
Mechanics are people that know what to do when things go wrong.

Well, a *lot* will go wrong if anyone follows the tutorials that are referenced in this thread!.

Lots of stuff is missing from the Bentleys too!
(like the specification chart all in one spot), and some of the information in these threads is just plain wrong ... so I'm trying to collect the generally-considered-correct procedures all in one place.
To that end, here is my fluid plan that others can follow should they wish to make fewer mistakes.

As always, if there are mistakes or goodies to add, please chip in.

Recommended Fluids:
- DOT 4 ATE 200 low-viscosity flue (or non-DOT4 ATE 400 Super Blue)
- Brakeclean spray or isopropyl alcohol
- Brake-disk quiet or anti-squeal compound
- Never seez compound
- WD40 penetrant

Not-Recommended Fluids:

- Synthetic high-temperature disc-brake grease
- Locktite blue

Recommended Procedures:
1. Do not use locktite on any thread during a brake job as this will drastically change the torque results, potentially causing warped rotors or worse.

2. Do not use anything other than brake cleaner or isopropyl alcohol on the 7 mm caliper guide bolts (e.g., don't listen to those who say grease these bolts with high temperature grease).

3. Use WD 40 if you must, to free up stubborn bolts, especially the 8mm allen-head rotor-to-hub bolt.

4. Do not use brake cleaner on the plastic plugs covering the 7 mm caliper guide bolts! This will destroy the plastic.

5. Likewise, do not put anti-squeal compound on any rubber component as they will swell and deteriorate.

6. It goes without saying to keep the friction material clean of grease and to clean the rotors with engine degrease spray and then with brakeclean spray or isopropyl alcohol.

7. Clean the hub with the wire brush. Then place a dab of anti-seize compound (BMW Never seez P/N 83-23-9-407-830) on the rotor hubs so they can be removed more easily in the future. Do not put anything (not locktite, not anti-seize) on the 8 mm allen-head rotor-to-hub bolt or any bolt!

8. Clean the caliper slides where the ears of the pads slide with the wire brush.

9. Apply CRC or Permatex Brake Disc Quiet or BMW Anti-Squeal compound to the caliper contact face taking care not to get any anti-squeal compound on the rubber dust sleeve.

10. Apply CRC or Permatex Brake Disc Quiet or BMW Anti-Squeal compound to the two brake pad rests on the pad carrier.

11. Do not apply CRC or Permatex Brake Disc Quiet or BMW Anti-Squeal compound to each brake pad backing plate! Never apply high-temperature grease to the brake pad backing plate. Also do not apply synthetic high-temp grease to the pad actuating areas. Read the Bentleys!

12. Top up the master cylinder to the MAX marking with DOT4 ATE 200 (Amber) DOT4 low-viscosity only fluid. When flushing, you can alternate with non-DOT4 ATE 400 (aka Super Blue) low-viscosity fluid (make sure it says so on the label as all DOT4 are apparently not alike). Note that only clear'ish fluids are actually DOT4 despite the specifications. If it doesn't say "low viscosity" on the label, then the Bentleys suggest you not use it even if it is DOT4.

Last edited by bluebee; 03-04-2008 at 02:35 PM.
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  #33  
Old 03-04-2008, 04:50 PM
oconnmic@hotmai oconnmic@hotmai is offline
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Interesting Thread Bluebee

Bluebee, I have to admire your tenacity and attention to detail. The only thing missing is a PERT chart.

I'd also like some input from those following this thread. Do ceramic, metallic or semi-metallic pads wear out rotors faster than organic? Will cheap pads just wear out faster or do they present safety issues such as overheating and warping rotors or some type of catastrophic failure?

For my 528i, the BMW dealer quoted me $130 for the front pads. They said they are organic pads, dirty but work well.

AutoZone has Duralast, semi-metallic for $24. How can this be? The price makes me suspicious that they would not be safe or last more than 10,000 miles. But they do have a lifetime warranty.

Any suggestions?
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  #34  
Old 03-04-2008, 05:51 PM
Ryan M Ryan M is offline
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Brake cleaner, locktite, wd40, blah blah blah. What do you need that stuff for? Just get out your tools and get to work. With all do respect, you're making this harder than it has to be. This job can't be easier.
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  #35  
Old 03-04-2008, 09:26 PM
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Quote:
Originally Posted by bluebee View Post
.........BTW, I'm a program manager. I analyze and organize projects much more complicated than a brake job for a living. Almost all of them go wrong in some way or another as we're always working things that have never before been done. In the post mortems, we find, in general, the mistakes were simple to predict, if only we knew enough ahead of time what simple things to look for......
My life experience and my current job showed me numerous times that people who are over analyzing, (meaning, people who can not realize when the solution already presented itself.), and continue to analyze beyond that point, will ALWAYS choose the wrong product and/or solution.

