slate blue

It will be highly unlikely the block will be servicable. Sometimes the crank is but the shavings thrown around often also score the bore and as we know there is no replacement pistons.

The checking of the position of the torque tube should be a maintaince item. But on the S4 it is quite a job to get the exhaust down so that the cover plate can be accessed. There are specialist mechanics that will check the tension on the shaft as a matter of course. It is something to keep your eye on. The rear coupling bolt is often not tight enough and this can also cause problems.

There has been much debate about the cause of the shaft moving forward, there is not one accepted by all theory as to why it happens. This may hurt your case. But as I mentioned before, if you have had only Porsche servicing the car, well shouldn't they have been responsible for its well being regardless of how this damage has happened. Your case may rest with the arguement that I was paying you as the experts to know what to do.

As to a court case, may be very costly if you lose, you might lose too. Never go into these things blind, thinking you can't lose, the courts have been full of people like this. Fair Trading is a much better option as you wont have to pay anything really if you lose. The down side or maybe upside is that they don't allow lawyers and press both parties to settle the claim. Some money is better than paying Porsche's legals. remember if they want to fight, they will, and with the backup of the factory engineers they will probably beat you. Strange you might think but I have seen it happen in other cases. remember who is paying the engineers wages and the courts often go with the best qualified expert witnesses.

Cheers Greg

Daniel Dudley

The 928 is a complicated car and there are darned few dealers who still have factory trained mechanics qualified to work on them. The smart dealers will promptly admit it. The time has come for tou to consult with a Lawyer. If you don't have one, consult with some of your most powerful friends and contacts. A shark for a shark. If you lived in the US I would tell you to consult with the Atourny General.
Don't give up ! You have right on your side. The question is, do you really think these clowns can swap blocks on your car? Do you think they would take the time to get it right, or make it right? The biggest problem I have found with 928 ownership is the people who work on them. Find a good Mechanic you can trust Before you do a lick of work on that engine! We are all with you on this.

atb

The drive shaft can move forward in the TT by the force of installing the tranny on the rear splines. I understand the shops "defense" that if the notch in the in the drive shaft lines up with the notch in the rear flex plate hub upon installation of the tranny, that must prove that the drive shaft didn't move. I still think its potentially bogus though. I think its very possible that in removing the tranny they pulled the driveshaft rearward through the bearings (and the front pinch collar), and then on reinstallation, pushed the driveshaft forward again, in such a manner as to exert pressure at the front flex plate. Unless the shop has proof positive that they released the pressure at the front flex plate hub after installation of the tranny, I think they aren't totally in the clear.

Bill Ball

So, they are saying that a 10MM preload on the flexplate was pre-existing when you brought the car in. Ew. Yes, adjustment would have relieved that, but that is enough pre-load to have done harm. Most observations are that under normal driving conditions it is common to find about 3MM of pre-load when the clamp bolt is loosened. Anything more than that is worrisome. How fast would damage occur? Dunno. Although the real cause of this pre-load is debated, other than improper tranny reinstallation, others have suggested expansion of the torque converter, movement forward of the torque converter due to torque converter bearing wear, TT shaft stretching, and.... So, if they have records of reporting a 10MM pre-load to you before the work was started, your position may not be very strong anymore.

Sab

I think there was a service bulletin by the factory telling the dealerships that if they screwed up a tranny install and ruined the block, it can not be turned in as a warranty claim after...

