Clutch Chatter Cure...

[philipj]

Hello all,

 

I'm coming into a few situations while searching for a vehicle, and like to be better informed before I decide... Many "restored" or original examples that have not been driven for many years may suffer from something called clutch chatter?... If you try to rev the engine slightly as you release the clutch the car will shake itself apart!

 

If the clutch disk is within specs, but somehow rusted into the flywheel, can driving the car eventually be a cure? or do you have to drop the transmission (or pull the engine/whichever is easier on these cars) to cure the problem? Thank you.

[retiredmechanic74]

Is there a rear main seal leak? If it is or rust (which I think it is, or dried oil) driving it could help. You could try running the engine foot on the brake and holding the clutch pedal up enough to allow the clutch disk to rub on the flywheel and pressure plate (be careful not to overheat the clutch assm.) Do this a number of the times (each time letting the clutch cool down) or you could just take it apart and clean it.

[Mark Shaw]

What year & model is the car?

Edited January 25, 2018 by Mark Shaw (see edit history)

[Ben Bruce aka First Born]

A lot of times it is due to defective motor/transmission mounts.

 

  Ben

[Dynaflash8]

I experience this, more or less, on all of my straight 8 Buicks which don't get run a lot.  They all chatter and they do improve somewhat with use until they sit again for 6 or 8 weeks.  The Series 40-50 were noted for chatter, but Buick stuck with the waffle clutch disc from 1939 through 1955.  However, in 1942 they did increase the size of the clutch disc and pressure plate facing.  Both of my Roadmasters I've owned in the last 10-minus years have this problem, and both cars sat around for a long time.  On the convertible sedan if I slipped the clutch a little when first starting out, it would get decent for the rest of the day.  On the current car in which I just had apart to reseal the torque ball, it will do it on any start with engine revs up.  If I pop the clutch I have to be careful it doesn't leap frog.  If I ease the clutch out it chatters a lot.  If I ease the clutch out and start off slowly did doesn't chatter.  I may just learn this car and drive it accordingly.  Nevertheless I'm looking for a rebuilt clutch pressure plate and disc, or the unlikely find of NOS.  Short of that, I'm looking for a used pressure plate and disc that I can send off to have rebuilt.  I'm not in a position to get the car torn down and send off the current unit to Indiana or someplace to have it rebuilt.  That said, I guess I'm in the market for something now and I'll drive it as is until then.

[Dynaflash8]

6 minutes ago, Ben Bruce aka First Born said:

A lot of times it is due to defective motor/transmission mounts.

 

  Ben

Yes, that is true  too, but the mechanic who installed the new torque ball seal told me all the mounts are good.  I have them, new/nos both so maybe I should just put them in on general principles, what do you think?

[Ben Bruce aka First Born]

Well, will not hurt, except for the work involved.  Is the Roadmaster clutch different size than the small series?  I was able to install a clutch/pressure plate set from 1995 Jeep Cherokee into mine.  I bet there is one out there that will fit the big series. 

 

  Ben

[philipj]

Again, not a straightforward solution, since there are other things to consider such as engine and transmission mounts apparently.. The vehicle I am looking at is a 38 Special with about 33K (though I fear it may have gone around once) It seems that the only right way about it is a modern (10.5") clutch disk and new pressure plate?

I always find there are no shortcuts to these problems, but thought I check...

[Ben Bruce aka First Born]

philipj,  have you driven the car and it does in fact chatter?  Or concerned because of what you have read?

 

  Ben

[avgwarhawk]

I experience the chatter with my 54 3 speed. Only chattered in 1st.   There was a very bad leak at the front input shaft.   The clutch was covered with gear oil.  I pulled it down.  Replaced the clutch assembly and associated throwout/pilot bearing.  Resurfaced the flywheel.   Fixed the leaking input shaft with a donut type gasket.  Reassembled.   Chatter much less but it was till present.   Motor mounts are fine.  Thrust pad was changed out.   It not as bad as it was and does not really affect the driving of the Buick.  However, still annoying   First gear is so low I'm out of in it 5 seconds.   Reading the manual it states it is ok to start in second gear on level ground as there is minimal friction heat created.    That is exactly what I do.   Start in second.   Never an issue.   I use first gear on hills and pulling stumps.  Both of these are about non-existent.   I have read that sometimes the chatter is inherent.        