I would therefore predict this: 95%, You will choose the wrong rotors and pads.

I would also suspect that most times your project go wrong because simple things were ignored, is because you were over analyzing and therefore missed the obvious.

All in all, although this is getting somewhat boring, it still has some entertaining qualities to watch. Like watching a train wrack about to happen.

No disrespect to you. Just my observations.

mw

P.S. I am wondring about the research paper you might have about prepering a hard boiled egg?

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  #36  
Old 03-04-2008, 10:31 PM
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la528it la528it is offline
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Quote:
Originally Posted by MatWiz View Post
P.S. I am wondring about the research paper you might have about prepering a hard boiled egg?

.
Easy, at x-mas my mom bought me a plastic egg that changed colors from the inside out, replicating how well cooked the eggs are. This thing works like magic: granted you must watch the plastic egg to know when to stop, but this has taken all the guessing out of it. If you want the heat absorption equations, you can call up stephen wolfram, or ask the original thread started


J/K good thread
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  #37  
Old 03-05-2008, 05:20 PM
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Just to explain, I first looked up all that I could find to do an E39 brake job. I was appalled at the lack of a good E39-specific tutorial. Even the better tutorials I found later (with your help) were missing critical steps.

Given that, it's no wonder each mechanic stumbles through the same mistakes over and over again. I'll be no exception. Hopefully the ones who follow us will have progressively fewer mistakes until the job goes off for a total newbie like I am, without a hitch.
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  #38  
Old 03-05-2008, 07:06 PM
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Quote:
Originally Posted by la528it View Post
Easy, at x-mas my mom bought me a plastic egg that changed colors from the inside out, replicating how well cooked the eggs are. This thing works like magic: granted you must watch the plastic egg to know when to stop, but this has taken all the guessing out of it. If you want the heat absorption equations, you can call up stephen wolfram, or ask the original thread started


J/K good thread


With all due respect to your mom's good intentions. But that little plastic egg she gave you is analogous to the fish that you are not suppose to give to a hungry man. You suppose to teach him to fish, so that he could eat for life. Think of all the life lessons you could have learned if you studied the affect the intensity of the heat vs. the width of the pot vs. the ratio of the hight of the water to the volume of the water vs. the number of eggs in the pot. There is also the ratio of the total volume (cubic inches) of all the eggs combined to the cubic inches of the water. How fast the water will boil will affect the comparative hardness of the white part of the egg to its yolk. Do you like it when the middle of the yolk is still a little running? Did you boil the egg too fast? Did you boil the egg too slow? Do the water really need to boil for the perfect hard boiled egg, or maybe a temperature at a controlled point below boiling is better.

As you can see, there are many ways you can fail boiling an egg. We need to research this before we prepare our next egg. Could somebody do this take pictures and post? Maybe if others can please pitch in and contribute to the knowledge so we wont fail with the eggs. Any other pitfalls we miss seeing? The thickness of the shell? How does that affect cracking? Will cracking water down the egg?

This is not simple. I don't think I could enjoy an hard boil egg any more, now that I just thought all that.

mw
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  #39  
Old 03-06-2008, 04:35 PM
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Quote:
Think of all the life lessons you could have learned if you studied the ... hard-boiled egg
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  #40  
Old 03-06-2008, 06:52 PM
oconnmic@hotmai oconnmic@hotmai is offline
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In theory, theory is just like reality. In reality it isn't.

That said, do semi-metallic and ceramic pads wear out rotors faster than organic pads or not?
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  #41  
Old 03-06-2008, 07:30 PM
larobj63 larobj63 is offline
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This is an amzing thread!

Dude, if you placed a value on your time - what's your billable rate in your line - maybe $100.oo /hr? You're in this project like 700 bucks and you haven't even ordered the materials yet!

I'm sorry - I don't mean to be a d*ck. I'm an engineer - but I can't relate man. I work on much more horse and common sence, I guess...
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  #42  
Old 03-06-2008, 09:44 PM
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Quote:
Originally Posted by oconnmic@hotmai View Post
In theory, theory is just like reality. In reality it isn't.

That said, do semi-metallic and ceramic pads wear out rotors faster than organic pads or not?
That depends. Are you asking in theory, or in reality?

mw
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  #43  
Old 03-06-2008, 09:57 PM
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Quote:
do semi-metallic and ceramic pads wear out rotors faster than organic pads or not?
It seems, based solely on my extensive research (which means I could easily be wrong), that semi-metallic friction materials, with their inevitable matrix of heat-conducting, yet sehr abrasive chopped steel fibers and steel wool, are at once noisier, darker dustier, and yes, my dear, they definitely wear out cast iron rotors about 10% faster than ceramic pads (which seem to use copper threads) according to Marc at Zeckhausen Racing in a phone conversation with me earlier this week).

