Niels Jørgensen

Not that the two are related, but since last weekends track event, the power steering has been noisy, esp. when cold. Fluid is at the low end (touches bottom of dipstick) so I'll top it up today, but I also noticed a thin layer of brownish foam in the resevoir - is it time to flush and refill, and if so, what's the procedure?

Second problem (which might be nothing more than a flaky gauge) is my oil-pressure. When I start the engine it jumps to 5 bar, and never drops below that. In fact, it slowly creeps up to what would have been ~6 bar. There's no noticable difference in the cars performance or sound and oil level is at max (and have been so for several months).

Anyone experienced anything like this?

Nicole

Both sound familiar. When the power steering fluid gets low, it makes this humming sound - especially when cold. I think that might be air bubbles? Anyway, the scary question is where did the fluid go? Did it leak into the rubber boots on the rack, or did it leak at one of the hoses?

When my oil pressure sensor was going bad, it started jumping around erratically. The guys who frist replaced it, tightened it at its housing, rather than the nut - and soon after that it started leaking... In your case, there could also be a faulty contact.

Hope you figure it out quickly and painlessly...

Niels Jørgensen

Thx. Nicole, I've had a power steering leak before and you're right, it's the same sound. If I have a leak, it's very small as the fluid level seems to have stabilized. I was really wondering if hard use at the track could somehow cause fluid to evaporate or otherwise "go bad"?

The oil-pressure thing is odd as it happend yesterday, and rather suddenly, but without any other noticable effect. I'm guessing either sender or gauge have freaked out.

Garth S

Noise and foam are often signs of cavitation in the pump: the first and easiest cure is as you suspect - a correct level of fresh Dexron III. If that does not cure it, there may be damage to the impeller.
There are likely better methods to replace the fluid (see Nichols Tips, etc.), but I disconnect the return hose to the resevoir and feed it into a container ( sone tape and plastic tubing help). Drain the resevoir via the pump supply line and reconnect - or siphon or Mityvac the resevoir dry. Then, preferably with a helper to start the car and rotate the steering wheel - begin adding fresh fluid until you are satisfied with the flush. Top up & hopefully, the problem dissapears.

Niels Jørgensen

Thx Garth, I'll give it a shot later today.

Glenn Evans

Check for leaks, especially check the condition of your power steering hoses. high pressure leaks from these have caused fires and trashed 928s in the past.

With the engine running at idle speed, check that the power steering fluid is level with the mark inside the reservoir.

Top up with Automatic Transmission Fluid if necessary. (Check your owner's manual or seek advice on the type; my 80's says use only Dexron D.)

Park the front wheels on a patch of grass you aren't fond of.

Turn the steering wheelback and forth quickly from lock to lock. This will bleed air from the power steering cylinders.

This miracle cure is brought to you from the Chilton's manual. (Dunno if it's in the 928 workshop manual; I've never looked.)