DIY: 1998 V70 S.A.S Pierburg Air Pump Rebuild (for $20)

[cn90]

DIY: 1998 V70 S.A.S Pierburg Air Pump Rebuild (for $20)

This issue of bad Air Pump has been discussed hundreds of times here. Usually the Air Valve fails, allowing exhaust gas to enter the Air Pump causing damage to it. In the early phase of failing Air Valve, water from exhaust damages the bearings, so change the bearings (x2) ASAP.

Let's assume you already replaced the Air Valve and you need to fix the Air Pump. Some people here drill a hole in the Air Pump to drain water out, bad advice! If you ever drill a hole, drill very small hole, maybe 1/8-inch or so, but no more than that.

Some people here use an old VW Air PUMP, OK, but why use old stuff when you can build the Air Pump back to band new for $20???

PARTS LIST:
- SKF BEARING 626-2RSJEM (double-sealed): $10/each on ebay.
- Nuts and bolts to replace the rivets that you drill out: #8-32 x 1.5 inches long nuts and bolts. You need a total of Six (6); hardware store sells this package for $0.99.

SKF626bearing.jpg (55.98 KiB) Viewed 10307 times

The trickiest part is to get the Impeller out, read on.

PROCEDURE:
1. Search the forum for removal procedure: basically battery out, battery tray out.
There are a total of 4 of bolts: 2 short and 2 long so make a note which one goes where.

2. Once you have the Air Pump out, Take your time to go through all the steps in the pictures below.

Tips/Tricks:
- Use white out paint to mark alignment of Air Pump housing to make re-installation easier (don't you want your life easier?...)
- To drill out the Six (6) rivets holding the Air Pump, use a 5/32" drill bit, the rivets will come out nicely.
(The pics show drilling comes from my 1998 BMW 528i, which also uses a similar Pierburg Air Pump. Shown here for illustrative purposes).
- To re-install, use #8-32 x 1.5 inches long nuts and bolts as mentioned above.
- Use Loctite. 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).
- If you don't have a puller to pull the Impeller, take it to a machine shop and someone will pull it for you.
Otherwise, use a vice-grip and the appropriate-size nut to grab both the nut and impeller's round collar at the same time. Then use a bolt (the bolt is the same type as the nut) to pull the Impeller.

---> Good Luck and Have Fun!

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[cn90]

Edit: you only need one (1) SKF 626 bearing, not two (2) bearings.

[mvferh]

Thank's for the information. It is now on the to do list.

[cn90]

Just pay attention to the DIY, you will be fine.

The tricky part is to pull the impeller off. If you have a smaller puller, you will be fine.

[Matty Moo]

Nice writeup. I remember how frustrating it was to drive around with a CEL from that air pump.

[cn90]

The following observation is from my 1998 BMW 528i: Same S.A.S. system like my 1998 Volvo V70.

You guys will be pleasantly surprised!!!

My 1998 BMW 528i had the usual codes for Air Pump. So I ordered a brand new pump which will not arrive until next week. In the mean time, I reset the CEL light, removed the Air Pump from the car and guess what, for the last few days....no codes at all!
This is because when the Air Valve (which sits on top of the exhaust manifold) is activated during cold start, it acts like a vacuum valve sucking in air. The Air Pump helps push more air in.

When an Air Pump fails, it acts like a road block to air flow because it stops running.

However, removing the Air Pump allows the Air Valve to suck in air as it wishes, which accomplishes the same job of reducing pollutants. It will be a bit noisy during the cold start, then it will quiet down.

So, if you are so tight with budget for a new Air Pump:

1. Remove the Air Pump

2. Reset the OBD-II Check Engine Light.

3. Cap the open end of the hose with home window screen (the same stuff sold at hardware store to repair broken home window screen, which is the screen to keep bugs from getting inside the house). It is a few dollars at hardware store. Then duct tape and gently zip tie it. This is to prevent leaves/debris from getting into the hose.

Try this and report back.

I was pleasantly surprised when I discovered this "Eureka" while waiting for the new Air Pump to arrive. "Look Ma, no code"....
Anyway I already ordered a new Air Pump, so the Air Pump will go in.

The SAS system sounds great in theory but what a piece of junk (to make tree hugger happy for 1 minute!).

[BEJinFbk]

Top Notch Writeup, Sir.
I almost look forward to that pump going out!
Well...Almost.

Great explanations and Excellent Pics.

Thank You!

[cn90]

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 ... roduct=604

Spec for Johnson HC971(2)LG-101 is:
Size: Diameter 52 mm x Length 85 mm: shaft Ø 6.005 mm[/b]

Code: Select all

-------------------------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 ... 1_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

[cn90]

For those of you who want to see the anatomy of a typical Pierburg Air Pump, here it is from my 1998 BMW 528i, other European cars similar. 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:

1998-528i-AirPump-05.jpg (122.11 KiB) Viewed 10036 times

[researchracing]

What a nice write up. My sister in law just bought an older Volvo 850, great shape but the light just kicked on with P0410 code Sec Air Inject System Malfuction. After reading this post which came up first in my Google search I have no concerns about tackling this one if need be. Thanks for taking the time.