Unfortunately there is no formal government standard for brake friction materials that you can bank on. So, what constitutes a "ceramic" pad, out of the 20-40 components typically used in the mix, is up to the manufacturer's marketing department to decide. So, one guy's ceramic pad might be rougher on your rotors than someone else's semi-metallic brake friction material, merely because they are both the same (or very similar) composition, marketed differently.

Notice these graphs which give the Axxis ULT (i.e., marketed as a ceramic pad) a rotor-life factor of 5 versus the Axxis Deluxe which they give a lower rotor-wear factor of rotor-life 8.
http://www.brakewarehouse.com/axxis3.asp
http://www.brakewarehouse.com/axxis1.asp

Now why they can't make semi-metallic with copper threads is beyond me; we'll leave that for someone else to decipher.

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  #44  
Old 03-07-2008, 09:09 AM
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BTW, I've decided upon Axxis pads but I myself am choosing among them:
Does this seem like a reasonable comparison?

Axxis Deluxe Advanced
Good in every respect (braking, sensations, fade resistance, rotor & pad life, etc.)

Axxis XBG
About the same as the Axxis Deluxe Advanced, 'cept maybe in initial pedal feel.

Axxis ULT
A little noiser & dustier, less rotor and pad life, but slightly better than XBG and Deluxe Advanced in their braking characteristics.

Axxis Extended Duty
Same as XBG but last longer.

Is my quick assessment reasonably accurate? They're all basically the same?
(If so, I'd select by price, in ascending order.)

What do most of you use for Axxis pads on a normally driven bimmer (by normal, I mean normal highway speeds of from 70-85, a bit higher when passing, and stop-n-go driving to take the kids to school, just a couple of panic stops a week, rarely repeatedly, and I never clean my car, having grown up in the east coast where we don't consider our cars an extension of our personality).

Last edited by bluebee; 03-07-2008 at 09:17 AM.
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  #45  
Old 03-07-2008, 09:17 AM
dvsgene dvsgene is offline
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Quote:
Originally Posted by bluebee View Post
Unfortunately there is no formal government standard for brake friction materials that you can bank on. So, what constitutes a "ceramic" pad, out of the 20-40 components typically used in the mix, is up to the manufacturer's marketing department to decide. So, one guy's ceramic pad might be rougher on your rotors than someone else's semi-metallic brake friction material, merely because they are both the same (or very similar) composition, marketed differently.
Yes, unfortunately, comparisons between manufacturers on standards are always hard without an independent testing facility or entity setting the standard.

Just like a Mobil1 5-W30 has a different viscosity vs a Catrol 5W-30 or a treadwear on a Dunlop with a rating of 200 vs a Michelin will be different. As companies achieve these numbers based on their "baseline" which may be different than another companies baseline which falls in line within a range of an industry "baseline" standard.
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  #46  
Old 03-10-2008, 02:07 PM
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I started the rear brakes last night after getting home from vacation

I've been on vacation with the bimmer up in the snow so sorry I haven't posted recently.

May I ask how much does a couple of thousands of inches matter?

The rear rotor thickness limit is 0.720 inches and a measurement in a dozen places shows it is above that by a few thousandths, e.g., it was from about 0.724 to about 0.730 inches.

Since I'm, at best, four thousandths above the limit, does that mean I can "safely" get away with not replacing the rear rotors?

I guess I'm asking, how close is too close to the limit?
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  #47  
Old 03-10-2008, 03:26 PM
dvsgene dvsgene is offline
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I've been on vacation with the bimmer up in the snow so sorry I haven't posted recently.

May I ask how much does a couple of thousands of inches matter?

The rear rotor thickness limit is 0.720 inches and a measurement in a dozen places shows it is above that by a few thousandths, e.g., it was from about 0.724 to about 0.730 inches.

Since I'm, at best, four thousandths above the limit, does that mean I can "safely" get away with not replacing the rear rotors?