Garth S

Victim ... to be a bit more upbeat for the long term, you may wish to create an early name change: we do not wish you to be a victim forever .... However, in this situation, it clearly appears to be the case: to prove liability will be difficult. If that can be reserved for later, what are the facts and potential assembly errors that could have led to this TBF situation ....
Before a transmission issue, you appeared to have been well satisfied with a fine running '89 S4. A Porsche service dept. was contracted to effect repairs. Since the car was first returned to you, apparently it never ran correctly - and the Porsche dealer retained more time in custody than you did over a three month window ( which may include the initial repair time?) ... until it died of TBF. Is this reasonably accurate?
Subsequently, the Porsche folks told you that the TT prop shaft had an ~ 10 mm forward positioning that they were not responsible for ... and that TBF was real, and entirely your problem: "Please pay us a lot of cash and be so kind as to not slam the door as you F-off".
Furthermore, they quoted in their defense WSM 39-141 (circa 1984) that states, in reference to distance 'X' on the prop shaft forward shim stack .... " this adjustment is not necessary after replacement of transmission or transmission parts"!!!
By now, you are well aware that the S4 cars do not use the shim stack, bushing and locking circlip to establish distance 'X'. Despite this, even PET 6 still shows the bushing and circlip present of '87 up cars ... I doubt this to be true: has anyone seen these parts on later prop shafts on the engine side of the front flex plate?
The key point here is that management of crankshaft end float/preload is no less important than it was at the time of the WSM being authored in 1984; however, the technique of doing so has changed. With the 'S4 family', the front pinch bolt must be released to allow the elasticity of the front flex plate to find its null point. It has become common practice ( I hope) that this step is followed on every auto transmission reinstall. There is no specific Service Bulletin nor Tech Note that I could find indicating this: again, does anyone know of such a written statement from Porsche? This documentation would be crucial!
This dealership have wrapped themselves in the single statement of 39-141 noted above - and say they could have done no wrong .... and unless there is some written data to allow for the deletion of the shim stack in the S4 cars, it will be difficult to prove otherwise!
So, what else could have occurred to jam the prop shaft too far ahead? Well, three things come to mind.
If the transmission was reinstalled only partially on the prop shaft - and the rear pinch bolt installed just to the rear of the shaft end rather than in the groove, then the prop shaft has the potential to be driven very far forwards. I do not know if this is feasible.
Prior to installation of the transmission, WSM 39-139 specifies a rear prop shaft protrusion 'A' = 2 +/- 0.5mm. Were there a preexisting condition of the front flex plate being 10mm too far forward ( I'm not sure that is even possible, for I've only seen 3mm, and heard of 5mm as otherwise noted), would not the extreme spring pressure caused by this deformation try to correct itself when the pressure was released at the rear end? - namely, when the transmission was removed! It can't take too much pressure to achieve at least some axial movement of an otherwise freely spinning prop shaft, suggesting that the 2mm WSM specified protrusion may have been difficult to achieve on reassembly. Thoughts?
Thirdly, the subject of torque convertor installed depth: In WSM 32-104, it states that up to MY '86, install convertors to ~ 16mm depth in the case. For MY '87 on, this dimension changes to ~ 28mm .... an obvious 12 mm change. Later on in reference to actual convertor installation, WSM 37-139 , point #7 clearly states that " measure installed depth of convertor( ~16mm) and note value for reinstallation." So the question is ... if it were possible to install the convertor in a S4 transmission at the wrong depth following a blind misread of the WSM, could the prop shaft be driven forward ~12 mm too far? - or at least far enough forward until the front flexplate bottomed out against the flywheel causing the prop shaft to forcibly slide through the splined coupling??
So much for speculation as to how one could screw up - my head hurts ... and this is too long. However, if we focus on this issue a bit, perhaps a real gem will evolve from those who actually see and do S4 transmission work - maybe a real service bulletin that was ignored ..

Steve Cattaneo

Central tube installation bulletin dated 1992 # 9203
After the central tube is bolted to the forward housing, first tighten the six-drive plate attaching bolts to 23-28 ft lbs. Then tighten the clamping screw (new one) to 54-62 ft lbs. Following this procedure will ensure necessary running clearance for the crankshaft thrust bearing. Any damage to the engine which has been caused by improper central tube installation is NOT a warranty mater.


This is the only bulletin addressing thrust bearing failure. It does not mention transmission installation, we know from experience that the front clamping bolt should be loosen after or before installation of a transmission to relieve any crankshaft load on the TB.

SharkSkin

Some good stuff there, obviously the musings of a thoughtful and careful man.

But...

