BimmerFest BMW Forum banner
1 - 20 of 48 Posts

· Registered
Joined
·
15,776 Posts
Discussion Starter · #1 · (Edited)
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.
---------
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.do?model=DD53&mospid=47585&btnr=11_1539&hg=11&fg=45

- New Pierburg Air Valve is $107 at EACTuning:
http://www.eactuning.com/parts/product_details/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).

---
 

Attachments

· Registered
Joined
·
15,776 Posts
Discussion Starter · #2 ·
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.
 

Attachments

· Sandlapper Chapter
Joined
·
3,634 Posts
Very informative, thanks as always cn!
 

· Technical Graphite > ALL
Joined
·
454 Posts
Great write-up. I hate the SAS unit so much... *grumble grumble*
 

· livin the 'Fest
Joined
·
4,377 Posts
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.
 

· Wrenchin' fool ...
Joined
·
784 Posts
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. :)
 

· Registered
Joined
·
15,776 Posts
Discussion Starter · #8 ·
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.
 

· Registered
Joined
·
105 Posts
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.
 

· Registered
Joined
·
15,776 Posts
Discussion Starter · #16 ·
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!

 

Attachments

· Registered
Joined
·
15,776 Posts
Discussion Starter · #17 ·
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
 

· Gearhead
Joined
·
1,154 Posts
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. :mad:

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

· Registered
Joined
·
15,776 Posts
Discussion Starter · #20 · (Edited)
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/mediando/index.php?IdTreeGroup=179&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_bb_torque_12v_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***8211;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
 
1 - 20 of 48 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top