Garth S

Following a perfect afternoon of a 300Km cruise through several Atlantic seaside villages, we pulled a hard left ~ 4Km from home - and I felt gravel through the steering - but we were on blacktop! The telltale sign of low PS fluid . Limped it home and topped up the ATF: The pump is fine,and the boots were wet, so I drove for a bit to get an idea of leakage rate. I crawled underneath this AM to confirm the failure - which turns out to be both end seals. Both boots were full of ATF - one of which puked all over my tee shirt before I woke up .
These things never get better, but before trying to select a repair option that says the rack was the problem - was an overpressure of the pump a possible cause?? I ask, because both end seals appear to have identical leaks starting at the same time! I presume the pump is protected from overpressure by an internal relief valve - but do not know.
If the failure is simply old age ( only 63KKm/38K miles) is a rebuilt the better option? I read of optimistic souls buying seal kits, but fewer stories of raving success in home rebuilding - is there a simpler option of doing only the end seals? - or more likely, is it a 'whole hawg' job?
I was holding off motor mounts until a pan gasket arrived - now the rack : Maybe I should stuff the PS pump full of one of these no-leak additives, and drive until I need to do rod bearings - may as well make it a full Saturday! .
Any advice appreciated.

Randy V

Is this on the '80 or the '88?

It does sound unusual for both end seals to begin leaking at exactly the same time.

If it was me, I'd clean out the boots, drain and refill with new fluid and add a seal conditioner additive. It just may prolong a rack replacement for several months or longer.

Thaddeus

Based on my experience with a 951's leaky rack, those stop leaks do nothing. I tried. I replaced the rack shortly thereafter.

Garth S

Whoops, Yes - the '88 S4. I've drained the resevoir several times to flush the system, and have added Lucas goop aka 'snake oil' - "stops leaking and squeeking PS racks" - good point Randy - fingers crossed.

okbarnett

all 928 racks will start leaking sooner or later. they wont fix their selves either. may as well get a rebuilt, or have someone rebuild that one. most power steering and drive line shops have ZF parts to re seal them. Or just order a rebuilt one and swap it.

kaptnknemo

Just finished putting a rebuilt rack in, new tie rods too. Not to hard, Just Dirty! Followed Pirtle's Guide (thanks!). Maybe 6 hours spread out over a week. New resevoir too. Biggest problem was with the universal joint, had to heat it, to get it out and then I put the steering half shaft on before putting the rebuilt rack back in, saved a lot of frustration being under the car trying to get the U-joint to align!

SteveCo

Garth;
Tough luck on the rack leak. Very strange that both seals started leaking at the same time.

I was gearing up for a rack rebuild or replacement last year, as my rack had developed a sizable leak too. I did some work on the rebuild process and even tracked down the all-important seal kit. IIRC, ZF do not sell kits to mere mortals any more...not sure that they sell them at all any longer...something about liability issues. I know that they are available from the Big 3 and eBay has kits listed from time to time. BTW: the rack is ZF Model 7840, if that helps.

Transtec makes a kit that several people have used (www.transtec.com) and I believe you can buy it directly from them. I was able to find a Canadian dealer for Transtec products and they quoted me about $145Cdn + shipping for the kit (Transtec PN: 8320). the dealer was HydraSteer in Edmonton (www.gearcentregroup.com). Contact was John Kociuba at (780) 453-6253.

I'm sure that most tranmission rebuilder would have access to this type of kit in their supply chain as well. I did not check this out, but will when I gear up for the job....assuming I do not opt for a pre-rebuilt rack, that is.

My rack still leaks a bit, but I found that after raising the ride height of my car to factory specs, most of the leaking stopped! This has delayed my rack work until I am ready to do the motor mounts and pan gasket...do them all at the same time.

Let me know if you need more on this. I have assembled info on the rebuild...happy to share it if you need it. No experience with the project yet, though. Maybe you can document your project for all of us? This is something that needs to be added to the 928 online body of knowledge.

Regards,
SteveCo in St. John's

Peter Thompson

I just recently had my steering rack replaced - both seals had developed leaks as well. My mechanic said it wasn't safe to drive it was so bad. Don't let it go too long.

Cheers,
Peter

Bill Ball

Doing the rack and motor mounts together is a good combination since the rack must at least drop down to allow cross-member removal to get to the mounts. The rack is a relatively simple job. Re-centering the steering wheel (despsite the centering dimple on the rack) is the hardest part. Toe-in also needs to be checked post-rack change. WYAIT, the oil pan gasket is a companion task to evaluate since the cross-member must drop to do it - although someone concocted a way of replacing the gasket with the cross-member in-place.

SteveCo

I think Garth was (at least one of) the R&R-the-oil-pan-gasket-in-place concocter(s). Looks like he will have lots of opportunity to combine procedures and evaluate their relative merits! Ha!

Regards,
SteveCo in St. John's

Garth S

A wee bit of an update, as the more you take apart, and the more questions you ask ... did anyone mention Pandora's box? ...
Steering rack: I kept the pump protected with adequate ATF - but both boots filled again with ATF and the assembly grease that racks are packed with ,a clear sign of 'the point of no return'. 'Googleing' for info on racks suggests that if both ends begin to leak, it is highly likely that an internal high pressure seal has failed - and simultaneously causes oil and grease to spurt from the external seals. No reprieve will come magically from a bottle of snake oil!
Priced a 928 rack rebuild kit @$100cdn - and rebuilt "long' racks (w. inner tie rods and boots) from $550 to $1865 - after that, I didn't have the heart to call the Porsche store: instead, I called an industrial supply house, and am having the rack rebuilt at the same center for $260 : it pays to shop!
Since the tie rods and boots are as new, they stay, and I roughly followed the tips in Pirtle's (or was it Nichol's) site - no matter, they're both excellent. A couple points of preference though: only in desperation pick up a pipe wrench to remove the tie rods from the rack - counterhold with a 22mm and turn with a 32mm (7/8 and 1.25" are close). Borrow a compressor and impact gun etc if you do not have one - it is not the speed that counts, it is far superior in releasing bolts that may twist off otherwise. The rack mount bolts can be counterheld from above with a 3/8 socket in 17mm - no prys/allen keys req'd. One point of blinding stupidity (only one!) occurred in removal of the universal joint from the rack input splined shaft: you can pull, pry and tap forever after loosening the pinch bolt - it WILL NOT come off grr: However, if you remove the pinch bolt from the groove that it has in the pinion shaft, the thing will fall off in your lap!
With the rack out, I noticed that the 4 mount bushings were not 'preened over' on the top side - Is this a recommended step?? For those of you who have replaced racks, how did you install the bushings?
So, the rack is gone for a weeks holidays, and will return as new. In the meantime, I have 2 motor mounts and another pan gasket waiting: Not today!

Mattman928

I heard that the GTS rack & Pinion and Pump configuration has much greater power assist.

Is this true?

Will this fit on a GT or S4?

How much of a difference will this make?