DIY: 1998 528i S.A.S Pierburg Air Pump Maintenance and Rebuild Info

DIY: 1998 528i S.A.S Pierburg Air Pump Maintenance and Rebuild Info

* Look up how S.A.S. works, basically at cold start, the S.A.S. Air Valve opens and the Air Pump injects extra air into the exhaust system to reduce polution.

* When Air Valve fails in OPEN position, exhaust flows backward into the Air Pump with water vapor, destroying the Air Pump.
Then no extra air is injected into the exhaust system at cold start, the ECU will register a P0410 OBD-II Code (S.A.S. Fault) because the O2 sensor does not sense a change in readings as programmed.

* Best is to prevent damage to Air Pump: Every 80-100K miles:
- replace the Air Valve as there is not much lifespan remaining.
- replace the vacuum hose, use only thick-walled vacuum hose to prevent hose collapse under vacuum suction.

I also own a 1998 Volvo V70, and the Volvo Air Pump is also made by Pierburg, so the idea is the same. The BMW and Volvo Air Pumps are very similar (almost 95% the same). Actually with this info, you can apply to any European Cars (VW, Audi, MB etc.) with this setup of Pierburg Air Pump.
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DIY Instructions:

1- To replace the Air Valve. This is a 10-min job.
- Air Valve is #14 (It varies from year to year), Gasket is #15. Vacuum Hose (use any thick-walled vacuum hose that matches size)
http://www.realoem.com/bmw/showparts...39&hg=11&fg=45

- New Pierburg Air Valve is $107 at EACTuning:
http://www.eactuning.com/parts/produ...ls/11727540466

- Make sure you don't over-tighten the 10-mm nuts.
Look it up but I think the torque is 10 Nm, basically snug and tug a bit!

*** Now if you read Step #1 above and change the Air Valve and its hose every 80-100K miles, you don't need to read further. Info below is for those who want to tackle the Air Pump should it become defective.




2. To REMOVE Air Pump for rebuild:
- Front Passenger Tire off
- Passenger Front side on Jackstand
- Front Wheel Vinyl Fender off (8-mm screws)
- Using a Long Extension and Ratchet, remove the 3 screws (10-mm) holding the Air Pump BRACKET. Do not touch the 10-mm nuts holding the Air Pump to the BRACKET because you will regret you did that!

- Disconnect Hose Clamps and Electrical Connector and the Air Pump will come out.




3. To REBUILD Air Pump.
Rebuild only if you are short of budget and has the skills/desires to do it. With proper tools, it is easy.
Without proper tools ---> order new Air Pump!
Information is included here for those who have the skills and tools.

- Follow the instructions in the attached pictures:

- This is from my 1998 Volvo V70 but it is the same for BMW E39, use 6 paper clips to wedge the flange and pull it out:




Here is the BMW E39 Air Pump:











Tips/Tricks:
- To drill out the Six (6) rivets holding the Air Pump, use a 5/32" drill bit, the rivets will come out nicely.
- Use liquid paper to mark alignment of Air Pump housing to make re-installation easier (don't you want your life easier?...)
- To re-install, use #8-32, 1.5 inches long nuts and bolts. You need a tocal of Six (6), Hardware store sells this package for $0.99.
- After the nut is tightened (don't over-tighten the nut), I use a pair of vice-grips and crimp the protruding threads on the bolts to prevent the nuts from working loose; kind of locking the nuts in (I did trick on my Volvo one year ago and the nuts hold tight).


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I just spotted Item #11 (Basically the Air Filter for the SAS Air Pump) has never been discussed in this forum. I have never paid attention to this "Piece of Crap" until now. It is in the second picture of my post above (next to the word "Air Flow").

BMW PN 11721744340



I guess it is out-of-sight-out-of-mind kind of thingy.

Very informative, thanks as always cn!

Great write-up. I hate the SAS unit so much... *grumble grumble*

wish i had the rebuild info for when mine went out. but just to let you know i got a replacement air valve at carquest for 80 bucks.

Originally Posted by lild

wish i had the rebuild info for when mine went out. but just to let you know i got a replacement air valve at carquest for 80 bucks.

Don't get mixed up between:

1. Air Valve: which is not rebuildable.

2. Air Pump: rebuildable.

Nice post cn.

Helpful for WHEN mine goes.

