Power steering pump problems.

[KooK]

Before we really get into it, 1984 633csi, old pump style (prior to april 84). What type of fluid am I supposed to be using here?

I'll just come out and say it, I've replaced the power steering pump twice now, the first time it was ok for a few hundred miles before it started whining again, this second one started to whine right off the bat. I was told to use Merc/Dex as power steering fluid which didn't seem right to me AT ALL, but I went ahead anyway. The return line has a 90 degree fitting in it so it's not being restricted, and at this point, I can't figure out why it would be doing this unless it was the fluid.

[HayekFan]

Longshot, but could you have gotten two bad replacement pumps? I bought a rebuilt one from Autozone for my Toyota and it failed almost immediately. I exchanged it for another and had no problems after that. Course, odds are low that you'd get 2 bad ones.

Dextron is correct.

[KooK]

Given the company that rebuilds these, I guess that is possible. I'm just going to order an OEM BMW pump this time I guess and see how things go.

[sixseries]

yeah its ATF fluid. wierd

[HayekFan]

So the pumps were from an Autozone type place? Could be that the same guy rebuilt them and made the same mistake on both. It would be interesting to take a hidden camera into one of those reman shops. There's no telling how their quality control is, or how well trained their people are.

On the other hand, I've bought lots of Autozone parts and have only had problems on two occasions. That ps pump, and a brake disk whose stud holes didn't line up quite right.

[alpinacsi]

3 things that frequently happen with power steering pump replacement:

1) wrong fluid: you seem to have this sorted out.

2) failure to replace filter. The filter is in the bottom of the fluid reservoir.

3) improper filling of the system. Many people have the tendency to over fill the system. Since the brake and power steering systems work together, you have to go thru a different fill proceedure. You will need to pump the brake pedal with the car off 20 -30 times to release the fluid from the brake accumilator. this will back up into the power steering fluid reservoir and then it should be filled to about 10mm or 3/8" from the top.

[jdkirkk]

3 things that frequently happen with power steering pump replacement:
3) improper filling of the system. Many people have the tendency to over fill the system. Since the brake and power steering systems work together, you have to go thru a different fill proceedure. You will need to pump the brake pedal with the car off 20 -30 times to release the fluid from the brake accumilator. this will back up into the power steering fluid reservoir and then it should be filled to about 10mm or 3/8" from the top.

The '88 635 that I just purchased from an estate was overfilled and now I know the probable reason why. Thanks for the correct technique.
The car had been in the hands of a "foreign car mechanic" which is not the same as a "BMW knowledgeable mechanic." ;-)

[CW6er]

Changing the filter and flushing/filling the system:

http://bigcoupe.com/phpBB2/viewtopic.php?t=2314

Whining or groaning in a power steering pump is quite often caused by cavitation or air getting into the system:

When you put the new pump in did you replace the sealing crush washers on the pump inlet banjo bolt? Is the pump supply hose soaked with fluid? If so, if fluid is getting out, air can get in. If the hose looks ruff, just replace it.

If the pumps have a warranty, just keep going back until you get a good one!

[KooK]

I bought a new filter for it, but it doesn't look right, it just kinda sits in there with huge gaps on the sides, unless it expands when it gets hit with fluid?

[CW6er]

Not quite sure what you mean by "it just kinda sits in there with huge gaps on the sides,"? The filter seats on the bottom of the canister and is capped off by the spring loaded cup (#10) on top. The fluid returns to the bottom of the canister, to the inside of the filter and flows out through the sides of the filter, filling the reservoir and then leaves the reservoir out the side outlet to the pump. The spring loaded cap serves as a pressure relief if the filter gets clogged. My car doesn't have #17 and apparently many don't.

Now, there are two different sizes, did you get the wrong size? Is it too small for the top cap?

http://bmwfans.info/original/images/3739_p.png

http://bmwfans.info/original/images/3763_p.png

[KooK]

*raising eyebrow* I think I'm missing a few things...

[CW6er]

What's missing?

[KooK]

8, 9, 17, 10 are all missing from the first image.

[alpinacsi]

17 was not always used (actually I do not recall ever seeing it) but 8,9 and 10 are definately needed to hold 11 (the filter) in place.

[KooK]

Now you can understand my confusion! :D

[Gehrke69]

I'm just beginning to restore my 84 633csi. I've passed this along to my mechanic. Thanks