Clutch disk assy. does not disengage 100%.

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
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Re: Clutch disk assy. does not disengage 100%.

Post by bazza46 » Sat Jun 05, 2021 4:11 pm

The 27/32" measurement is only valid with the Auburn style clutch. When you achieve that distance, the release fingers are protruding exactly enough for you to get the 1/16" gap between the release bearing without having to crank the bearing way out on the input shaft tube. And it sets the clamping pressure of the clutch correctly. Fingers out too far- not enough clamping pressure. Too far in -clamping pressure high, but release bearing has to go too far forward, resulting in pedal adjustment problems.
That pressure plate you have now is probably designed for a gearbox and release bearing that is closer to the clutch, so the fingers don't have to protrude so much. Some different style clutches will work, finger distance wise, but others not so. Yours looks like the latter, from the picture. The fingers look very low in the assembly, and the only adjustment is the 3 bolts, which are nor expected to be wound out as far as you have them.
Put in an original style pressure plate and she'll be O.K.
Bazza
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Re: Clutch disk assy. does not disengage 100%.

Post by Michael O. » Sat Jun 05, 2021 6:49 pm

There is no magic to solving that problem. Simply stop using the wrong parts and wondering why they don’t work!

-Clutch rod: If it isn’t 9 1/8th to 9 3/16th, center-to-center. Buy the correct one and get on with it.

-Clutch Control Tube: If the “ears” are not welded on 180 degrees from one another. Buy the correct one and get on with it.

-Throw-out Bearing: Generally the correct dimensions but cheap ones are not properly sealed with lubricant inside them for life and will squeal and grind when they fail.

-Fork: Check the “fingers” where they ride on the TO Bearing and be sure they both fit on it CORRECTLY. Also, check where the Clutch Cable Ball fits on the Fork for wear/failure and replace if needed.

-Clutch Cable: OAL is 9 ¾”.

-Clutch: Stop using clutches from other applications. BUY ONE FOR A T84. Clutch Adjustment: “experts” love to mess with the adjustments. Then when the fingers are out of whack blame the mfger. Odds are your clutch was CORRECTLY adjusted at the factory if you bought it from a REPUTABLE dealer. If so, leave it alone!

-Disk: The REPUTABLE dealers in jeep parts sell the disk with the pressure plate and, golly, gee! You get the CORRECT one instead of saving $2.00 and buying one from Ebay.

Those who mix up incorrect parts and then butcher parts that might be correct in a failed attempt to “make it work” usually end up asking for help on the gee….Hmm, wonder why???

 
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Re: Clutch disk assy. does not disengage 100%.

Post by SierraJeep » Mon Jun 07, 2021 11:37 am

Gentlemen,

Thank you all for your help and comments.

I have one T84 clutch pressure plate on order with Ron. I'll send an update after received and installed.

Andrew
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Re: Clutch disk assy. does not disengage 100% - MORE to the Story

Post by SierraJeep » Thu Jun 10, 2021 4:12 pm

Good day Gentlemen,

I removed the pressure plate to make room for the new PP on order, and WoW! I found the disk springs are striking the large nut on the fly wheel. The nuts are hacked and the springs are worn down/flatten a bit. Disk was not installed backwards.

What am I doing wrong?
Attachments
Pressure Plate.jpg
Disk.jpg
Fly wheel.jpg
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Re: Clutch disk assy. does not disengage 100%.

Post by Bruce W » Thu Jun 10, 2021 7:10 pm

The nuts and lockwashers are wrong. The correct nuts are thinner than normal, and the correct lockwashers are thin, stamped star washers.
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Re: Clutch disk assy. does not disengage 100%.

Post by dinof » Thu Jun 10, 2021 9:45 pm

SierraJeep wrote:
Mon Jun 07, 2021 11:37 am
Gentlemen,

Thank you all for your help and comments.

I have one T84 clutch pressure plate on order with Ron. I'll send an update after received and installed.

Andrew
Best thing you can do. His clutches work just fine.
Dino Falabrino
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Re: Clutch disk assy. does not disengage 100%.

Post by JAB » Fri Jun 11, 2021 4:45 am

Bruce W wrote:
Thu Jun 10, 2021 7:10 pm
The nuts and lockwashers are wrong. The correct nuts are thinner than normal, and the correct lockwashers are thin, stamped star washers.
BW
Maybe it's just the picture, but the nuts and bolts both appear to be over-sized. If so, even the proper clutch disc won't help. You need to verify that first, as that may be the root of your problem. I hope the crank wasn't drilled out to accept larger diameter bolts, and if it was, I hope you can find hardened jam-nuts and proper lock washers to safely hold it all together in balance.
-Jeff

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Re: Clutch disk assy. does not disengage 100%.

Post by Wolfman » Fri Jun 11, 2021 6:51 am

Looks like the dowel bolts are straight instead of tapered bolts.
This was done if the flywheel has been replaced.
To insure the two dowel bolts lined up properly with the holes in the new flywheel, the tapered dowel bolts were removed. The new flywheel installed.
The 2 dowel bolt holes were drilled & reamed oversized, all the way through the crank flange and straight dowel bolts were used.
There was a clearance issue with the nut height, to avoid what you have here.
Instead of normal nuts, thin nuts, like jam nuts were used on the dowel bolt.
Once installed, the nut should not be any taller than the threads on the dowel bolt it is screwed on to.
Obviously not the case in this picture.
If the flywheel has been resurfaced, nut height can be more of an issue.
Mike Wolford
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Re: Clutch disk assy. does not disengage 100%.

