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MG TD TF 1500 - Clutch Judder Solved

I may have found the cause of the clutch judder in my TF-1500. What do you think?

A few months ago I posted some videos and questions about my gearbox. One of the problems was a severe judder as I slowly released the clutch pedal at low RPM, especially in reverse. The new 8" clutch and new pressure plate were freshly installed. Moss pressure plate #190-120. The judder caused the worn splines in the rear hub or diff to clack as the clutch rapidly engaged and disengaged.
http://www.youtube.com/watch?v=ZCUTMfcFjKg
http://www.youtube.com/watch?v=MlgvJ1lIEvk

I purchased the clutch and pressure plate in January, installed them in March, and called the Moss Tech Dept in April to explain my judder problem. Moss told me to purchase another pressure plate. I could return the first one if the problem disappeared after I installed the second one.

The new pressure plate was delivered to a club member's shop last month. Another club member was installing a new pressure plate (8" clutch) on his TD at the same time. My friend called to tell me that he found a problem with the new pressure plate on the TD. He asked me to stop by and install my first pressure plate and my replacement pressure plate on the TD's flywheel and judge any differences.

We measured the plate and the housing and we could tell that the "problem" pressure plates on the TD and TF were not in the same plane as the mounting holes in housing. Then when we installed them on the TD's flywheel. The position of the clutch alignment tool confirmed that there was a problem.

TOP PHOTO: The new pressure plate that I installed on my TF in March. Severe clutch judder after installation. Measurements showed that the plate was not parallel to the housing (chalk marks). The clutch alignment tool is off center toward the side that we had measured as too high.

CENTER PHOTO: The replacement new pressure plate that arrived last month. Measurements showed the pressure plate is parallel to the housing. The alignment tool is in the center of the pressure plate. Camera was slightly off axis; trust me, the tool is in the center. I drove the TF with the replacement pressure plate for the first time this week. The clutch is silky smooth. I did not replace the clutch - it is the same new one that I installed in March. The alignment too was in the center when I installed the pressure plate on my TF just like it was on the TD "test" flywheel.

BOTTOM PHOTO: This is the old pressure plate that was in my TF before I installed the first new pressure plate in March. Clutch operation was smooth, no judder. The alignment tool is also in the center. I installed it on the TD flywheel to judge the location of the alignment tool in a pressure plate that is known to be good.

I'm a gearbox newbee, so I don't know for sure that the pressure plate was the problem, but it sure seems like it could have been. FWIW - two of the three pressure plates that we have purchased since January were not parallel with the mounting holes in the housing.

Lonnie
TF7211

image:
Three pressure plates ... bad, good, old (but good)

LM Cook

Having heard your nasty judder in person, I think you found the problem! George
George Butz

I certainly hope you put the final bolt in before you tightened it up.

Or maybe based on the fact that both top and bottom are good, you left the bolt out. :-)
Christopher Couper

For 37 years my TD has a judder in the clutch when backing up a hill but not when going forward from a stop. I always considered this a "feature" of the TD clutch and lived with it without a problem. Is my car unusual?
John Quilter (TD8986)

> Chris - I was hoping that no one noticed the missing bolt! I lost the bolt when I removed the pressure plate in the top photo. So I was one short for the center and bottom photos.

Yes, I used all bolts plus new square lock washers when I installed it on my TF. Thanks for checking with me to make sure.

> George - I couldn't have completed my gearbox rebuild without your help and the help of this forum. Greatest place on the web.

Lonnie
TF7211
LM Cook

Not so sure. The small release bearing plate shown has absolutely nothing to do with the bearing surfaces captured between the flywheel and pressure plate, joined as a single unit. If the tool puts the clutch plate in the center, it's in the center even with an off-center throw-out bearing... or no bearing at all. IF the bearing has been poorly made it will make a bit of noise as it spins but only while the clutch is applied.

I'd look for unevenly torqued pressure plate springs as the major concern for chatter.

Second will be a flywheel and plate that cannot be made perfectly flat to one another no matter the spring(s) tension. As the two turn with the clutch plate slipping between them, a high spot in the clutch plate meeting a low pressure point on the flywheel/pressure plate assy. will slip and grab, slip and grab, slip and grab as the two areas pass one another.... Chatter. This can be caused by an out-of-spec clutch plate fork, perhaps being unable to fully retract the plate.

That is the classic cause of chatter and is remedied by making sure the two surfaces are co-planer across the entire surface.

Wobbly motor mounts will cause bounce bad enough to rattle the shifter amplifying the chatter.

.....
MAndrus

I read through your post again. Sorry, not sure what you tried.

Did you find that the stamping was higher in some areas than others - a crappy stamping? If so, could adjusting the forks make up for the difference, or did that not work?

I might have driven past your diagnosis and cure the first time.

.....
MAndrus

Lonnie: They caught me with my upside down fuse block so I am leaving no stone turned for anyone else :-)
Christopher Couper

John Quilter,
Before you pull the trannie as Lonnie did, Check the rear axle U Bolts to make sure the nuts and locknuts are TIGHT!!!
Loosen the lock nuts first,,, then tighten the inner nut,, followed by re-tightening the lock nuts,,

Also check for wear on the axle where the U Bolts have been "rocking" back and forth..

Steve
Steve Wincze

First of all let me tell you that I had never even seen a pressure plate or the inside of a gearbox until I replaced my first pressure plate last March. So I am a 100% dufus.

> MAndrus - We laid a straight edge across the mounting holes on opposite sides of the clutch cover where the cover contacts the flywheel. Then we measured the distance from the pressure plate (#18) to the straight edge at each mounting hole. The chalk marks on the clutch cover in the top photo mark the max measurement. It coincides with the off-center alighment tool. Don't know if the problem was a poor stamping of the cover, or if the release levers were not adjusted correctly.

If the pressure plate is off axis, would the release plate also be off axis? If so, it seems that would cause the alignment tool to be closer to one side of the release plate.

Section E6 of the TD-TF WSM discusses adjustments to the release levers plate by turning adjusting nuts #14 in the diagram. The release levers should within 0.005" of each other. I didn't have the nerve or the experience to adjust a new pressure plate and void the opportunity to return it.

A cause of juddering is noted at the end of Section E1. See image below.

Thanks for your insight and experience.

Lonnie
TF7211

LM Cook

Steve, This is far too minor for me to be pulling the gearbox and investigating. My father would have called this tinkeritis. Over years I have ensured the U bolts are tight and the car has the saddles on the axle tube to prevent further wear to the tube. Thanks for the tips.
John Quilter (TD8986)

This thread was discussed on 31/07/2015

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