I bought my 1987 S4 as a non runner but now it is and I find the steering extremely heavy at parking speeds. I have not driven another for comparison but I have some new observations.

1) Just recently we had a cold snap (35F) and when I first started, the steering almost felt reasonable. As soon as the fluid warmed it was back to the usual 2 handed grunt to park it.

2) With the wheels off the ground it is extremely easy to move the wheels from lock to lock with the engine stopped.

3) I have stock wheels and tire sizes.

Could there be an internal leak in the rack which then allows equal pressure to both sides resulting in zero boost?
Did the low temperature tighten up a seal for a few blissful moments?
Can the racks be rebuilt at home? - I already rebuilt the engine and TT myself.
Should I join a Gym?

Any thoughts??

Brian.

 

Is your belt glazed ?

 

Brian............check all the basics, fluid level, is it flowing with engine running, reservoir age, is the rack leaking, belt/pulley condition?

 

did you replace the Hi pressure line from the back of the pump to the rack?? Hi pressure line is the one thats flexible and runs along the top or the shock tower and it has a round piece of rubber on it this is a restriction for the LO speed boost, if you replaced the line then you have less boost at idle.
Anyhow I would suggest that you change the fluid, and see if the old stuff has any silver particles in it.
If it does then the pumps probably going bad..
To change fluid, undo one of the lines to the bottom of the rack and then turn the wheels back and forth with the egine off this will get most of the fluid out.

 

All basics have been checked - new reservoir and low pressure lines, new belt, pump flows fluid (seen while refilling reservoir), no external rack leaks, original HP lines with restrictor still in place.
I am really looking for insight into the operation of the rack itself.

Thanks, Brian

 

what color is the fluid? Can you see any silver in it drip some onto a black piece of cardboard and look at the oil in the sun if you see metallic specs the pumps going bad.
Did you pull the inner rack boots off to see if there are leaks?

 

Did you mix up the lines? Return line is to the rear IIRC.

 

Dave brings up a good point,

 

Fluid is clean. There is no leakage into the rack boots.
I have had no reason to disconnect the pressure lines from the rack but I will check to see if a PO has done something stupid.

Thanks, Brian

 

1.Does the steering wheel hub rub on the pod cover? If the pod is rubbing, loosen the allen bolts and push it forward and retighten.

2. Does your car have an LSD rear end? If so, you might need to change the oil and make sure it has the proper additives.

My guess is #2.

 

Another possibility is that the filter in the reservoir is clogged. I would expect pump cavitation noises(groaning) if that were the case though.

Pressure is controlled by a pressure drop across an orifice acting against a spool valve/spring(f) which opens a bypass passage at the pressure setpoint. If this is gummed up or the pressure relief valve(h) is not sealing then you will not get the normal amount of power assist.

Having said all of that, the car will not steer with one finger at parking speeds like a domestic. It should take a firm grip and a few pounds of force, but should not involve "two-handed grunting".

For safety, come to a complete stop before engaging in "two-handed grunting"

 

SharkSkin, this is good information. I have already replaced the reservoir so that is not an issue.
Looks like the only way to check pump output is with a pressure gauge as shown in the WSM but I am a little reluctant to attempt this knowing the pressures involved. Also, finding adaptors to the banjo fitting may be a trial.
Has anyone done this at home?

 

please take a picture of the connections at the bottom of the rack and post it there should be 4 banjo bolts that hold lines, 2 of the lines run up the side of the inner fender

 

Silly question
Have you driven another 928? They do have heavy steering!

Marton

 

Awesome post Dave!

I too have unusually heavy steering - even after recently replacing my high pressure line, reservoir, reservoir line and cooler line, and flushing the rack a lot.

I've driven a local's identical car to mine (another '89 manual S4) and while his shifter and clutch felt sloppy as hell, his steering was a lot lighter.

I do have some power assist - I've driven mine with the belt removed to get home after I suffered a leaky high pressure line, and it was heavier, but it seems I have reduced pressure.. so rebuilding a spare pump I have handy looks like the next option before I try a rack rebuild (PO replaced my rack 3 years ago).

Hilton.