checking my flex plate and thrust bearing

[Swandog64]

So I got the new shop up and running for the 87 928s4. I got it up on stands and I released the preload on the flex plate. It moved about 1/8 of a inch when i loosened the bolt. I was expecting to find a allen bolt on the clamp, but found this 13mm bolt. Did the factory ever put these in (see pic) ? I just order the PKlamp and will install before it before closing it up.

I had a real hard time getting a accurate measurement using these digital calipers. I couldn't hold them still enough. Any suggestions?

The last picture is a broken ,I believe its a vac line on the passenger side exhaust manifold: Where can I buy a replacement?

[Mrmerlin]

on the last picture you need to remove the cap nut and try to remove the broken off piece of tube then get a ball bearing ACE has them and put it inside the cap nut and put the capnut back on this is a test port that isnt used so it can be removed..
For the flex plate clamp bolt you need to get the correct cap screw its a 12.9 grade bolt,
buy one from a vendor,
also make sure to check the torque of the rear pinch bolt at the transaxle they are very often loose use blue loctite on both of the bolts and torque to 66ft/lbs

[Swandog64]

Thanks Mrmerlin

[Mrmerlin]

Roger that Dog!

[Wrentham636]

Looking good man, like that color.

[Landseer]

Digital caliper is the wrong tool.

I went to Harbor Freight and bought a digital gage for measuring end play.
Gauge and magnetic base w/ adjustable slides should run sub $60.

[Swandog64]

Thanks, I figured I would give it a shot with the caliper. I'll check out Harbor Freight.

I just recieved my PKlamp in the mail so I'll be installing that while I'm in there

[Swandog64]

I came up with this reading 5 times.






Looks good to me!

[Sapientoni]

I don't know why you are measuring. I'd take the bolt all the way out of the clamping end, loosen or remove all the flange bolts, move it back and put some axle grease or never seize on it to prevent corrosion, then bolt it back up, and torque that clamp bolt in it's relaxed position. Maybe run the engine a second or two in park to let it find it's sweet spot. Then torque the clamp. Just be sure it doesn't look like the flywheel is warped or loose. Rusty dust would be an indicator of that.

[Sapientoni]

Originally Posted by Sapientoni

I don't know why you are measuring. I'd take the bolt all the way out of the clamping end, loosen or remove all the flange bolts, move it back and put some axle grease or never seize on it to prevent corrosion, then bolt it back up, and torque that clamp bolt in it's relaxed position. Maybe run the engine a second or two in park to let it find it's sweet spot. Then torque the clamp. Just be sure it doesn't look like the flywheel is warped or loose. Rusty dust would be an indicator of that.

If the flywheel was bowed and you suspect thrust bearing damage, forget the above. If you're just being cautious. BRAVO! to you!!

[Landseer]

Crankshaft endplay check.
Quite important on 928 due to design.
No grease. Add auxillary clamp.

There have been instances of folks correcting the preload on a near-dead car, then quickly flipping it to unsuspecting buyers.

[Mrmerlin]

Sapientoni a few things to consider,
first adding any kind of lubricant to the splines will reduce the effective clamping available with the stock clamp so leave the splines dry.

Next loosening the flex plate isnt necessary just remove the front pinch bolt then the flex plate can find its home.
pry the flywheel all the way back after your done measuring then clamp the pinch bolt to 66ft/lbs use a drop of blue loctite on the bolts threads.

NOTE Prior to clamping the front pinch bolt the rear pinch bolt must be checked and re torqued as they are usually under torqued

NOTE ^^^^^if this isnt done then checking the front bolt is a waste of time as the shaft can still move forwards and preload the thrust bearing.

A quick way to check for engine damage ios to pull the dipstick and drip the oil onto a black piece of cardboard look at the oil in the sunshine if there is metal you will see it this is a quick way to see if there is thrust bearing damage.

TBF is usually attributed to the 32 valve engine cars, the earlier cars had a slip ring assembly

[mproseusa]

"TBF is usually attributed to the 32 valve engine cars, the earlier cars had a slip ring assembly" quote from MrMerlin.
Does the above statement mean that the early 16 valve engines are not susceptible to the TBF? I've really been dreading doing that job.

[Swandog64]

Mrmerlin... so after checking the crank endplay.... I torqued the clamp down and put a PKlamp on. I did not check the rear. Do I have to go back and undo the front before I can check and retorque the rear?

[Mrmerlin]

. I torqued the clamp down and put a PKlamp on. I did not check the rear. Do I have to go back and undo the front before I can check and retorque the rear?

The correct procedure would be to loosen the front pinch bolt,
then inspect the rear pinch bolt.

NOTE You may wind up having to move the driveshaft front to back to recenter the rear pinch bolt,
and you cant move the shaft if the front bolt is tight.

that said try loosening the rear bolt and see if will come out,
so you can see if its damaged on its shank

IE remove it to see if its damaged,
it can be damaged if it was loose,
then either replace the rear pinch bolt,
or tighten it,

then tighten the front bolt after you pry the flywheel to the rear of the car

[Swandog64]

Thanks MrMerlin...I'll check it out.