TheHummel

I'm baffled- I have a 951 with a recently installed re-manufactured power steering rack and pump (installed 3 months ago). Everything worked well until it started to make disturbing grumbling noises when turning right. I assumed this was due to low fluid level as I have read, but the fluid level was fine. I filled it up a tad more anyway but it doesn't seem to have helped. Shortly after I start the car and the PS is gone. I checked everything- fluid, belt, hoses, etc. but everything seems fine. Hoses are new and updated versions. I doubt they have collapsed. I don't remember anything unusual before the noise started and before the PS died. No foam either.

What am I missing?

F18Rep

Any chance it could be the pump? Bruce

TheHummel

Update.

Replaced the pump and the steering has returned, but the grumbling persists just as before. Pump was a casualty of the problem no doubt.... but I have yet to find it. Other than the reservoir to pump line, which areas could cause a problem like this? Its a persistent grumble which seems to arise from turning right, but doesn't always stop when centered or can sometimes simply start and stop when sitting still. It is quite noticeable but only inside the car.

944Ross

The reservoir has an integral filter. If your previous rack/pump were spitting out shavings, it could be plugged. A starved pump will make groaning noise. Only option is to replace the reservoir, filter can't be cleaned.

ehokana

I would second that one. Probably a clogged filter in the reservoir. Pretty easy fix if that's the problem, and it couldn't hurt to replace it anyway

Van

I have some used reservoirs... Came from cars with good power steering! (Manual rack conversions) Let me know if you want one.

TheHummel

Well I got a new reservoir in. The problem persists... although maybe slightly less loud and noticeable? Although that might just be my head playing tricks on me. Now I'm at a loss. What else could it be?

mblaszak

BEFORE you installed the replacement pump and rack, did you flush the system with new fluid (lots of it!). Most do not, they just bolt it all together. ONE spec of contamination jambed in the relief valve of the pump will cause problems. To me it sounds like the pump bypass. When it is making this noise, do you have less steering assist? If you can't tell, then you need a gauge installed in the system to measure system pressure (which is over 1000 PSI BTW).
Just a thought... of course you can have a defective pump again too. Not all parts are created equal. Some rebuilders think spray paint and an o-ring is "rebuilt"

TheHummel

Yes, new fluid all around when I installed the first pump, then again when I installed its replacement. The first pump was a rebuilt unit I got off ebay. It seemed fine, but there is no telling if it was good or not internally. The second one was another rebuilt one from Rock Auto, and seems to have a more professional quality to it. I doubt it is the pump. The problem is exactly the same as before. Steering works fine and feels fine, the noise is the only indication something is wrong while driving.

There is the possibility that the pump failure might have been a red herring. Perhaps the first pump was just bad, and something else in the driver's side suspension is making the noise. I did replace the bushings and got new strut mounts recently. However, I don't think that would explain the noise when the car is not moving but on.

TheHummel

Update

I took apart the old pump. The big thin film gasket was obviously not put in correctly and didn't line up with the pump housing. I think it was a bad rebuild, not a lack of lubrication that caused the failure.

I don't think it is the power steering system making the noise anymore. I think it is something on the firewall vibrating and making a noise inside the cabin. Its really loud and obnoxious still. I got a stethoscope and poked around with it but couldn't find anything.



So, what could be loose, vibrate with a rapid but intermittent frequency, and is along the driver's side portion of the firewall? Brake booster and clutch look fine, checked that...