I guess I'm asking, how close is too close to the limit?
Donna,

I am not sure how many people on this forum use micrometers to measure runout. Nor do I know of many indys or dealers let alone DIYers whom by nature are trying to save some money would not go out and buy expensive micrometers and digital calipers. Most will take a look at the rotors and if the feel a significant lip on the edge of the rotor (running your fingernail along the edge and getting caught) will replace it or if DIY will usually replace them after going through 2 sets of brake pads(depending on type of pads being used- more abrasive metallics vs less harsh ceramics)

The question really becomes:Will .004 to .010 last before the next brake pad change? If not, you'll find yourself either below recommended limits before the next pad change or replacing the rotors before the new pads you just put are worn out. Thus requiring disassembling the brakes a second time and then replacing the pads again for a third time shortly thereafter. My recommendation would be to just go ahead and replace the rotors since you are putting new pads that are a different composition than the previous set of pads. This is because new rotors and pads will help with bedding in pads. A new surface will bed in easier to bed in than an older rotor with a different pad material embedded in the rotor. And since the measurements indicate differences ranging from .004 to .010 in various parts indicates a bit of uneven wear. To even it back out, turning the rotors with a lathe may be necessary and by turning the rotors you'll wind up removing more material bringing you closer to the 0.72 limit anyway.

To make along story short, I personally don't know how much of a difference .004 to .010 makes or lasts but if I think through the logic in the previous paragraph, I would just replace the rotors. The other piece of information that's missing that I couldn't find was what is the measurement of a brand new rotor. If a brand new is say 0.74, then it's safe to say the current one needs replacing from a measurement standpoint. Hope that logic helps.

Last edited by dvsgene; 03-10-2008 at 03:32 PM.
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  #48  
Old 03-10-2008, 04:51 PM
KeithS KeithS is offline
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Join Date: Dec 2001
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Mein Auto: '11 335d, '00 540iT
Very cool thread, I throw in my 2 cents

I've been messing with BMW brakes for 4 years now on 2 different cars. This is what I have observed.
  • NOTHING will give the initial bite of the dusty OE semi metallics
  • Much of that dust (especially the parts the seem to burn into your wheels) is abraded brake rotor
  • One of the reasons of the high initial bite along with quickly wearing rotors must be the high metallic content. With OE pads & 30K miles and you have a significant lip on the rotor due to the wear
  • I am running Axxis Deluxe on my 3. Noticeably less initial bit, but you get use to it and car stops fine.
  • With the Axxis almost no dust
  • With the Axxis it appears pads will last 1.5x longer than OEM
  • With Axxis at 30K miles there is NO wear on the rotors (no lip at all)
  • Just installed Akebono Euro Ceramics on our 5. Better initial bite than the axxis (but still less than OEM).
  • All I use when installing is disc brake grease on the slide pins, and a very light coating of high temp anti-seize compound on pad backing and ears (where it contacts metal) and have no squealing issues.
Hope this provides some more data for those who like to analyze
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  #49  
Old 03-10-2008, 04:54 PM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,106
Mein Auto: 02 BMW 525i M54 auto 130K
What does the wear limit REALLY tell you?

Quote:
The question really becomes:Will .004 to .010 last before the next brake pad change? If a brand new rotor is, say 0.74, then it's safe to say the current one needs replacing from a measurement standpoint.
That's EXACTLY my question!

Thinking more along these newly logical lines ...

The rear rotors start at ~20mm (0.787 inches) and the wear limit stamped on the rear rotor is 18.4 mm (0.720 inches in the Bentleys).

If the wear limit is 0.720 inches for a rear rotor, I'm assuming that means the wear limit really isn't a wear limit, it's a pad-replacement limit. The true it's-too-thin-now wear limit would be, I'm logically assuming, 0.720 inches minus whatever is normally worn off the rotors during the lifetime of a single set of pads.

Given I have 60K miles, I'm assuming that's two sets of pads in the rear, and given the rotor started off at 0.787 inches and it's now roughly 0.727 inches, that makes it about 0.030 inches per pad set.

That would mean the TRUE wear limit for these rotors is 0.720 minus 0.030 inches, which is 0.690 inches.

Does this make logical sense to you that, in summary, each set of pads eats up about 0.030 inches of rotor, and that you can put pads on the rears at 0.720 inches, so, the true minimum thickness, after those pads are worn, would be 0.690 inches?

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Last edited by bluebee; 03-10-2008 at 05:15 PM.
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  #50  
Old 03-10-2008, 05:04 PM
KeithS KeithS is offline
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Location: Central NJ
 
Join Date: Dec 2001
Posts: 1,617
Mein Auto: '11 335d, '00 540iT
Just found this which may help:

Another reason to replace rotors rather than turn them is that each rotor was a minimum wear limit, and a minimum machining limit. Usually the machining limit is .030" greater than the wear limit, but that is trivial. What is important to me as a mechanic is whether or not I can make a good cut and still have enough material left to be well within the machining limit. If I have any doubt at all, like for example if the front rotors have deep rust, which is common in NE where I live these days, I will state flatly that the rotors should be replaced, period.

So this seems to be saying that as long as you are not past the wear limit at the time of replacement, there is cushion built into the measurement to allow for the wear caused by another set of pads (Disclaimer - I am not a mechanic, do not take my word for it)
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