[thaistatos]

Hi,

anybody ever replaced the bearings and or sealings inside in an original ZF power steering pump?
Is it possible or are there parts you cannot buy like special sleeve bearings or sealings?
Does the wheel has to be removed to replace the inner parts?

 

[EdT]

I once replaced the shaft seal on an NG900 pump. It was not challenge-free.

If there's an internal issue with your pump, I think the most effective solution is to install a used one from a parts car. These pumps seem to rarely go bad unless they have been abused.

 

[thaistatos]

I already have an replacement pump from Mapco which seems to start making noise or simply is louder than other original pumps.
The idea was to get a used one and replace the bearing and sealings to have a rebuild pump which hopefully makes no trouble.
I agree that normally these pumps do not make that much problem, but I do not know why it was replaced by the former owner of the car. Just guessing that there might have been a leakage, he forgot to refill and destroyed the original pump. Or workshop simply replaced it without any need or mismatching diagnosis.

Saab luckily provides the exploded view of the pump although they do not offer any spare parts, not even the wheel. There are even the special tools and instructions mentioned to remove and fit the wheel which is required to exchange the ball bearing.

https://saabwisonline.com/images/9600/img-e6/e644s002.jpg

From that picture the bearing should be a ball bearing at the front and most probably a needle roller bearing in the back.
shaft seal at front, O ring at back and maybe some other sealings inside??

 

[EdT]

I had to pull the pulley to change the shaft seal on my pump. I borrowed a pulley puller from a car store (they lend them out in North America). It wasn't quite suitable but I made it work.

A search for "overhaul zf power steering pump" gives a lot of information. Hopefully useful information.

My opinion remains that overhauling your own PS pump is something that you would do because you wanted to try it out. Maybe it is easy and straightforward, as long as there are no major parts that are damaged/worn. But I still think that I would find a good used pump, install it, and drive.

 

[fastcorner]

Pulled the power steering pump out and the high pressure line that screws into the pump has a damaged o-ring. I did not find the replacement part on SAAB web sites. Its a green o-ring and nothing special about it. Went to local parts store and got an assortment of metric o-rings. It is a good match with a 7 mm metric aftermarket o-ring. The aftermarket is a bit fatter than the original. I could take a picture to show the differences. Do you you see an issue of matching o-rings like that or do I need a SAAB OE o-ring?

 

[thaistatos]

Steering Hydraulics (9-5 Parts > Front Wheel Suspension > Hydraulic Pump & Hoses > Steering Hydraulics)

Steering Hydraulics (9-5 Parts > Front Wheel Suspension > Hydraulic Pump & Hoses > Steering Hydraulics)

www.esaabparts.com

#2
As long as it fits, seals and has no problems with temperature and fluid it should be ok.

 

[bob3000]

Its a green o-ring and nothing special about it.

The only thing "special" about the green o-ring is it is viton and made for high temperature and high pressure applications, you should replace it with a viton o-ring.
.

 

[fastcorner]

Good info. I asked the parts guy at the Advanced AutoParts store if the color on the o-rings has any significance. He said NO. That shows how knowledgeable they are.
The Autocraft o-ring pack will not work for this application. There is no reference to high temperature.
Harbor Freight carries a Viton O-ring kit. Does it need to be Metric?

Viton O-Ring Kit, 180 Pc.

Amazing deals on this 180 Piece Viton O-Ring Assortment at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

 

[fastcorner]

Went to HF and I saw three different colors for automotive applications: Black, Brown and Green. The VITON is brown in color. The old o-ring is green. A quick google search indicates that VITOn is the one for widest temperature range. Look attached picture. The one to the right ( VITON Brown 7.65x 1.78) ) is the one closest to the original, left side of the picture, Green Color. Any opinions before installation?

 

[thaistatos]

give it a try. the ring will be deformed anyway, my one looks like triangle in cross section.
As long as it does not spill oil you should be fine, try to move steering wheel left to right in idle and standstill vehicle to check for leakage after installation.

 

[fastcorner]

Its a good description of the old o-ring. Its Green Color with a layer of Brown. My old ring o-ring is similarly deformed.I thought of reusing it but I assume its best to replace it. See attached picture (sorry for dirty keyboard) .Do you know the torque settings for the PS line that connects to the Pump?

 

[thaistatos]

25 lbf ft or 30 Nm.
you can check all specs also in saab wis online

 

[fastcorner]

Thaistatos,
I wrestled with the PS pump for a couple hours until i figured out the tricks to do it. My advice to others is to get the Bosch OEM instead of the less expensive ProParts pump. I ended up using a slightly smaller oring for a better fit. The PS line that goes into the PS pump has 8 or 9 threads. Only about 6 of them get screwed into the pump. Tried to wrench it but did not want to force it.
If I need to redo the work, I will return the ProParts pump and order the OEM.
The most important step during installation is to insert the small bolt into the pump, insert the PS bracket in it and then take your time to insert the PS line as carefully as possible without forcing it.
Thanks for the torque settings. Saved me time.

 

[thaistatos]

I ended up using a slightly smaller oring for a better fit.

even smaller than the 7.65x 1.78?
Do have the exact size available?

 

[fastcorner]

The 7.65 was a bit loose and fell out . I ended up using next size down 6.07x1.78. It works better.
Put everything back together and there are no leaks so far.