Garth S

Started up an '89 the other day, and the PS pump was making enough noise to wake the dead. The harsh mechanical clatter and whine had the sound of pump cavitation, as in a dry pump; however, the ATF level was correct. Within seconds, the fluid grew a huge head of froth, nearly overflowing the reservoir. The whine increases as steering input was applied. This looks a lot like an internal bypass problem in the pump - but I'm not sure.
This all occurred at -15C, and largely decreased as the pump warmed up. Steering effort was still normal - and not a drop of ATF leaked from the system. The rack appears and performs fine.
So - is this an internal pump leak? - one that can be addressed with a standard gasket rebuild kit? Or is this just a dead check valve - or dead pump.
Before I plan to bring Jeffs car back to address this new issue, I'd appreciate any input that will help decide the better action course: rebuilt pump ($$$), gasket kit to R&R the pump ($) , or something else. TIA

SharkSkin

Maybe there is some sludge in/near the filter that didn't like the cold. When was the last time you changed the filter/reservoir?

pman928

what is the best way to remove the ps pump? Do you need to disconnect the alternator bracket to get the pump in and out for service?

jpitman2

Just disconnecting the pressure outlet at the rear can be a PITA, if my experience is anything to go by. Needs to be done from underneath. Maybe the oil was near frozen, and wouldnt feed properly?
jp 83 Euro S AT 50k

the flyin' scotsman

Garth............sounds as if the pump was indeed sucking air causing the ATF to froth. Is it possible there was any water in the fluid that would have been frozen preventing the ATF getting to the pump inlet? Jeff didn't put owr steering fluid in the pump did he?

Perhaps wait til it warms up and try it again............if the problem is lessend then perform a fluid change and go from there. If indeed its the pump all you have consummed is some fluid and time; judging by the weather storm in your 'hood you'll have time to come as shall we soon.

Gretch

I agree with the ice in the pump idea.......sounds like a winning diagnosis to me......

Garth S

Jeff had commented that the pump had been 'whining' for some time, although only when a steering input was made. I first fired the car up when on jack stands ( before & after the H20 pump deal), and the pump was quiet ..at -5C: at -15C it was a screamer.
Once fully warmed up, the pump was again quiet - until the wheel was turned. The metallic whining was immediate, as was the frothing in the reservoir. I too thought 'ice', but on a hot engine, that should not be an issue ( after 20 min of running). Jeff drove 100Km home, and the pump still protests with steering input.
I'm still thinking that internal leakage is an issue due to the frothing .... but certainly not confident. Similarly, I'd like to get by with a simple pump rebuild by installation of a kit if that would cure the symptoms. The logistics of getting his car back and apart suggest having a good pump on hand to patch in if a kit will not cure the old one .... I guess ... still

the flyin' scotsman

...........and the potential of power steering fluid?

Sounds as if the 'ice' theory is dismissed so that leaves the fluid, rebuild the pump or replace. IMHO I'd go for the 'new or rebuilt' pump with a guarantee..............that way she's good to go as soon as the big melt happens.........no offence to mechanical abilities.

the flyin' scotsman

I just checked the 928 Int site............yikes; new or used pricey. Didn't see a pump rebuild kit.

the flyin' scotsman

Carl @ 928 Motorsport has a rebuild kit for $28 + logistics but it looks like its only gaskets. Perhaps he can get you bearings also if required.

http://www.928motorsports.com/parts/...rebuildkit.php

RDS928S

First thing in the morning after sitting all night my PS pump makes a "howling/ whine" only during steering input when the car is cold. Say anything below 35 degrees. Once the engine is at operating temp the noise disapears.
Funny though.The car sits outside at work all day in freezing temps. When I leave work the pump does not make noise. Only in the morning?

Dave A.
how do you change the filter or clean the sludge out in the PS pump?

Rich

SharkSkin

I read it on one of the threads hereabouts. I have a different setup, actually. I think it was Dr Bob who pointed out that the later plastic reservoirs have an integral filter, and are meant to be changed periodically. Come to think of it, a clogged filter could have caused ongoing cavitation(Jeff's "whining for some time" symptom) that led to a mechanical failure.

Garth S

Malcolm, Gretch - Sorry, didn't mean to dismiss ice as a factor. That was my first thought too at -15C. It was the continued 'whining' after warm up and a prolongued drive ( 100Km), plus Jeffs later comment that this had been going on for some time - so I concluded that something else was amiss .. too : we've had a really mild winter with lots of above zero, +10C days, and this is a winter driven car.
However, if there is water in the system, it would seek the lowest point - namely, the rack. So ....
Jeff - get your ears on! We are about to start by flushing the PS system. Grab a couple of liters of ATF (Dexron III) and siphon & refill the reservoir daily for a week or so .....take two asprin and call me in a week ....

the flyin' scotsman

No worries Garth; the potential 'ice' issue may have been the simplist of issue.

I sure you know that the 'filter' is an integral component of the reservoir and as such should be replaced.............its cheap compared to the pump! New fluid with a new 'filter' may give the system future longevity...........if not then we'll all have learned.

Jeff928S4

A bit of an update......

The "moaning" is still temperature related. First thing in the morning, it is loud, but only when turning the wheel. Was out driving last night and checked the reservoir - still foamy and it is seeping out from under the cap. After driving a bit (and it was fully warm), the sound went away.....completely - even when turning the wheel all the way.

Prior to taking the car up to see Doctor Garth, I would get a very low "moan" from time to time and it seemed to be getting more frequent as the days went by. The moan was a "1.5" on the 1-10 scale. The sound I get now (when it is at its worse) is like at least an 8.5. I don't think we had a night that was below -10 until recently, so the "in the freezing cold" symptoms could not be witnessed until now.

In the time I've owned the car (25,000 klms worth of driving), I've never put anything in the power steering reservoir......it always stayed relatively full, even though it was weeping a bit around the hoses. Never any foaming.

.........speaking of foaming, when the ATF foams up, it is reminiscent of the new Tim Hortons smoothy coffees. Looks very appealing, save the whole "tastes like Transmission Fluid" thing.

When I had my 944, it had been overfilled with oil at one point and I was confronted with the problem of removing some oil. Too lazy to get under the car and drain it, I bought a suction gun (for putting fluids in differencials, etc.) and hooked up a skipping rope to the wider hose that came with it and got the skipping rope down the dipstick tube. I can use this gun for the power steering fluid (I just finished cleaning it out).

*IF* I get a chance to do this, I will......and I say "if" only because I enjoy driving the car too much right now. Ever since I got it back from Garth, its like a new car. Very smooth, with so much extra "oommpophhh". It sounds better, starts better and drives better.

Garth was suspicious that perhaps the timing was a bit off from the last timing belt change. Personally, I believe the car now knows it can't "act up" anymore because Garth will kick its ***, so it has given up and decided to run perfectly.

I will do my first flush of the fluid after lunch and will continue the daily fluid flushes everyday until further notified.




Oh, and to Garth for all his help and skill.