Mike Frye

<<< voted 2 and 3 because I think it should be part of every PPI*


*If it's an auto... I know it's theoretically possible for this to be an issue in a 5 speed, but I've never read about it actually happening and the design flaw that causes it in autos is not present in the manual.



and I do like pie

Cosmo Kramer

I believe that if a PPI is requested on a 928 that it should be part of the process. The problem is finding a shop knowledgeable enough in 928's that can perform this check locally when you are purchasing the car. Many Porsche independent shops are well versed in 911's Boxsters etc. but cannot do a proper PPI on a 928.

Personally I would just find a hoist or pit, throw on the coveralls and do it myself. Not everyone has the ability to do that.

James Bailey

Having spent many many years selling parts to shop owners and talking with mechanics who are working on a 928 and countless owners.....very very few knew of Thrust Bearing Failure until I told them.....besides in MOST cases it is like you are taking a horse to a Vet who specializes in birds...
My solution of course is to simply not buy an automatic....

Bill Ball

That quote is different than saying it is normal for a GTS to have TBF and a PPI should not include testing for it. I can agree with that quote.

IcemanG17

for auto's 100% yes.....I wouldn't worry about it for 5 speeds or early pre 84 auto's

blown 87

so you can agree that a normal PPI would not check for end play???????????????
Because to me a PPI would include a end play check.

blown 87

Bunch of Pie haters here also.

GlenL

I went for pie because that elicited the strongest response.

Crank play is a problem only on automatics, for one thing. You can also gauge the problem by releasing the intermediate shaft and looking at the movement. Much easier than testing the crank. If it does move a lot (and what's a lot?) then proceed to a crank movement test.

Incidentally, 0.005 doesn't indicate a failure. It indicates the need to drop the pan and take a look.

blown 87

That was .005 past the wear limit, not .005 of movement.

You are fooling your self if you think that how much flex is in the flex plate is a good indicator, because it is not, I have seen them sin over .075 of bow and only have .010 of end play.

What very little bow will tell you is that the pressure has been released.

GlenL

Or that there has been no pressure. Ask if it has been worked on and released.

Does 0.005 mean it's through the thrust bearing? No.

SeanR

I like pie.

I've tossed this around in my head a few times. When I do a typical PPI on a car I give the customer a choice. Either it's $150.00 for the basic, 4 page inspection. If I get in to doing a compression check, it is $250.00. And if the person wants me to check the crank end play on a car with stock exhaust, it's another $75.00 on top of whatever option they pic. So either $225.00 or $325.00.

Most people will opt for the basic one that takes me a bit over an hour to go through and have had no one ask me to check the crank end play. I suppose it's just not that important to a potential owner who doesn't know much about these cars. And yes, I do stress the importance of it and if it ends up being a local guy who's car I work on, then I end up getting paid to do it either way.

I know of guys out there that will charge $500.00 for a PPI, and for that kind of money, they damn well better check everything, up to and including the torque on the wheels.

Crazy isn't it.

blown 87

How about .020 like this car had?

GlenL

How much play is there with a new thrust bearing? You need to subtract that from the number to see how much wear there is.

In any case, the thrust bearing faces are thicker than 0.020.

blown 87

It will be into the copper and maybe have some steel showing, I have seen them into the copper at .012.

There seems to be some variance in the thrust bearings or cranks, I have seen enough of them to know that some at .010 look as bad as others at .020.

So subtracting the new limits does not really work in the real world.

I start getting worried at anything over .010 total play, and at twice that, well you are rolling the dice.

Bill Ball

Would and should are two different things. Ideally it should, but since the problem has never been officially recognized except with improperly installed transmissions, and performing the inspection requires dropping the bellypans, front exhaust and lower bellhousing cover, I've rarely heard of it being done pre-purchase. Of course, I would recommend it too with any late model auto box.