Common shop practice is to bag & tag all parts, or thread things back together if convenient. Now this is kind of a nightmare scenario, granted... but there is potential to find evidence of the mistake if it occurred:

Suppose the monkey putting it back together left the pinch bolt in the collar on the trans as he went to reassemble it. Suppose further that said monkey discovered that the transmission would not slide all the way back on easily and decided to force it, maybe even by pulling the trans into place using the bolts on the TT flange. Suppose he then simply tightens the pinch bolt and says, "done"! This would put a LOT of force on the TT, flexplate, crank, and thrust bearing. Enough to cause all of the bad things that have been discussed IMHO.

Symptoms of this that you might be able to detect after the fact are munged bolt, collar, center shaft end. With the car on a lift you can easily see the pinch bolt. Is it new? Well, actually it should be -- but if it's old then that's one thing they did wrong. If it's old it should be pulled out immediately and inspected; if it's munged then suspect the worst. If that bolt is new, then you won't be able to prove or disprove this theory without separating the trans and TT.

P.S. I don't know how the laws work over there, but over here if a shop does $25K in work that was never authorized by the owner, legally they are obliged to eat it(AFAIK... maybe there is some finer point that I'm missing). What did you sign, exactly?

victim

Thanks again Mates. It's good to have mates when you're down. Hey Garth I'm open to suggestions what do ya reckon? "Victim Bites Back"? "Injured White Pointer"? "Shafted" ?
Hey Bill let me explain; they said after"stripping down" engine they discovered the crankshaft had seized and "almost worn" into block. On request they only produces a nail-sized sliver of the bearing. They said the cause of all this was "misalignment of crankshaft to drive shaft causing excessive load on rear crankshaft bearing.." When asked what this "misalignment" was they said 10mm.
Can I ask anyone how they measured this 10 mm AFTER STRIPPING DOWN ?? And since it's not a shim design how do they come to conclusion that the cause was previous engine work BUT NOT after or during their TRAN work?? PLEASE HELP ME OUT : If there was preload (say 10mm) wouldn't the shaft travel rearwards when the tran is removed ( i.e. flex plate relieved)?? Everyone knows it does move. No? It can also move, as one of you mates above said, accidentally while removal of tran.
The point is they should check on refit NO? Load or no load. Esp when this TBF prob is not uncommon with the 928. How can this happen but in a F--up. Apprentice? Not much experience?
Thanks Sab are you saying bec there's no warranty theyre in denial?

It's one thing for them to take that stand but how does the Pointer feel when he's lost the baby shark??? It hurts more when I know NO ONE has opened up the engine prior. A 10 mm preload would've wiped out bearing quickly - WOULDN'T YOU KNOW SOMETHING WAS WRONG? - idle, torque etc -like I noticed after the tran job.

PLEASE GUYS PUT SOME TECH NOTES AND BULLETINS DOWN MY WAY. I shall not rest - 25,000 or not. Lets Fight On....

Bill Ball

Yes, they would have to measure the preload before removing and stripping the engine. You measure the preload by laying a straightedge across the flexplate and measuring the bow (not accurate unless at the center somehow) or you measure the front clamp movement down the shaft when the clamp bolt is loosened.

It's a bit hard to piece together the sequence of events from your description, but if they found the excessive preload not too long AFTER they did the trans work, then it is clearly their fault since that must be set as part of reinstalling the trans. The TT and trans are usually dropped as a unit since it is hard to get to the top rear TT bolts up in the tunnel. So the front bolts, and the clamp bolt are removed and the TT goes down with the tranny. Hence when reinstalling the tranny with the TT, the front clamp bolt is one of the last things you tighten. If somehow they removed the tranny and left the TT bolted to the bellhousing and the front clamp untouched and then reinstalled the tranny never checking the front clamp, there is the boo boo.

Tails

To get the the most conprehensive lot of technical information relating to your 928 for your case with PCM, I would suggest that you obtain a set of Jim Morehouse's Technical CD's. These CD's contain copies of the Workship Manuals, most published information, specalist procedures and all Technical Bulletins notification made by Porsche regarding the 928's into North America.

