touay001

Happy new year to all,
I have performed the loctite fix few years ago. The car was of the road most of that time (long story I will start a different thread). I got the car started after some issues with the fuel and the electrical systems. During the oil change I checked the flex plate for any movement, and sure there is a 2mm movement. I was surprised. The loctite 290 suppose to stop the movement of the shaft. Anyway, I removed the pinch bolt, but the flexplate didn't spring back as when I first done it. I have tried heat (botan tourch), WD40 and trying to pull the hub back but it wouldn't budge. It very hard now to confidently check the end play. I can hear the clunk moving the crank to the back since I have enough leverage. My end play measurement is about 0.2mm. What can I do to move the hub and release the flexplate? I'm thinking to drop the TT and do Constantine's super bearings and super clamp.

Speedtoys

...why does everyone put WD40 on stuck ****?

GregBBRD

Loctite is Urban Myth.

Constantine showed it didn't work in his initial testing....

JET951

Have you checked the rear ( of torque tube ) coupling bolt , thats the one that always stretches and allows the migration of the T Tube shaft forward , the front coupling is almost never the issue

Remove the rear coupling bolt ( while the front coupling bolt is out ) , reset the shaft back to the central position & install 2 X new factory index bolts ( light grease on threads) & torque to spec

Do not install any form of Loctite

Recheck( re-torque) the rear coupling every so often depending on usage , meaning if you do quite hard acceleration starts , then check it more often ( its very easy to do )

We have been maintaining these for a few decades now with zero issues

Jerry Feather

If you can't pull the flex plate hub back on the shaft because of the loctite, where is the 2mm of movement?

touay001

Thanks, that makes sense. I'll check the rear coupling today.

ROG100

Far easier to use the Ritech clamp. Does not require removal of the TT. It stops any further movement.

touay001

Hi Jerry,
The flex plate is bowed determined by a straight edge. The first time I did release the front coupling bolt(5 years ago), the whole flex plate assembly sprung back with authority on the shaft. To be honest, I didnt rechecked the flex plate with straight edge after I released the tension back then. When I checked the flex plate this time, it was bowed by approximately 2mm. When I released the front coupling bolt, nothing happened. The flex plate is still bowed about 2mm. I have done approximately 2k miles after the loctite fix and before the car went off the road for 5 years.

touay001

Thanks Roger. I came across this clamp during my search. My problem now is how to get the flex plate back to be straight (un-bowed). I'll be doing the rear coupling check today and hopefully I'll be able to achieve that.

Mrmerlin

whats more important is if the crank is preloaded,
the previous preload may have bent the flexplate so its permanent .
SO can you pry the flywheel back and forth and it stays where you pried it?

Or does it move forward again when the pry pressure is released?

If the shaft will not come free of the front clamp then I would install then middle clamp bolt then use a prybar and block of wood and pry the clamp to the rear,
this should move the whole drive shaft
NOTE make sure the rear pinch bolt at the trans is loose to do this

I would suggest to use loctite on the bolt threads only.

Reason being if the bolt should work its way loose ,
major damage will occur if the bolt should come free of the clamp.

I have seen this happen and loctite used on the bolt threads would have prevented it

touay001

When I let go of the flywheel it does move back. It is definitely preloaded.

Mrmerlin

use a map gas torch on the coupler and heat it to about 250 degrees,
this should break the loctite free

touay001

Update!
I have removed the back coupler's bolt and the shaft moved back and there is no more preload. I measured the end play and It's ~0.16mm-0.17mm



So my humble analysis, the loctite actually stopped the tube moving forward inside the front coupler. The tube had moved inside the back coupler forward and caused the preload on the flex-plate. As soon as I removed the back bolt the shaft moved back by the force of the flexplate releasing the preload. The question now is, don't we need to address the two couplers not just the front one? Do the aftermarket clamps stop the preload on the flexplate even if the tube moves in the back coupler?

JET951

Like I mentioned , its the "rear" of T Tube coupling that is the issue

Make sure you replace both bolts with new ones ( they are an inexpensive Porsche part )

There is NO aftermarket "Rear" of Torque Tube coupling device , its mainly because there is no room for one

Its not a perfect design , the 968 ( last of the 944 series ) had the perfect design , two solid splined shafts coming together ( rear of T Tube ) and a female sliding sleeve over the top with 4 , yes 4 of the index bolts that the 928 has , poor old 928 has to put up with one bolt , but it can be maintained , its just something that we check on major services ( no big deal in the end)

I have been talking about this subject for years & years & years

Regards
Bruce Buchanan
Buchanan Automotive

touay001

Thanks all. Bruce, removing the rear bolt really helped! I guess now every service I will check and relief the preload if it cannot be eliminated.