Clutch Chatter

[Bill Pritchard]

I recently bought a 69 Chevelle SS396 with M20 4 speed and it has clutch chatter when slowly engaging the clutch, either when just starting out from a stop or when downshifting. I bought the car knowing that it had a problem in this regard, so it was not a surprise to me....I just want to get the problem fixed.

The car has all new (remanufactured) clutch disc and pressure plate, new throwout bearing and pilot bushing, and the flywheel was resurfaced. The M20 was completely gone through by Crash. It was initially assembled with all these new components and this shuddering problem came to light. Everything was removed, inspected, cleaned with lacquer thinner to ensure absolute cleanliness, and reassembled. The problem still was there. I have removed everything again and am looking for the root cause. Have a look at these pics of my clutch fork with throwout bearing installed on it. The spring steel 'tangs' that hold tension on it are not well centered on the face of the throwout bearing collar. On the one side, the tang is barely making contact with the edge of the bearing collar. Does anyone think this could be the cause of the shuddering? I examined all other components and could find nothing else that looked suspect. With the bearing removed from the clutch fork, the tangs do not appear terribly offset in the opening on the fork.

Before I tore this all apart, I tried jacking up each side of the engine to see if the motor mounts might be broken, as I know that could also cause shuddering....they appeared to me to be solidly attached.

Since I have everything apart, I do plan to install another clutch kit using new, non-remanufactured components. I will be interested to see if another throwout bearing has the same offset appearance as this one does. If so, I will probably try another clutch fork.

Any help would be greatly appreciated!!

http://i70.photobucket.com/albums/i115/bpritchard/100_2442_zpsen0vytap.jpg (http://s70.photobucket.com/user/bpritchard/media/100_2442_zpsen0vytap.jpg.html)

http://i70.photobucket.com/albums/i115/bpritchard/100_2440_zpsdsfcifmq.jpg (http://s70.photobucket.com/user/bpritchard/media/100_2440_zpsdsfcifmq.jpg.html)

http://i70.photobucket.com/albums/i115/bpritchard/100_2444_zpskpy2lwdx.jpg (http://s70.photobucket.com/user/bpritchard/media/100_2444_zpskpy2lwdx.jpg.html)

[Postsedan]

Bill,

I sent you an email.....easy fix.

Dan

[SS427]

Very easy to fix and common mistake.

[William]

This is a common problem with '69 Camaros when <span style="font-style: italic">incorrect</span> motor mounts are used; maybe Chevelles are the same. I know you checked the mounts but they could still be wrong for the application.

For '69 they switched to the interlocking motor mount design for 302/350/BB engines. The new mount was narrower and thicker than the 67-68 so the frame bracket was re-designed. The listing in some Mc Parts books is either incorrect or confusing and they give you 67-68 motor mounts even if you request '69s. They will fit on the '69 frame bracket but it is a sloppy fit allowing the engine to move fore/aft. The 67-68 mount is thinner so the engine isn't positioned correctly. It's not easy to tell but the correct 69 mount is a tight fit on the bracket; the 67-68 mount will have a noticeable gap on one or both sides. I believe the 67-68 mount is 2-1/2&quot; wide the 69 is 2-1/4&quot;. Height difference was about 3/8&quot;.

[Billohio]

I am getting closer to installing my engine and transmission. What is wrong here? I am sure I will do it!! I am taking out my original motor mounts and putting in a new set.

[earntaz]

Bill -- The two clips on each side should be in the groove of the throwout bearing ... not behind it. Also, make sure the disc, PP and flywheel are absolutely free of any contamination -- especially oil and dirt off your hands.

[Verne_Frantz]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: earntaz</div><div class="ubbcode-body">Bill -- The two clips on each side should be in the groove of the throwout bearing ... not behind it. Also, make sure the disc, PP and flywheel are absolutely free of any contamination -- especially oil and dirt off your hands. </div></div>

Exactly. The bearing is installed incorrectly on the fork.

Verne <<GRAEMLIN_URL>>/biggthumpup.gif

[dale68z]

^^^^ correct

The TO bearing pivots on the tangs of the clip, keeping the TO bearing square to the pressure plate as the fork moves.

[Billohio]

OK I had good instructions and remember that. Thanks guys

[earntaz]

Also -- there was reference made to cleaning all the surfaces, meaning disc, PP and flywheel. I've seen people use aerosol carbuator cleaner -- NOT!! ... most carb cleaner contains a small amount of lubricant for throttle shafts, etc. If anything -- use brake clean as it normally doesn't leave a residue.

[markjohnson]

Is that one of those plastic throwout bearings?