You will need all of this technical information to build you case whether you fight them yourself or use a lawyer. On your current presentation you have what a QC once said to me on a major case I was involved in "at first blush we have the better of the argument". Don't forget if you go to court it always turns out who has the better of the argument supported with documentary sustainable evidence and you will need to brief your lawyer on the technical issues as usually they have little or no technical engineering expertise. I would suggest that you sit down and make a full diary note of all the events, with time and dates and what transpired at every meeting, who was in attendance with full names and titles, if you have not already done so. I would also get together the full history of your car with receipts etc., so as to prove that you were a competent owner of such a sophisticated piece of automobile. The more information you can gather with documentated proof together with Statutory Declarations etc., if needed the better prepared you and your brief will be.

I have a full set of these Technical CDs and they are invaluable in maintaining the vehicle.

To get a copy, put a note on the Rennlist 928 Forum and ask Jim to contact you at your e-mail address. There used to be a contact in South Australia who could send them to you at a very very reasonable cost. If this source is still available Jim will advise you of contact details.

With regards to the engine thrust bearing failure, Porsche issued a Technical Bulleting, Subject:

Installing Central Tube Number 9203 dated 6th May 1992 wherein they outline the procedure for installantion of the Central Tube.

Models affected: All Model Year 928's with automatic transmissions
Concern: Installation procedure of central tube
Repair information: After the central tube is bolted to the forward housing, first tightne the six (6) drive plate attaching bolts to 32-39Nm (these are the bolts attaching the flex plate to the ring gear of the engine). Then tighten the clamping bolt to 75 to 85 Nm. Following this procedure will ensure necessary running clearance for the crankshaft thrust bearings.

Porsche then stated: Any damage to the engine which has been caused by improper central tube installation is NOT a warranty matter.


You mentioned that the automatic transmission had been removed for repair and only after installation did your troubles commence.

The Workshop Manual page 39 - 139 it indicates that the under section "Checking Central Tube" on its replacement that the "Position of the central shaft and rear flange shaft is important to guarantee proper functioning. The distance between central shaft protusion and rear flange must be 'A' = 2mm plus of minus 0.5mm" .


Good engineering practice would dictate that when the automatic transmission is removed (was it replaced with a new transmisson or was the transmission repaired and replaced? If the casing was new then this may have an effect on the clearance relating to the preload of the flex plate), in any case, it would have necessitated the unclamping of the aft clamping piece, which has a fixed location via the clamp bolt onto the drive shaft of the central tube. Upon re- installation the clearances at the front and the rear of the central shaft should have been checked. In other words was the clearance 'A' within specification tolerances and was there any preload imparted to the flex plate? that is was there any load or no load being applied to the engine crankshaft?
This is especially important with Porsche's knowledge of the migration of the front clamp piece towards the engine causing engine thrust bearing failure on some automatic transmission models. It is noted that to adjust the "A" protusion Porsche recommend gently hitting the end of the drive shaft with a plastic mallet. Could the Porsche Specalists Mechanic/Technician have hit the drive shaft forward throught the the bearing of the Central tube and preloaded the flex plate and then not checked it recommended no-preload?

Could there have been an initial preload due to migration and if this was not checked and the aft protusion of the drive shaft was greater than 'A' and not checked, so upon installation of the auto transmission, the drive shaft could have preloaded the flex plate once the central tube was tensioned up to the automatic transmsiison flange and the preload of 10mm may have come about. 10 mm is a lot of preload and would not have taken too long to cause the thrust bearing to fail.

With Porsche's information that no preload is now required on all automatic transmission since 1992 the positioning of the front clamping piece and the protusion of the drive shaft aft should have been checked and should also have have been a requirement of the re-installation procedure, as Porsche's technicians are technically trained as specalist and you pay for that expertise. No hit and miss re-installation here please!

