Catfood

So my 88 S4 has been having some quirks with the power steering.

When I am in parking lots and maneuvering in tight situations sometimes the steering wheel will meet resistance and the wheel will not turn any tighter.

Your first thought may be that the wheel is at its fullest turning angle, but I have checked it and this is not the case.

Any ideas why the wheel will sometimes not turn all the way? Sometimes when this happens I can hear the PS pump whine a bit as I try to push the wheel past the resistance. Could it be a check valve or something?

TIA

Catfood

blown 87

Belt slipping at the pump?

awdmoke

My water pump is leaking, causing the power steering belt to slip & the same symptoms you have.

blown 87

That would be a major leak to get on the belt.

Speedtoys

But...he has a hydraulic whine against the resistance, not a belt squeal.

??

Speedtoys

That's not a leak, that's a tributary.

blown 87

You can have, and often do have slippage of a power steering belt with out whine or squeal, mine will do exactly that with a loose belt.

GlenL

Give a look at the steering linkage.

smiffypr

When you turn the steering wheel, the shaft into the steering rack turns, but the rack pinion resists. This generates movement within the valve assembly, directing the pressurised fluid to move the rack.
This differential movement within the valve assembly relies on a bearing, I think its a needle roller.
Water can get into this bearing down the steering shaft and cause rust in this bearing. Once the bearing movement becomes lumpy, the power assistance can come and go depending on whether this bearing is free or jammed.
This could be your problem.
You can try putting some penetrating oil on the steering shaft immediately above where it enters the rack so that it runs down into this bearing and see if it resolves the problem, or just pull it apart and see if that is the problem.

jon928se

First suspect has to be the PS pump belt. Even without contamination the belt can slip without noise. I had exactly the symptoms you describe following a rack reseal and all new hoses job.

I initially put this down to air in the fluid which does seem to take a while to finally disappear following a fill from empty scenario. Eventually I discovered that the mechanic I used couldn't be trusted to tighten the mounting bolts on the PS pump cassette properly allowing it to come loose and de-tension the belt. He was suitably chastised beaten about the ears and sent home without pay. I was quite happy that my rack rebuild wasn't at fault even though my ears hurt and I felt poorer.

Mike Frye

GlenL

Nor mine or my lawyer, carpenter, plumber...

But they work cheap.