I replaced the Air Valve, gasket and vacuum hose as preventative when I got my touring (easy DIY) ... hopefully it'll help the Air Pump last a little longer.

Originally Posted by Jase007

Nice post cn.

Helpful for WHEN mine goes.

I replaced the Air Valve, gasket and vacuum hose as preventative when I got my touring (easy DIY) ... hopefully it'll help the Air Pump last a little longer.

Smart man!

If you replace the Air Valve religiously every 80-90K or so, the Air Pump lasts virtually forever b/c the Air pump runs only 1-2 minutes and only during COLD start.

It is exhaust gas (when the Air Valve fails) that kills the Air Pump so by preventing exhaust gas from coming into the Air Pump, you significantly extend its lifespan.
Plus when the Air Pump goes bad, you have to replace the Air Valve anyway, costing way more.

Originally Posted by cn90

Don't get mixed up between:

1. Air Valve: which is not rebuildable.

2. Air Pump: rebuildable.

don't worry i'm not, belive me, this could of save me 200 bucks.

Originally Posted by cn90

Smart man!

If you replace the Air Valve religiously every 80-90K or so, the Air Pump lasts virtually forever b/c the Air pump runs only 1-2 minutes and only during COLD start.

It is exhaust gas (when the Air Valve fails) that kills the Air Pump so by preventing exhaust gas from coming into the Air Pump, you significantly extend its lifespan.
Plus when the Air Pump goes bad, you have to replace the Air Valve anyway, costing way more.

Which Real OEM page has the air pump/valve etc? I can't find it. I'm assuming it is also installed on a 03 525. Just adding to my list of diy's. Thanks.

Originally Posted by dcotti

Which Real OEM page has the air pump/valve etc? I can't find it. I'm assuming it is also installed on a 03 525. Just adding to my list of diy's. Thanks.

Search realoem.com under "Engine Vacuum" section.

Is the secondary air pump really a necessity?
I have rough idle at start-up...
I am attributing it to my 2nd bad CCV and the secondary air pump...

Thoughts?

Thanks!
Jason

doubt it's that. i have the same thing, rough idle on cold start too.

No joke! I'm working on using a vacuum cleaner motor to replace the whole unit. Will let you guys know how it goes!

Isnt there a power chip or something that just totally eliminates the SAS from the on board diagnostics? I will defenetly go that route when/if mine fails.

Someone asks me about the special puller to remove the Impeller.

Without the special puller, you can still pull the Impeller using this home-made method:

1. Using a Vice-grip and appropriate nut, bite both the collar and the nut so they become one unit.

2. Then use appropriate bolt to remove the collar.

Basically this is a "home-made" puller!

Update:

For those of you who want to rebuild the Air Pump's electric motor, use bearing with this size 6 mm x 19 mm x 6 mm (ID x OD x thickness). It is commonly used for roller blade, believe it or not.

Choices are:
- SKF 626 ($8 + shipping on ebay)
- Timken 36pp ($12 on line)
- No name 626RS. Go to ebay and enter: "626RS" or "6 x 19 x 6 bearing" ($7 incl. shipping on ebay)

HTH

I take it that you were able to separate the impeller using your special technique w/ the vise grip ? IF so, where did you find the appropriate size nut to work with the visegrip? I had no luck separating the impeller. The Vise grip trick requires too precise of a nut to be able to clamp the two parts with even force. I even welded the nut to the visegrip,
but when I went to crank down on the bolt to separate the impeller, the vise grip slipped out of the head of the impeller, and that left me with a set of visegrips I could no longer open out again.

Unless I come up with another idea,
this is one part that I'm not going to DIY.

DHoang,
I guess you can bring it to a machine shop, they should be able to remove the impeller for you.

I wrote this DIY for those who want to rebuild the Air Pump using new bearing. The reason for the above DIY is that this electrical motor for the Air Pump is very very and very difficult to find.

UPDATE:

- I opened the Pierburg Air Pump and did an autopsy on it:
The Electrical Motor is Johnson HC971(2)LG-101.