I would request from PCM that you be given a copy of the work procedure documentation used for the re-installation of the transmission, a full detailed description of the engine strip down and rebuild together with clearance recorded etc. If Porsche are unwilling to give you a copy, then if you go to court, whether it be arbitration, mediation or a legal procedings you or your brief should receive all documentation from PCM of what they will be presenting during the case and you should be reguire to give copies of all your information, as it will be decided on who presents the best supported argument.

If the procedure cannot be supplied by Porsche or they do not have a procedure showing the clearance and alignment to be checked during the re-installation then this should be a clearly case of negligent on their part (This procedure should itemise the steps, the alignment checks and the clearance to be checked etc). If they do not have a procedure and it was done on local knowledge and expertise then they could still be negligent as this a highly sophisticate piece of engineering fit up and should not be undertaken on knowledge and experience alone, this is why Porsche issue there Technical Specification Books detailing all clearances, torque setting etc. (Remember the initial cost of the 928S4 in Australia of your model was A$236,000).

To check whether any preload or migration of the front and rear clamp pieces should have taken approximately 1 to 2 hour only. You may consider asking if they checked the forward and after clearances after the last repair?

For your information in checking my car's front clamping piece, when released, it had migrated the clampiece of 3.08mm. I checked the end play of the thrust bearing and found it to be 0.20mm with Porsche giving an end play tolerance of a new bearing as 0110 to 0.312mm. Upon reassembly I moved the crankshaft aft until it abutted the thrust bearing and then tightened the clamping piece to the upper limit of the torque specificied by Porsche to give it the maximum forward play prior to experiencing any preload. The clamping piece was then sprayed with silver paint so that yearly inspections could easily see whether there was any migration.

I have stated this as Porsche automative engineers/technicians would have known of the problem, as there has been failures of the engine thrust bearing, otherwise why did they release Technical Bulleting No. 9203 listed above.

In America there have been after market fixes to this problem. Some apply locktite after tensioning the clamp bolt by an extra 10% as suggested by Porsche and there is another by fabricating a new design of clamp piece with a tapered flanged collet piece. The flange is bolted to the clamping piece so when it is tightened it give a better 360 degree clamp to the drive shaft.

I note in you latest missive to the forum that they said that the aft bearing was out of alignment by 10mm, can you clarify whether it was the thrust bearing or the aft bearing? was it preload on the thrust bearing or was it axial out of alignment of the aft bearing? as this will make a lot of difference in what actually happened or could have caused the failure. The thrust bearing is located in the centre of the crankshaft, however if the aft bearing was being forced out of alignment by 10mm then the engine could have had a catastropic crankshaft failure and would have run most of the bearing at the aft end of the block as the crankshaft deflections would have been massive.

I would suggest that it is nigh impossible for the central tube to be out of alignment by 10mm, as the engine, central tube, auto matic transmission and transaxle are bolted together as a single unit with machined faces located by sleeves at the bolt holes as far as I can see on the drawings.

I hope that the foregoing will help you with your endeavours and don't forget to "gently" remind PCM that you could be fully detailing all of you concern, problems and outcomes on the various Major Porsche Web Forums around the world, including Landsharks Australia and the Porsche Clubs in Australia. You may even consider to initiate your own web page outlining your problems, however don't forget that Porsche are the most successful car manufacturer in the world and are quite touchy regarding their reputation and image, let alone they make great motorcars.

I hope that all works out well in the end, but I don't like the fact of the $25 per day parking fees, maybe the gentle suggestions may have an initial effect of getting some reason into the argument.