[avgwarhawk]

33 minutes ago, philipj said:

Again, not a straightforward solution, since there are other things to consider such as engine and transmission mounts apparently.. The vehicle I am looking at is a 38 Special with about 33K (though I fear it may have gone around once) It seems that the only right way about it is a modern (10.5") clutch disk and new pressure plate?

I always find there are no shortcuts to these problems, but thought I check...

 

 

I installed a modern (Jeep) clutch and pressure plate.  Worked and fits well.   However, chatter was less but still present.   

[Brian_Heil]

2 hours ago, Mark Shaw said:

What year & model is the car?

 

Agree with Mark.  Different clutch designs over the years with different root causes but they all chatter.  Cone, 20s multi-disc (early and late), more modern (that are similar to today's).

[Dynaflash8]

2 hours ago, Ben Bruce aka First Born said:

Well, will not hurt, except for the work involved.  Is the Roadmaster clutch different size than the small series?  I was able to install a clutch/pressure plate set from 1995 Jeep Cherokee into mine.  I bet there is one out there that will fit the big series. 

 

  Ben

Yes, it is 10.5 inches diameter, and the supplier tells me some were 11 inches, while the small cars had a 10-inch diameter.  All of this conversation today has cost me a bundle    I got to thinking about it and looked in Bob's catalog where he listed the complete rebuilt pressure plate.  I called, and he only had one.  Well, you know what happened then, I immediately bought it whether I needed it or not.  Well, that let to the clutch disc (I found I had a core in the garage from a '39 Century 66S I had at least 20 years ago) and I bought that too.  Figured I might as well buy the throwout bearing too (you know how it is) and the retainer spring too (there might be one of those in my bins....they were available from Buick at least into the 1990's).  Well, you know how it is when you get to thinking.  "Better be safe than sorry, besides it's only money, " you say to yourself.  It cost me $13.65 to send him the old clutch disc in order to get the $65 core charge back.  Since I didn't have a pressure plate core, that was another $100.  To top all of this day off, I drove my Roadmaster to the auto paint store to get a picture taken of the color ---black you understand.  Well the paint shop said, "almost all blacks are different from each other," didn't they?  You'll be interested to know that oldtime Buick Carlsbad black laquer (Duco) matches a modern BMW black and apparently none other.  To top the day off, the Buick chattered like the dickens leaving home like the Sallion he is, but by the time I got back home she was as smooth as a Mare or a pussy cat.  That always happens when you buy something you really have to have, right? 

[Matt Harwood]

It's been my experience in many cases that clutch chatter is very much like "warped" brake rotors. That is, there are deposits on the flywheel (or rotor) that cause uneven friction across the face and hence the chatter (or brake shudder). The flywheel or brake rotors aren't actually warped (which seems ridiculous on the face). I often cure my brake warpage by pulling off the wheel and hitting the brake disc surfaces with a fine sanding disc on my die-grinder to kind of scuff the surface clean and get the deposits off. Earl describing that he heats up the clutch and it goes away is largely doing the same thing.

 

It's not always the cause, of course, but in many cases when I've gone after a chattering clutch, there has been no visible culprit except deposits on the flywheel that you can often feel with your fingers. Of course, once you're in that far, you may as well surface the flywheel and replace the disc at least, so it's academic. But it's always worth trying to get the clutch heated up to see if it improves. You won't hurt it if you get it warm enough to start to smell it--just don't do it every day.

[RiKi5156B]

I had read years ago that farmers would get chatter leading to slippage because of a rear main leak. The down home fix for this was to take off an inspection plate on the top of the bellhousing,(Chevy or dodge don’t remember) then ease the front bumper up to a tree and let the clutch out in low. The clutch would slip while farmer joe poured kerosene or enamel reducer into the inspection access. When the engine stalled it was clean and good to go. For a while.

[Dynaflash8]

2 hours ago, Matt Harwood said:

It's been my experience in many cases that clutch chatter is very much like "warped" brake rotors. That is, there are deposits on the flywheel (or rotor) that cause uneven friction across the face and hence the chatter (or brake shudder). The flywheel or brake rotors aren't actually warped (which seems ridiculous on the face). I often cure my brake warpage by pulling off the wheel and hitting the brake disc surfaces with a fine sanding disc on my die-grinder to kind of scuff the surface clean and get the deposits off. Earl describing that he heats up the clutch and it goes away is largely doing the same thing.