I contacted Johnson Motor and they only sell this motor to Pierburg and not to the public:
http://www.johnsonelectric.com/media...&IdProduct=604



Spec for Johnson HC971(2)LG-101 is:

Size: Diameter 52 mm x Length 85 mm: shaft Ø 6.005 mm

-----------------No load---------Stall-----------Max efficiency----------Max power

Speed (rpm)..........6400..................-.....................5600......................... 3200

Current (A).............1.20...............53.65.......... ......8.02...........................27.43

Torque (mNm)..........-................915.92...............119.07....... ..................457.96

Efficiency (%)............-...................-......................66.67....................... ....-

Power (W).................-...................-..................... 69.50........................153.63

----------------
After a lot of internet search I found a motor that hobby-lobby people use Graupner 900 BB motor to power their toy air plane that has virtually identical spec as Johnson Motor.

So we need someone to try this "guinea pig" for the rest of us.

The good news is that: in contrast to Johnson electrical motor (which is made in China for Pierburg!), the Graupner 900 BB motor ($59) is made in Germany:

http://www.hobby-lobby.com/speed_900..._2581_prd1.htm


Specification for Graupner 900 BB motor

Nominal voltage 12 V (this is the same as Pierburg Air Pump)
Operating voltage range 6 ... 40 V
No-load rpm 6500 min–1 (this is the same as Pierburg Air Pump)
No-load current drain 1,1 A

Current drain at max. efficiency 8 A

Current drain when stalled 54 A (this is the same as Pierburg Air Pump)

Max. efficiency without gearbox 71 %
Length of case, excl. shaft 85 mm (this is the same as Pierburg Air Pump)
Diameter 51,5 mm (this is the same as Pierburg Air Pump)
Free shaft length 15 mm (this is the same as Pierburg Air Pump)
Shaft diameter 6 mm (this is the same as Pierburg Air Pump)
Weight 645 g

For those of you who want to see the anatomy of a typical Pierburg Air Pump, here it is. I just took the picture today. You can see that the motor shaft is 6-mm and is press-fit into the impeller. So with some WD-40 the day before, vice-grip on the stub of impeller and a 5-mm drift, you can tap the motor out:

Pulled my air pump out today to clean it out in my 99 528i. Didn't even bother pressing the impeller away from the motor, perhaps later. The motor runs, and even ran a couple days ago on startup (though most of the time it did not run before this cleanout). Sounds like a jet engine, so I'm pretty sure the bearings are failing. My 97 comes on and is nowhere NEAR that loud.

I also pulled the EGR valve out and wiped it down, shot it out with throttle body cleaner etc. Curiousity got the best of me and I blew into both ends. While it was still warm, I could manage to force a little air through both openings. When it was cold, it was not allowing ANY air to get through.

After cleaning and reassembling the pump, including cleaning the foam filter (need a new one, or some foam material to make my own), I reinstalled it, put the EGR back on, replaced the vacuum tube to the EGR (it was rotted and had a hole in it), even wrapped a thick layer of electrical tape on the tube from the pump to the EGR (had a small crack, I will be replacing it shortly), started it up, listened to the pump whine, but the CEL light did not go off.

I went to Autozone to have the CEL reset, but they were already closed.

Is the EGR supposed to be closed when cold? If so, how is the pump supposed to be blowing air through it? Is it spring loaded?

ETA: Whose stupid idea was it to put that pump together with rivets?

Originally Posted by cn90

DIY: 1998 528i S.A.S Pierburg Air Pump Maintenance and Rebuild Info

S.A.S.

*******>********>

Noun

1.

SAS - Special Air Service - a specialist regiment of the British army that is trained in commando techniques of warfare and used in clandestine operations (especially against terrorist groups)

Small Astronomy Satellite, a series of NASA satellites

Secure Attention Sequence or secure attention key, a method to invoke a computer operating system's attention, usually signaling it to show the log on screen

A self-anchored suspension bridge is a suspension bridge in which the main cables attach to the ends of the road, rather than to the ground via large anchorages. The design is well-suited for construction atop elevated piers, or in areas of unstable soils where anchorages would be difficult to construct.

School of Arts and Sciences

Sex And Suspense

Sealed Authentication System

Seven Abominable Sins

Satellite Audio Service

Seismic Acoustic Sensor

Solid Axle Swap

Steering Angle Sensor (it must be this one!)

Yes? No?

Originally Posted by MatWiz

S.A.S.

It's amazing how you were thinking EXACTLY what I was thinking. Lately, I've been the unofficial maintainer of the E39 glossary located here; and while it explains hundreds of abbreviations, SAS isn't one of them.

I'm assuming it's Secondary Air System but nowhere in this thread does it say what it is.

Lemme google to see if I can find what SAS means in the real world...