Clutch chatter...again

[Karl71]

Hi all,
I'm Karl from France (sorry for my english) and used to read your forum for a while.
I own a 66 convertible for 1 year and had a coupe before.
My 66 vert has been concours restored by the previous owner 15 years ago and most of parts are new or restored. By new, I mean 15 years old but the car stayed in a garage and trailered to shows.

The car is a 4 speed manual (BW T10) and 2.8:1 rear end ratio.
My main problem is clutch chatter which can be very violent shaking all the car that occur in 1st gear and reverse only and more when car is hot.
We only drive manual cars in France and I think the issue don't come from my way of driving!

I just changed the "old" LUK clutch / bearing / pilot with a premium RAM clutch and the problem still occurs! It's even worse because the RAM clutch results in a harder pedal effort...

Motor/trans mounts are ok (15 years)+ not any leak from behind the engine + no play in Z bar + pilot bearing is new + flywheel is 15 years old but looks new and flat (I checked it) + new clutch + no play in u joints or rear end + rear springs have been restored 15 years ago (dismantled and repaint)

I'm wondering if this chatter is normal on this car and if I must live with it?
I must tell I've read all the existing posts from internet on the subject but can't find the solution to the problem.
Thanks for your help.

Karl

[gjz30075]

Looks like you have most of the causes covered. What fixed mine was excessive crank endplay. Mine was about .020".

BTW, no it's not normal to have clutch chatter.

[Karl71]

Thank you Greg for your reply.
By endplay in crankshaft, you mean from front to rear or a vertical play?
I don't remember any play in the crank but maybe I should check again...

[gjz30075]

Front to back. It can be checked by moving/prying the balancer back and forth. If the restorer rebuilt the engine properly, this shouldn't be a cause, but doesn't hurt to check.

[mustang656man]

u didnt mention the clutch support/bushings under the dash-clutch spring under the dash must be removed to check for any play there. wes

[gwstang]

Did you happen to have the flywheel resurfaced? When replacing clutch pressure plate/disc etc, I have always have the flywheel resurfaced as it can warp or have hot spots on it and cause clutch chatter. Forgive me if you already did this and maybe I didn't read it in the message.

[beechkid]

True if the flywheel has hot spots, etc it can cause clutch chatter, but any fluid contamination on the clutch disc can cause that as well.....any Brake Lining cleaner will work well to eliinate that potential issue and should be used on the flywheel as well.

But here is my gut instinct.....
1. the flywheel needs to be re-surfaced (not always required for a routine clutch replacement, but one that should occur to ensure things are perfect)

2. I am not a fan of Ram or McCleod Clutches, they both have disc & pressure plate quality control issues. I know I really hate to say this, but I would recommend speaking with a company I have bought (and had rebuild) my clutch assemblies for 30+ years....their prices are less than what you have spent, there quality is excellent, they like to speak directly with their customers regarding what issues they are having, how they use their car, etc......
Clutchmasters
267 E. Valley Blvd. Rialto, California USA
909-877-6800

[Karl71]

Thank you all.
I don't know any clutch specialist here in the french country and won't send my clutch in US for repairs!
About RAM and for a stock car, the pressure plate is too hard on pedal and the previous LUK pressure plate was a lot softer.
The flywheel looked like new without any hot spots so my mechanic guy didn't resurfaced it and it's maybe the problem.
I drove the car back to my mechanic because I was not happy with the result. He told me yesterday that he made the flywheel resurfaced (they machined 0.008") and he changed the pressure plate (he put the old LUK pressure plate which was softer but kept the new RAM disc which was the same and matching size).
I get the car back this afternoon and let you informed if the problem is solved, I keep my fingers crossed!

[MrRon1]

fingers crossed

[68RCodeConv]

"More when the car is hot" means it is probably hot spots (warps) on the flywheel. Resurface it or if it has visible cracks then get a new one.

[lunarweasel]

Hope it works out!

[Karl71]

Flywheel resurfaced + new RAM disc with previous LUK pressure plate and bearing:
Still chatter
My mechanic think it is what you call "wheel hop" and told me to change leaf springs: we can see them shaking a lot while chatter occurs.
I tried to clamp one leaf with a "clamp" and a plier but it did not make such difference.
Strangely, I was doing road tests "stop and go" on a small hill with clamps on the right leaf and shudder finally stopped...?
I decided to remove the clamps to see if any difference and still no shudder?
I took the car 2 hours after and shudder is back
Can't understand nothing.

[Karl71]

Keep inquiring about my problem.
I made some solid clamps of steel blocks and 2 screws for each side.
Put the clamps on each rear leaf spring, between axle and front of leaf, clamping 3 leaves.
the chatter is still there and maybe worse!
I just ordered new 4 1/2 leaf springs from Grab a trak but I wonder if it will help...
Clamping the leaves to make them harder so they don't get out of shape while reving is not the solution on old leaves? Do you think new leaves can work better?

[mustang656man]

i asked before about your clutch linkage under the dash-have u checked for play there-u seem to have skipped over my question! wes

[Karl71]

sorry, yes we checked the linkage and not any play there.
Maybe a clue or not:
The car was entirely restored in 1997, a 43000$ restoration...all was new or rebuilt. Since then, the car has been driven a very few miles and trailered to shows. When I purchased the car, it was like new in, out, under. Not any rusty part or even dirt...
The car drove ok when I purchased it with no chatter and now, 8 months later, it does chatter.