Tails 1990 928S4 Auto

Sab

Hi Victim,
what I think it proofs, is that the factory already told all their dealers to be careful on work that involves the torque tube and that if they screw it up the factory won't honor any possible warranty, but rather the dealership has to pay for it. Since you don't have your car under warranty that does not help you directly, but I think it makes it easier to proof that you are not alone with this issue but rather that it happened often enough for the factory to warn their dealers.
Good luck,
Sab.

victim

Hi Friends its 3 am on a wintry day Down Under and my eyes are bleary especially after carefully reading Tails' captivating expose. Those are invaluable points to throw at them and then use it to cruxify them. Thanks Tails. Except Mr GM at dealership told me not to contact them anymore. I will hear from his lawyer. And the Service Manager has long refused to put anything in writing although he did ask me not to go listen to cr-p around the traps. They would explain to me - if only I would sit down but no writing please.
When I asked what they wanted to explain - that the drive shaft cannot move? He said yes, or otherwise the clamps with their bolts would not fit. When I said everyone that I had spoken to ( and more than one person in the same building ) had told me that it moved easily he said he didn't care what the whole of Melbourne thinks.
I then said there must be play and tolerances even if the grooves and bolts must match. His reply was, but the "misalignment" was as big as 10 mm. Someone must have fixed your car in the past and made the error.
I asked, so what about when the sump was drained 3,000 km or five months before tran repair? Wouldn't there be signs? Shavings? Yeah but it dropped into the BELL HOUSING in the rear ( so no sign of bearing wear in the sump tray). Sharkskin Dave and Daniel many would tend to agree with you what you said about funny creatures. I couldn't help laughing!

The report had stated, "STRIPPED ENGINE AND FOUND THRUST FACE OF CRANKSHAFT SEIZED. DETERMINED CAUSE DUE TO POOR ALIGNMENT OF CRANKSHAFT TO FRONT SHAFT, THEREFORE PUTTING EXCESSIVE PRESSURE ON REAR CRANKSHAFT BEARING AND FAILING OVER TIME. "
When asked if "front shaft" was in fact the drive drive shaft in WSM drawings the man took the report into the workshop and came back 5 mins later and said, "yes, correct." So, i dunno if it answers your question Tail, but the damaged bit was the thrust bearing. Just how someone could've messed up distance X while doing (non-existent) engine work (as they are claimimg), I am still trying to figure out.

Stay tuned....


And thanks Steve for the constructive note (and Tech note). Garth you've covered the points methodically.

SharkSkin

Again... did you approve the work? What exactly did you sign?

victim

Sharkskin,in short, no. Sorry I wasn't ignoring you - there's so much to absorb so much figuring out to do and I have to run a restaurant as well. When they told me the car had seized my first reaction was sure, you guys had better fix it up; everything had happened right there in your workshop :-

I went in for recommended trans repairs, you gave me a bill for 7.5 k and the car was not driveable. Then three months of adjustments later ( I lost hope the car was ever going to be what it was again ) all the torque was gone when it warmed up - but it had enought torque to limp back to the garage and when i switched the ignition off then on again it would run again. On this point I remember reading Vilhuer's post in the thread Thrust Bearing Failure? in the 928 Forum ( 02-02-05). He mentions, " restarting right away wouldn't be so surprising as start motor could push crank just barely and free it. "
So it went back to the garage and they said, Good! ( thinking the prob was solved ) They said it must be some sendor that senses the exhaust hence shutting down one bank of the engine. But when the sensor arrived from Germany they said nope, it didn't work. A few days later they said the engine wouldn't work at all. Then they said they would open it up to see what had happened. Later they said the crankshaft needed repair and I told them they had better fix it up,' that I was really disgusted with the whole affair that everything had happened at the w'shop and went from bab to worse. My stand was you stuffed up so you better fix it up. There was no quote.

In hindsight I would've done it differently but at the time I wss just sick and tired after three months of trying to convince them that the car was not right. Until it blew in their faces. I Knew there was a connection but I never expected them to put the blame on me!!!

I have a question for Tails. You mentioned, Good engineering practice would dictate...Upon re-installation the clearances at the front and the rear of the central shaft should've been checked." In other words dist X and dist A. Others have mentioned similar requirements :
Bill : "...that (preload) must be set as part of reinstalling the trans. "
Someone also talked of "warnings".
Are there actual notes on this? WSM? Bulletins? (I will get a set of bulletins from Morehouse.)
Can someone point me to the right places in the bulletins?
At the end of the day black and white is what matters; I need written stuff.