[Bill Pritchard]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: markjohnson</div><div class="ubbcode-body">Is that one of those plastic throwout bearings? </div></div>

The center collar portion is definitely some type of non-ferrous material, possibly some type of plastic. The actual bearing portion is steel.

So this is the proper way for the bearing to be installed?

http://i70.photobucket.com/albums/i115/bpritchard/100_2445_zpsauy3q9nb.jpg (http://s70.photobucket.com/user/bpritchard/media/100_2445_zpsauy3q9nb.jpg.html)

To be perfectly honest, it may have been that way when it was in the car.....in the pictures I posted yesterday, I may have reinstalled it with the tangs on the outside of the collar. It has been over 30 years since I have installed a throwout bearing on a GM product, so I really don't remember how I used to do it.

One other thing I noticed today, the collar portion is not perfectly concentric with the bearing portion...

http://i70.photobucket.com/albums/i115/bpritchard/100_2447_zpsyh4vsem8.jpg (http://s70.photobucket.com/user/bpritchard/media/100_2447_zpsyh4vsem8.jpg.html)

http://i70.photobucket.com/albums/i115/bpritchard/100_2446_zpst3mpdpox.jpg (http://s70.photobucket.com/user/bpritchard/media/100_2446_zpst3mpdpox.jpg.html)

And finally, to address William's post about the motor mounts....for at least 6 years prior to last October, this car had a different clutch and transmission in it - with the same motor mounts that are in it now - and there was no chattering at that time. It was an excellent and interesting point to bring up, but I think it does not apply to this car.

Thanks so much for all replies thus far!

[earntaz]

The fork is now installed on the bearing correctly ... does the bearing turn freely? Seems to be a lot of scoring on the bearing surface or in just might be the picture. IMHO -- see if you can locate a throwout bearing that is all metal ...

[Postsedan]

Yep...ditto....I would get an all metal Throwout Bearing.

Dan

[markjohnson]

Gotta agree about an all metal bearing with a light coating of Anti-Seize on the input shaft bearing snout. TO bearings are cheap but are a laborious job to change if they need it. It's also a VERY good idea to adjust the clutch linkage exactly to the Assembly or Service Manual. I've never understood why so many people just kind of guess at it! As clutch wear occurs, the diaphragm fingers extend towards the rear of the car and put them into full-time contact with the TO bearing face.

[SS427]

We recently had a car in the shop getting quite a makeover and this car also had clutch chatter. Upon disassembly we found the the previous mechanic installed the starter wiring harness bellhousing clip in BETWEEN the bellhousing and engine flange not behind the bellhousing bolt as was intended. This bound the transmission input shaft and scored the pilot bushing. The other symptom was that it kept locking up between shifts. Check everything.

[Bill Pritchard]

Yes, the bearing spins and pivots freely mounted as shown in that last picture. I will be ordering a whole new clutch kit (probably a Hays since that seems to be Dan's favorite <<GRAEMLIN_URL>>/grin.gif ) and hopefully that will have an all metal bearing. I have anti-seize for the input shaft bearing snout. Thankfully both the starter wiring harness clip and the speedo cable clip were properly mounted directly under their respective bolt heads.

Thanks again, gents <<GRAEMLIN_URL>>/worship.gif

[earntaz]

Maybe your jobber who is supplying the Hays clutch assembly will include the correct throwout bearing. In many cases, a diaphragm clutch and three finger clutch will require a matching throwout bearing...TAZ

[Bill Pritchard]

Yes, the clutch kit includes a new bearing.

[Bill Pritchard]

The new Hays clutch kit arrived yesterday, and the throwout bearing is all metal <<GRAEMLIN_URL>>/biggthumpup.gif

[mockingbird812]

Good to hear Bill. Man - look at all the USEFUL help you got here. THAT is what I'm talkin' about!!!!!!!!!!! <<GRAEMLIN_URL>>/3gears.gif


Bet you can't wait to hit the road with this bad boy, huh Bill?!!! <<GRAEMLIN_URL>>/grin.gif

[PeteLeathersac]

As Rick mentioned, check Pilot bearing/bushing when trans out also best check trans front bearing play too.
Does a new Pilot come w/ the kit?
<<GRAEMLIN_URL>>/beers.gif
~ Pete

[earntaz]

As Rick mentioned, check Pilot bearing/bushing when trans out also best check trans front bearing play too.

X3

[Rixls6]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: PeteLeathersac</div><div class="ubbcode-body">
As Rick mentioned, check Pilot bearing/bushing when trans out also best check trans front bearing play too.
Does a new Pilot come w/ the kit?
<<GRAEMLIN_URL>>/beers.gif
~ Pete </div></div>

The car had a brand new pilot bushing, and the trans was a fresh rebuild by Crash.
Regardless, I would replace the pilot bushing again while it's opened up to get at.