 

It's not always the cause, of course, but in many cases when I've gone after a chattering clutch, there has been no visible culprit except deposits on the flywheel that you can often feel with your fingers. Of course, once you're in that far, you may as well surface the flywheel and replace the disc at least, so it's academic. But it's always worth trying to get the clutch heated up to see if it improves. You won't hurt it if you get it warm enough to start to smell it--just don't do it every day.

Thanks Matt.  All that clutch stuff cost me $584, which kind of shocked me once it added up.  I hope I never actually need to use it.  I'm sure my mechanic hopes so more.

[SteveBigD4]

I have had my 1938 Special for 40 years and when I got it it had serious oil leaks that caused very bad clutch chatter. After rebuilding the engine to eliminate the oil leaks I replaced all the clutch elements, turned the flywheel, rebuilt the trani and checked the bell housing alignment and adjusted the rear engine mount shims.  I also replaced all the engine mounts and the central trani mount.  Now I still have some clutch chatter but not nearly as bad as before.  I found as others have said that slipping the clutch in 2nd with the brake applied for a few seconds virtually eliminates the chatter until the next time I drive it. 

 

It appears to be a part of the nature of these cars but also as Matt said could be due to deposits on the flywheel. For brake shudder I bed the brakes by making a few repetitive hard stops from 60MPH or so followed by some cool down cruising.  This eliminates the shudder by seating the pads and burning off the deposits.  I think that slipping the clutch to heat it up does a similar thing for the flywheel.

Steve D

[MCHinson]

I guess I have been lucky. I have only had my 1937 Century for about 4 years but I have never experienced this problem. I have only driven the 1938 project a short amount back and forth in the driveway and did not notice it on it either. I hope it is in as good a condition as the 1937.

[Spinneyhill]

Way back, my first car was a Morris 1100. The clutch chattered. I was told it was oil on the clutch. So I opened the inspection hatch on the top, started the engine and poured petrol (I think) over the clutch. It washed off whatever was causing the problem. No more chatter. Looking back, how crazy is that?

[Thriller]

My '41 chatters in 1st only. 

 

[avgwarhawk]

1 minute ago, Thriller said:

My '41 chatters in 1st only. 

 

Thats my experience in my 54.  Sometimes I think the gear is so low the clutch can't keep up. 

[Dynaflash8]

3 minutes ago, Thriller said:

My '41 chatters in 1st only. 

 

Mine too.  The '39 Special's do the same.

[Dynaflash8]

7 hours ago, kgreen said:

Earl:  I've inquired at a couple shops that specialize in clutch and pressure plate services and found the cost to be about $450.  This cost includes rebuilt and balanced pressure plate with new springs and clutch plate as required, new clutch, pilot bearing and throw out bearing plus clutch alignment tool.  I'm getting mine done in Atlanta at:  http://www.clutchspecialty.com/products.html   I've also contacted these guys: http://www.clutchdynamicsinc.com/domestic-clutch-kits

 

In both cases they report that they supply a 10.5 inch clutch plate.  There were two pressure plates for 1940, the waffle shaped spring for the 40 and 50 series cars and a three pronged spring actuator for the rest of the series with the big engines.  

 

As an aside, I've also learned that the Atlanta Clutch guys will reline my brake shoes.  I'm headed down today with the pressure plate and want to learn what brake lining material they use.

Ken, I didn't want to have my car down while waiting for a clutch pressure plate and disc.  To do what you did, I'd have had to send the pressure plate from my car, and that wasn't convenient for a running, driving car.  However, now you remind me about balancing.  I could be interested in sending my new rebuild pressure plate from Bob's off to your place in Atlanta to be balanced.  I'll have to call Bob's and ask him about the balancing.  Regarding balancing I'd be more worried about vibration.  After an engine rebuild and new clutch in the blue '39 Special I had a vibration at around 52 mph for years.  Once that clutch and the next one wore out the vibration went away.

