anyone replace a power steering pump?
 

I replaced the power steering pump to my '90 944. I have no power steering at all now. Haynes says to bleed the lines by turning the steering wheel lock-to-lock several times while the motor is running. tried it, that wasn't it. Anyone have any suggestions? (I've triple checked my reassembly, seems to be as it should be) Also, why is it the fluid needs to 100% contaminant free? Should all fluids be under the same scrutiny?

What symptoms did you have that casued you to replace the pump?

I had a low, hydraulic sounding hum that would appear after the engine warmed up. The sound was inconsistent, sometimes louder, sometimes under load like in gear, sometimes when idling. Of course, it was classic...you could never catch it when looking under the hood. Mostly, I noticed it when in low gears (probably because the speed drowned out the noise otherwise). Also, the hum did not vary with revs - it was there or it's not but just steady. I suspected the trans for a while but have been able to at least narrow it down to coming from the front right...close to where the power steering pump is. Of course, the hydraulic sound very much sounds like a power steering under duress. Note, AFTER I switched out the pump, unfortunately it was still there, just not as audible. I suspect there is air in the lines and the problem may not be the pump itself but can be solved through the pump and proper procedures. Thanks for asking Scott, hopefully this will help anyone that has a similar situation. I have an S2 cab with 97K miles.

There are 2 diffrent pumps. One is like a 70 bar and the other 105. You need to be sure you replaced it with the same. I have the 105 bar pump, and was shipped the 70 bar.