power steering

[mrbranscum]

I think I have a problem with my power steering. My 86 944 had some problems turning in the cold this winter. I'm thinking my pump is weak, but don't know enough about it to make an educated guess. Can someone help me figure out the route the power steering fluid makes, how it is heated? Some mornings, turning the wheel would give me this awflu noise, like the sound a car makes when power steering fluid is low. My mechanic recently replaced my rack and pinnion steering, if that helps. Does anyone think that the pump is weak, since the car is 20 years old? HELP!

[Eldorado]

mine started doing this when i took it in to get an oil change, and the guys in the garage put in generic 'power steering fluid' instead of the required fluid (ATF i believe)..

[kuehl]

Originally posted by mrbranscum

Can someone help me figure out the route the power steering fluid makes, how it is heated?
The fluid leaves the PS Tank (gravity) and enters the suction side of the pump. The fluid then travels to the steering rack.
Out the rack. Through a cooling loop and back into the PS Tank. Friction & Pressure heat up the fluid.

Some mornings, turning the wheel would give me this awflu noise, like the sound a car makes when power steering fluid is low.
Sounds like atypical "early morning sickness" or "growling" as we call it in PS industry. This could be either (a) problem with the rack's spool valve. As things warm up and expand the problem will go away, however when its cold again you notice it. Or (b) air getting into the system. You would note this by running the system for a short while with the noise. Turning off the engine and looking at the fluid in the PS tank. If you see small bubbles mixed in the fluid then you have air getting into the system. This can come from a handful of suspect areas.


My mechanic recently replaced my rack and pinnion steering, if that helps.
Bring the car back to your mechanic.


By the way, your fluid should be "red" Dexron ATF (automatic power steering fluid, type dexron), any brand will do, you don't need synthetic.

[mrbranscum]

Thanks for the info. In fact, I have seen bubbles in the PS tank upon starting and stopping. Can you help me figure out where the air is coming from? If the ps system is truly hydraulic, then air would be detrimental to the system.
Any advice?

[kuehl]

Originally posted by mrbranscum
Thanks for the info. In fact, I have seen bubbles in the PS tank upon starting and stopping. Can you help me figure out where the air is coming from?
Any advice?

With PS pumps we think of the phrase inertial "cavitation"; when the air bubble in the PS fluid quickly collapses, producing a shock wave, which damages the pump.

There are the usual suspects, however its best to logically follow the flow:

Inspect:
1) hose and clamps between PS Tank and pump.
2) pump's case half's or halves have you.
3) return line starting at the rack, this line will have a rubber section adjacent to the banjo fitting at the rack, and then follow the line across the cross member and then through the cooling coil and back to the PS Tank.

[mrbranscum]

Thanks again. The larger of the two hoses coming from the PS tank was damaged back in the fall. Apparently, the hose was too close to the fan, and the outer wall of the hose was shredded. When I inspected it, the inner hose was still intact. I simply put some duct tape over the area (really well) and moved the hose out of the way. Is it possible that the air in the line is seeping in through that weak spot? I think that maybe I should replace the line jsut to be safe. What do you think?

Maurice

[kuehl]

Originally posted by mrbranscum
Thanks again. The larger of the two hoses coming from the PS tank was damaged back in the fall. Apparently, the hose was too close to the fan, and the outer wall of the hose was shredded. When I inspected it, the inner hose was still intact. I simply put some duct tape over the area (really well) and moved the hose out of the way. Is it possible that the air in the line is seeping in through that weak spot? I think that maybe I should replace the line jsut to be safe. What do you think?

Maurice

Replace the hose, check the hose clamp.
FINISH inspecting the rest of the system.
AFTER you are done with the fixes if any,
Run the system and check for bubbles again, as well as the initial problem you noted.