[Xplantdad]

Bill, get 'er going...so you can bring it out to Pavilions on Saturday <<GRAEMLIN_URL>>/smile.gif

[SS427]

An easy way to get the bushing out, insert grease behind the bushing and a little around an old input shaft on the bearing surface if you have one. Insert the shaft all the way in and using a rubber mallet, hit it a few times and the hydraulics will push the bushing right out. Works great.

[SuperNovaSS]

Wax also works well. Also, make sure the pilot bushing is actually brass and not brass colored/plated steel.

Jason

[Verne_Frantz]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SuperNovaSS</div><div class="ubbcode-body">Wax also works well. Also, make sure the pilot bushing is actually brass and not brass colored/plated steel.

Jason </div></div>

Negative, Make sure it's an Oilite bushing. And do NOT grease it other than a <span style="text-decoration: underline">very</span> light coat on the input shaft. Too much grease will fill up the pores in the bushing and prevent the oil from doing it's job.

Verne <<GRAEMLIN_URL>>/flag.gif

If it doesn't say Oilite on the packaging you can leave it sit on a paper towel for a while and look for a dark ring where the oil wicked out.

[luzl78]

Verne, is it ok to use old nos Gm bushings or oillite? Do you have the part number for the oillite bushing for gm 65-72? Thanks. Jeff

[Bill Pritchard]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SS427</div><div class="ubbcode-body">An easy way to get the bushing out, insert grease behind the bushing and a little around an old input shaft on the bearing surface if you have one. Insert the shaft all the way in and using a rubber mallet, hit it a few times and the hydraulics will push the bushing right out. Works great. </div></div>

Outstanding idea, Rick, thank you very much. I do indeed have an old Muncie input shaft that I have had laying around for 30 years or more, and I finally get to put it to good use! I was planning to use it for the clutch installation anyway.

As Rick P. says, he installed a new pilot bushing when he replaced the clutch last fall, and it doesn't have 30 miles on it, so I seriously doubt that there are any issues with it.....but they are so cheap and relatively easy to replace that I think I would be foolish to NOT do so.


Thanks again for all the helpful advice here, guys.....as Sam indicates, this place rocks!!! <<GRAEMLIN_URL>>/youguysrock.gif

[Bill Pritchard]

Since that sounded like such a slick idea, I had to go right out to the garage and try it....and it worked perfectly. Thanks again Rick Nelson!

[Verne_Frantz]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: luzl78</div><div class="ubbcode-body">Verne, is it ok to use old nos Gm bushings or oillite? Do you have the part number for the oillite bushing for gm 65-72? Thanks. Jeff </div></div>

The GM bushings <span style="text-decoration: underline">were</span> Oilite. Several suppliers have them. I'd try NAPA first.

Verne <<GRAEMLIN_URL>>/biggthumpup.gif

[Bill Pritchard]

I would assume that the bushing I just removed from the car (the one that Rick P. put in it last fall) was from NAPA, since that's where he bought the clutch. I don't know whether or not it is an Oilite bushing, but a magnet definitely does stick to it <<GRAEMLIN_URL>>/dunno.gif

I just ordered a new pilot bushing from RockAuto.com so will see what that is like.

http://www.rockauto.com/catalog/moreinfo.php?pk=221649&amp;cc=1038877&amp;jnid=480&amp;jpid=2

[markjohnson]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bill Pritchard</div><div class="ubbcode-body">I would assume that the bushing I just removed from the car (the one that Rick P. put in it last fall) was from NAPA, since that's where he bought the clutch. I don't know whether or not it is an Oilite bushing, but a magnet definitely does stick to it <<GRAEMLIN_URL>>/dunno.gif

I just ordered a new pilot bushing from RockAuto.com so will see what that is like.

http://www.rockauto.com/catalog/moreinfo.php?pk=221649&amp;cc=1038877&amp;jnid=480&amp;jpid=2 </div></div>

Wash &amp; dry it thoroughly then hold a cigarette lighter or lit match up to it. If it sweats oil, it's an Oilite.

[luzl78]

I think the new bushings are bronze coated steel.

[Bill Pritchard]

New pilot bushing from Rock Auto arrived today. It is a National Bearings/Federal Mogul item, made in USA, magnet definitely does NOT stick to it. I am leaving it sit on a paper towel to see what happens, but my guess is that it is NOT oil impregnated.