[Lawrence Helfand]

Hello All, So much chatter! Over the years I have experienced chatter in all sorts of manual clutch 2 , 4 and 6 wheeled vehicles of various makes and I mention this to say it is not a Buick design flaw even if every old Buick you might own does this. Every prewar flathead Ford I owned chattered in reverse only but I cant say it was inherent to Fords. Takes very little contamination of the clutch surfaces to accomplish that as Matt Harwood stated. I find in most vintage cars and bikes with a dry clutch like Moto Guzzi and BMW storage often compromises the rear seal of both engine and transmission and sometimes as several have mentioned you can burn it off with use or abuse but if that dried up seal is still weeping it wont improve and old oil soaked into the clutch can glaze unevenly. They used to sell universal anti clutch chatter devices but I do not think these would ever do much. 

My 1941 Century 66S chattered so bad after its 45 year storage I had to avoid all possible lights I might get caught at with incline starts as getting away was blurring my vision and I could not burn it off or improve it with use.  I had my original clutch assembly rebuilt at a shop where after truing the pressure plate face and renewing clutch material and release arm pins etc it was then spun assembled for balancing. I also renewed seals of course and torque ball seal for which I prefer the original cork material over the rubber as the cork will swell and seal better with less leakage having used both now. 

I highly recommend the shop I choose, sourced from an advert they ran on the Long Island Buick Club website. They specialize in vintage clutch assembly's and I think you are always better off renewing original parts  over reproduction if still serviceable. The shop is called Falcon Clutch and they are in Deer Park Long Island NY and have a website. The shop is organised and tidy with all the special equipment needed to rebuild your old clutch and their experience with vintage is a plus. Best of all the price is very friendly. I now have the smoothest sweetest clutch and the second gear start which I could never do is like butter and finally I understand why Buick recommended this for mostly level starts. I spent half of what replacing everything with new parts costs and retain the parts she rolled off the line with in 41 which were quite well made. Ever notice how many truly awful looking Buick barn and field cars you see for sale that say it runs or motor turns over. So rarely do I see motor stuck! Try that with any other make. Love my Buick even more now! 

[avgwarhawk]

This is why I second gear start almost all the time. It's never a problem or chatter.  Besides, I get to third much faster. It's the gear I enjoy the most cause I'm done rowing and cruising. That is the sweet spot.  

[philipj]

I talked to an older gentleman from PA who has worked on these cars all his life.. He mentioned that clutch clatter is caused by the pressure plate stiffening from rust, dirt and oil over time... On cars that have sat for a while and have this issue, he mentioned that while the engine is running and with the bottom inspection cover removed from the bellhousing, use a light lubricant or penetrating oil and spray the pressure plate liberally. Makes quite a mess, but does takes care of the problem... 

[JFranklin]

I would only spray lubricant on clutch surfaces as a last resort before a total replacement!!! Maybe brakleen if anything before that.

Edited January 28, 2018 by JFranklin
Added thought (see edit history)

[raydurr]

I know I am about to get lambasted for what my grandfather told me fixed clutch grabbing on 1929 Buick cars. He owned several Buicks from 1927 thru early 30s. 1929s were his favorite for his rural delivery routes on unpaved roads in East Texas. I think he owned up to five 1929s over the years. He swore this took the grab out of  clutch release and engagement. He would block the bell housing drain slot with cloth or paper. He would remove the clutch inspection handhole from the upper bell housing. He would fill the flywheel housing with "coal oil" or kerosene for a few minutes. He would work the clutch pedal maybe even starting the engine. He would then drain the fluid from the housing. He said clutch would feel funny at engagement for a period but it always stopped the chatter. My 1929 Buick clutch chatters but not unbearable.

[Bloo]

As I recall, (and I dont have it handy to look), the 1937 Buick shop manual has a procedure for setting up the "fingers" on the pressure plate, and it is a critical adjustment for smooth operation.

 

As others have pointed out, the common causes of clutch chatter are:

 

Transmission input shaft not concentric with crankshaft. This is checked with a dial indicator with the transmission out.

Pilot bushing or bearing bad, allowing the disc to clamp down not quite centered.

Bad motor mounts allowing movement that causes an engage-disengage-engage motion in the clutch linkage.

Contamination of the clutch disc lining with oil

Pressure plate not contacting the disc evenly on release (I think the shop manual will have some insight and a bench procedure)

 

It may also be that it is not perfect and your driving technique may have to be adjusted. A crankshaft is speeding up and slowing down  again every time a plug fires. The drive shaft will insist on turning at a constant speed. When you join the two, there is a rocking-back-and-forth motion. On a low first gear, on takeoff, the motion can be very hard to control. Springs in the clutch disc hub are meant to take up this motion while underway.