Touching clutch and pp surfaces

[Russell Reay]

Last winter I converted to a T5, and used a new Burtz lightened flywheel, new 9" clutch disc and Early V8 pressure plate. Everything went together fine, just as I expected, but I made no effort to avoid handling the components. I just saw Paul Shinn's latest video on clutch replacement, and he carefully avoided touching the clutch and pp surfaces. My clutch chatters terribly upon take off, but is smooth going thru the gears, and there is no slippage. I have assumed that the flywheel-clutch-pp surfaces are not in perfect alignment. Is it possible that oils from handling are more likely the cause? A tear-down will be necessary, but I would like to be aware of likely problems.

[J Franklin]

You might try some Brakekleen on the clutch through the inspection plate access and see what it does. I was always taught not to handle those surfaces or clean before use.

[JayJay]

I do an acetone or brake cleaner scrub on all surfaces (flywheel, disc x 2 sides, pressure plate) just before assembly. Scrub and rinse until your rag comes back clean.

[nkaminar]

The other thing to do, of course, is to wear those rubber mechanic's gloves when assembling the clutch.

[P.S.]

So, a Paul Shinn video taught you something? That's what they're for. Mission accomplished.

[BRENT in 10-uh-C]

Sponsored Links (Register now to hide all advertisements)

Well, not to diminish Paul's teachings but IMO, while it never hurts to be that cautious, it honestly affects nothing getting fingerprint oils or body salts onto the flywheel or Pressure Plates surfaces. Let's think in this light...



To begin with, oil rarely causes the Clutch to to chatter. It can cause it to slip however, -but then as soon as the surface oils have been overcome by friction (-i.e. heat), the issue is gone. This would be the case with body oils, etc.

So what causes 'clutch chatter'? As mentioned, it can be an alignment issue however generally speaking, the gyro effect of a rotating mass always seeks a centerline which masks the alignment issue. So in other words, the chatter is usually light & subsides quickly.

The biggest cause of chatter in a Model-A driveline from my experiences is due to a worn Clutch Pilot Bearing, or a worn end of the Main Drive Gear (-a/k/a Input Shaft) where it enters the Pilot Bearing, or a worn Main Shaft Bearing. Any one of these (-or combination of the 3) allows the Clutch Disc to be outside of the Pressure Plate centerline. When the Clutch is engaged, it is trying to seek a centerline, and therefore causes chatter until it becomes centered with the P/P. It was mentioned that the chattering does not happen once at operating speeds and during shifting, ...which this is because the Main Drive Gear (-Input Shaft) is already rotating within the centerline and the gyroing effect basically maintains that centerline of the input shaft and clutch disc even when the pressure of the Pressure Plate has been momentarily released.

[Russell Reay]

Originally Posted by BRENT in 10-uh-C

So what causes 'clutch chatter'? As mentioned, it can be an alignment issue however generally speaking, the gyro effect of a rotating mass always seeks a centerline which masks the alignment issue. So in other words, the chatter is usually light & subsides quickly.

The biggest cause of chatter in a Model-A driveline from my experiences is due to a worn Clutch Pilot Bearing, or a worn end of the Main Drive Gear (-a/k/a Input Shaft) where it enters the Pilot Bearing, or a worn Main Shaft Bearing. Any one of these (-or combination of the 3) allows the Clutch Disc to be outside of the Pressure Plate centerline. When the Clutch is engaged, it is trying to seek a centerline, and therefore causes chatter until it becomes centered with the P/P. It was mentioned that the chattering does not happen once at operating speeds and during shifting, ...which this is because the Main Drive Gear (-Input Shaft) is already rotating within the centerline and the gyroing effect basically maintains that centerline of the input shaft and clutch disc even when the pressure of the Pressure Plate has been momentarily released.

I am also skeptical of the significance of body oils, but I don't have the experience or credentials to argue the point. The pilot bearing is new as is the throwout bearing. When installing the flywheel and AA flywheel housing I recall checking everything with a dial indicator, but I foolishly did not record the results. I do remember that there was a little variation, but decided at the time they were not significant. After teardown and re-examination I may find my chatter source.

[Terry Burtz, Calif]

Does your disc match the T5 input shaft, or was the T5 input shaft modified to use a Model A disc?

[P.S.]

Originally Posted by BRENT in 10-uh-C

Well, not to diminish Paul's teachings but IMO, while it never hurts to be that cautious, it honestly affects nothing getting fingerprint oils or body salts onto the flywheel or Pressure Plates surfaces. Let's think in this light...

My 95 year old dad disagrees. I just follow directions, so keep my greasy hands off the friction surfaces, as told by the old guy who knows way more than me.

My high school shop teacher said the same thing and did a demo one time. The same thing you describe about overcoming the lubricant and the surfaces eventually grabbing is what lead to a chattering clutch in our shop experiment. Where the friction plate and disc grabbed, a slight ridge could be seen. Do that over and over, and you get an uneven surface. That experiment stands out in my mind, so I do as dad says and keep my greasy paws off the clutch disc, flywheel, and pressure plate. Just a habit now. None of my cars have a chattering clutch.