Post by SierraJeep » Sat Jun 12, 2021 9:01 am

Good morning Gentlemen,

First I want to express my thanks to everyone helping me. You’re all tops in my book. You may have guess it but, I’m no “gear head”. This is the first time I’ve never tried restoring a vehicle. Its been a learning experience the whole way.

Some additional history on the motor. It was rebuilt by the previous owner but never reinstalled. It starts up and runs like a champ but still needs a standard tune-up. It has a Willys head but, no clue who made the motor. I suspect it's a Willys CJ2. Is there any way I can track down the year and manufacture? Flywheel was resurfaced. A T90 was installed way back when and my guess the flywheel I’ve been using was used with the T90. Don’t know if that matters or not with the T84. Sounds like it does?

So, I removed the flywheel and posted more pictures. Flywheel (front & back) and the bolts on the crankshaft. I did noticed there is no way to remove the bolts unless I disassemble a more of the motor.

Looking at the bolt pattern I couldn’t tell if it’s correct or not. I pretty sure the flywheel doesn’t have the tapered bolts and the dowels are missing.
Suspect, as Mike said, they were drilled out. Not knowing the year or manufacture of the motor does it have to have dowels?

A big question is, should I treat this motor as a post WWII motor? Going back to I’m no gear head…What are my next steps? I.e. if you were in my shoes what would you do next?

Hate to ask a stupid question but, what is a “jam nut”?

Andrew
Attachments
Flywheel Back.jpg
Flywheel Front.jpg
Bolts passenger side view.jpg
Bolt Pattern on Crankshaft.jpg
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Re: Clutch disk assy. does not disengage 100%.

Post by JAB » Sat Jun 12, 2021 9:21 am

A jam nut is a nut that is thinner in profile than a standard nut for a given size. They're also called thin nuts. A taller nut than standard is a high nut. A nut that's wider across the flats than standard for a given size is a heavy nut. For some sizes, like the 7/16-20 used on the U-bolts (springs and axles) they come in several heights depending on application. Really tall nuts are called coupling nuts because they're used to couple two threaded bolts or rods. You can usually find all sorts of info like this on the McMaster-Carr website at the beginning of a certain section. https://www.mcmaster.com/nuts/thread-si ... Box=o-ring

It looks like two of your bolts are shoulder bolts that might be used in place of the tapered dowels. If the holes were drilled accurately there's nothing wrong with that. If it were me in this situation, this far into things, I would do some measuring to see if a grade 5 or 8 thin nut and different (high quality and rating!) lock washer (or loctite?) would clear. Maybe just switching to a differnet brand clutch would work. Assuming the flywheel was indexed as far the timing marks I hope you marked it so that you don't install it 180 degrees from where it's supposed to be. It's not a deal breaker, but you should be able to view the timing marks at the right time/place (when piston number one is at TDC on the compression stroke) through the inspection hole after it's all together.
-Jeff

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Re: Clutch disk assy. does not disengage 100%.

Post by Wolfman » Sat Jun 12, 2021 10:48 am

Quickest way to identify assembled war time engine blocks from post war engine blocks is the front timing cover.
The war time engines are chain drive cams. The cam is held in the block by a short rod, with a rivet type head on one end, that fastens the rod to the timing cover and a spring & plunger in the front center of the cam pushes against this rod, to hold the cam in place.
If you look at the front of the timing cover, right where the center of the camshaft is, you can see the rivet head that holds the rod to the timing cover. On the outside front of the cover.
If there is no rivet head on the timing cover, you have a post war, gear drive cam.
Another way is the engine serial number.
The war time engines have the serial number on an oval pad, cast in the right side of the engine block, ( as you are sitting in the drivers seat ) at the top, front of the engine, just below the head gasket. Behind the oil filter.
The post war engine serial number is on the top front of the engine block, right in front of the cylinder head & head gasket. Above the water pump.
You have the larger, straight shoulder dowel bolts. These are replacement or later type.
No other dowels are used.
And yes, you have to remove the oil pan and remove the main bearing cap to get these dowel bolts out of the crankshaft flange. But I don't know why you need to. What you have is OK.
And use the thinner external tooth type lock washers under all 6 nuts.
Do not use split type lock washers. They are too thick.
Mike Wolford
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Re: Clutch disk assy. does not disengage 100%.

Post by SierraJeep » Sat Jun 12, 2021 1:14 pm

That settled that. It is definitely a post WWII engine. No rivet and Ser # is above the water pump. Question is, is it compatible with the GPW T84 and all else GPW?
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Re: Clutch disk assy. does not disengage 100%.

Post by SierraJeep » Sat Jun 12, 2021 1:15 pm

And Mike, thanks for all your help.
Andrew
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Re: Clutch disk assy. does not disengage 100%.

Post by JAB » Sat Jun 12, 2021 1:29 pm

SierraJeep wrote:
Sat Jun 12, 2021 1:14 pm
That settled that. It is definitely a post WWII engine. No rivet and Ser # is above the water pump. Question is, is it compatible with the GPW T84 and all else GPW?
Yes.
-Jeff

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Re: Clutch disk assy. does not disengage 100%.

Post by SierraJeep » Sat Jun 12, 2021 6:19 pm

Jeff,

Thanks for verifying. I'll order the jam nut today. The new pressure plate arrived yesterday. Will reassemble once I get the nut. Will post the results when finished.

Appreciate all your help too.

Andrew
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