[earntaz]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SS427</div><div class="ubbcode-body">An easy way to get the bushing out, insert grease behind the bushing and a little around an old input shaft on the bearing surface if you have one. Insert the shaft all the way in and using a rubber mallet, hit it a few times and the hydraulics will push the bushing right out. Works great.</div></div>

In GM tech school, there were all sorts of pullers, etc. for various tasks -- we were also instructed on this little trick. With that being said, I have NEVER used a puller on many engines -- pack the cavity with grease, tap on an old input shaft and hydraulic the bushing out.

[Bill Pritchard]

New pilot bushing sat on a paper towel overnight and left zero trace of oil or anything. I installed it and put a very light coat of anti-seize on the inside.


Progress today <<GRAEMLIN_URL>>/headbang.gif

http://i70.photobucket.com/albums/i115/bpritchard/100_2461_zpsrsmc2rej.jpg (http://s70.photobucket.com/user/bpritchard/media/100_2461_zpsrsmc2rej.jpg.html)


More progress....Thanks to several responders in this thread, note the proper positioning of the throwout bearing on the fork <<GRAEMLIN_URL>>/grin.gif Bearing came from Hays with a light coating of grease on the inside of the collar.

http://i70.photobucket.com/albums/i115/bpritchard/100_2463_zpsvplht6sr.jpg (http://s70.photobucket.com/user/bpritchard/media/100_2463_zpsvplht6sr.jpg.html)


Still more progress....

http://i70.photobucket.com/albums/i115/bpritchard/100_2464_zpshoys3ydq.jpg (http://s70.photobucket.com/user/bpritchard/media/100_2464_zpshoys3ydq.jpg.html)

[iluv69s]

not to steal the thread, but I pulled a car apart a few years back and it had a roller pilot bearing...what do u guys think of them?

[Billohio]

I used a piece of bread to push a bushing out instead of grease once. Worked great and no mess. Keep packing the bread in and forced it right out

[Verne_Frantz]

They depend on perfect alignment to have any benefit. If things don't line up within .0005 of perfect, they are a waste and could cause more problems. Think of it as though you replaced your rod bearings with needle bearings instead of sleeve bearings. Does one end of the needles have the same clearance and pressure as the other end??? Instead of riding on a bearing surface of about 3/4&quot; you might be riding on a bearing surface of .030&quot;. What makes you feel safer?

Verne

[earntaz]

If the needle bearings were the hot setup -- GM would have installed them in many more vehicles ... bronze is pretty much fool proof (well most of the time) ...

[njsteve]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bill Pritchard</div><div class="ubbcode-body">

Still more progress....

http://i70.photobucket.com/albums/i115/bpritchard/100_2464_zpshoys3ydq.jpg (http://s70.photobucket.com/user/bpritchard/media/100_2464_zpshoys3ydq.jpg.html) </div></div>

I had to laugh when I saw this photo. I can't tell you how many times as a teenager I tried the old &quot;put a baggie on the tailshaft to catch the gear lube&quot; trick...and got deluged by a waterfall of gear lube when it filled the bag to capacity and then popped it. Oh, the folly of youth.... <<GRAEMLIN_URL>>/grin.gif

[Postsedan]

Old School....Plus I would bet that Bill has a very nice garage floor at home <<GRAEMLIN_URL>>/biggthumpup.gif

Dan

[m22mike]

That baggie is to keep the scorpions out.... <<GRAEMLIN_URL>>/grin.gif

[Xplantdad]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: m22mike</div><div class="ubbcode-body">That baggie is to keep the scorpions out.... <<GRAEMLIN_URL>>/grin.gif </div></div>


Shhh Mike, you are giving away all of the secrets!

[Bill Pritchard]

The baggie deal was done out of frustration...many years ago I bought plastic 'plugs' at a parts swap meet to go in place of a driveshaft yoke. Thought I still had them....I found the larger one for the T400, but of course the one for a 4 speed is MIA <<GRAEMLIN_URL>>/mad.gif Actually that picture shows the sum total of the gear lube that came out of the trans during this whole process, because I managed to keep it either fairly level or tilting forward the entire time.

Dan, my garage floor is reasonably clean but nothing to write home about. And yes, Mike, I'll bet even the scorpions would turn away at the smell/feel of gear lube. Thankfully I haven't seen any of them in the garage for a while now.

My NOS Muncie shifter body arrived today and it is installed in the car now. Feels pretty stiff....I hope it loosens up a bit with some use, otherwise I may have to put the old one back in. I have sprayed it down good with some white lithium spray grease to see if that helps it. Hopefully tomorrow it will come down off the jack stands so I can work on clutch adjustment. I will be keeping my fingers crossed that the shuddering has been vanquished with the old clutch.