Maybe that's why, or maybe not. I mean, it can't hurt.

[Russell Reay]

Originally Posted by Terry Burtz, Calif

Does your disc match the T5 input shaft, or was the T5 input shaft modified to use a Model A disc?

The clutch disc is for the T5 input shaft. Disc supplied by Vintage Metalworks, pressure plate and TO bearing from Early Ford V8 sales

[Marshall V. Daut]

There were clutch disk plates available during and since the Model A era that had no springs in the hubs to ease take-offs when the clutch pedal was let out. They are the so-called "Heavy Duty Truck" disks that were designed to handle heavier vehicles, such as AA trucks, whose drivers could have cared less about clutch chatter. It wasn't THEIR truck after all, rather the company's. They lasted forever, but made life miserable in a passenger car. These disks will almost always cause clutch chatter upon engaging the clutch. Over the years they have been sold by unscrupulous parts vendors to unsuspecting buyers at cheaper prices than the quality disks with CAGED springs. So, Model A people being the second-most parsimonious car owners on this planet (not far behind Model T owners), opted for the cheaper disk. These disks are still out there by the thousands. (Thanks, Rick's Antique Auto and J.C. Whitney!!!, et al.) Of the Model A clutch chattering problems I have fixed in the last 60 years, probably 90% were caused by this ^%#(& clutch disk. At one time I had a cardboard box full of 'em I had replaced before I finally threw them away to save future Model A owners the misery they caused. The remaining 10% chattering problems I experienced concerned disks, whose springs had fallen out of their bores or by badly scored/burned flywheel and/or pressure plate face surfaces. Not one was caused by the presence of grease or oil, which although were often present from over-lubing the throwout bearing, a failed throwout bearing, a failed pilot bearing or a leaking rear main engine bearing, only caused clutch slippage, not chattering. Others have apparently experienced chatter from oil or grease, but I haven't.
You can check which clutch disk you have by taking off the clutch inspection plate on the top of the bellhousing and looking at the disk's hub. If there are no springs present, that's why the clutch chatters. Not a fun job correcting this problem, but installing the correct disk WILL make life enjoyable again without that horrible and embarrassing clutch chattering.
Marshall

[1crosscut]

A few years ago a fellow club member was having trouble with chatter after installing a new clutch.
The flywheel was surfaced along with the pressure plate assembly being rebuilt and surfaced. It also had a new one of the good clutch disks with the caged springs.
The engine and clutch was out of the car for the third time before discovering that the cause of the chatter was a slightly raised area (bump) about the size of a nickel on one side of the clutch disc.
Just something to check.

[BRENT in 10-uh-C]

Originally Posted by P.S.

My 95 year old dad disagrees. I just follow directions, so keep my greasy hands off the friction surfaces, as told by the old guy who knows way more than me.

My high school shop teacher said the same thing and did a demo one time. The same thing you describe about overcoming the lubricant and the surfaces eventually grabbing is what lead to a chattering clutch in our shop experiment. Where the friction plate and disc grabbed, a slight ridge could be seen. Do that over and over, and you get an uneven surface. That experiment stands out in my mind, so I do as dad says and keep my greasy paws off the clutch disc, flywheel, and pressure plate. Just a habit now. None of my cars have a chattering clutch.

Maybe that's why, or maybe not. I mean, it can't hurt.

Well, we're not going to go against your Pop or the H/S Teacher, -are we??

[P.S.]

Originally Posted by BRENT in 10-uh-C

Well, we're not going to go against your Pop or the H/S Teacher, -are we??

Ah, so you've met my dad. Mules go to him for lessons on how to be stubborn.

[Hitman]

If you have body or finger oils that can affect a clutch or even braking surface. You have bigger health issues.

Old wives tails are just that. You’ll burn off any residual finger related grease by the time you reach the stop sign.

[P.S.]

The full video was published this morning- https://www.youtube.com/watch?v=BsyCPauO4P0

[Phil Brown]

What about the guy that put's all of those brand new clutch disk's in there boxes ?
Ya think that he keeps his fingers off of the contact surfaces ? and if he does touch the contact surface what happens then ? The disk get thrown out, not likley

[P.S.]

Originally Posted by Phil Brown

What about the guy that put's all of those brand new clutch disk's in there boxes ?
Ya think that he keeps his fingers off of the contact surfaces ? and if he does touch the contact surface what happens then ? The disk get thrown out, not likley

The discs are in plastic bags before he gets his grimy hands on them and puts them in boxes.

Clutch discs are somewhat smooth and would show fingerprints. The painted metal parts would certainly show fingerprints. Yet, you open a brand new clutch disc package and there are no fingerprints on them.

My guess is assemblers wear gloves.

[katy]

Deleted, dumb question