Farmall M Clutch

Okay guys so I?m at a loss here, I posted a few times
regarding the clutch on my M it?s got new everything. The
problem I was having was it just grabbing and shaking the
tractor when letting clutch out slow and it?s not just me a few
other experienced drivers said it was the same for them. But I
can?t figure this one out I checked my pressure plate finger
height it all seems to be so close I cannot see any difference
between the three. If I give the tractor more throttle the clutch
lets out smoother the more throttle the smoother it is. The
brakes are not grabbing I unhooked the brakes today and
drove it without any tension on the brake drums so I know
nothing is binding up there. One thing I haven?t checked is the
pressure plate finger height from the flywheel but I?m not sure
what that even is suppose to be. Now this clutch isn?t
unbearable but before I had the flywheel resurfaced and
rebuilt the motor the old clutch parts was smooth as silk. So
that brings me to the question of if it just needs time to break
in and if so how much time? You can see from the pictures
how everything looked when I took it apart to inspect before I
put it back together.
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Do you feel vibration, shaking, etc. in the peddal itself? An M is a pretty heavy tractor, especially if you got fluid in the tires which I do. It takes alot to get an M moving from a dead stop. My M (the tractor itself) shakes a little when I let out on the clutch from a dead stop. Probly from some minor clutch slippage untill the tractor gets to rolling. Or maybe caused by some play in the gears, shafts, differential. It's like the clutch slips, grabs, slips, grabs untill the tractor is moving. It does this worse in the higher gear your in. Not as bad in first, or maybe not at all in first. And worse if pointing up an incline. Does your tractor do this if you try to shift gears while tractor is in motion?? Like shifting from 3rd to 2nd without coming to a stop. Or shifting from 4th to 5th while rolling down a hill. Or pushing in on the clutch to shift Into nuetral. If it does it then, then you can rule out that the shaking isn't normal.
 
Yes I do feel shaking in the pedal itself. And my tractor is doing it even in first gear I took a video of it but I?m not sure how to post it. It?s like the tractor will begin to engage smooth from a dead stop then as it?s already rolling the tractor will begin to shake and I can feel it in my pedal. I realize that this is an old tractor and one can expect some stuff to not be like a modern tractor but it?s got all new clutch parts. The old clutch and pressure plate were smooth it never shook from first even through taking off in 5th from a dead stop. I feel like maybe it needs to break in and it will smooth up some. The flywheel maybe needs to get that glaze back on it to smooth up?
 
that machine job don't look like the clutch and pressure and flywheel are engaging over the whole surface. this is where you need to slip it a bit under load to get it worn in. also I have a feeling you don't have that 4 hole connecting link with the tapered bolts installed correctly.
 
Two things strike me. The first is that friction disks for normal stock (old) tractor use should have organic composite surfaces. Dark grey with coppery strands/fibers in the material. between these two friction surfaces should be a cushion spring (see picture). this spring is designed as a wavy plate that smooths the application of the pinching on the disk. The one shown is from a car that had the friction material shred off of it, but shows the cushion spring well. If your replacement clutch disk was made as a "puck" style, it may not have any cushion at all.
Here is the essence: A cushion allows soft easing into the application of the forces. It evens out minor surface or finger issues and causes (important) the pedal to feel the progress of engagement over a greater distance of travel (maybe as much as 3/4 of an inch of pedal travel. With no, or little, cushion in the disk, the pedal might travel no more than 1/8 inch from full release to full drive. When operating the tractor, the movement of the tractor and the feel of the pedal is very different between the two types. I put a puck type clutch in a Subaru i owned (quite a job to do) and had to replace it within 1000 miles because it was jerky and could not be controlled for maneuvering in a garage or parking.
There is also a set of torsion springs that cushion engagement. these are spaced around the center and also assist in making engagement smooth and reducing jerking.
I also agree that your surfacing shows irregular machine marks, not best. I also see that from my view point, the pressure plate mounting surface was not machined to provide the mandatory offset for proper pressure plate pressure. This offset is the distance between the surface where friction happens, and the surface "rim" where the pressure plate bolts on. There are no machine marks there.
Jim Good luck.
 
This is a picture of my driveshaft coupling hope it all is well and yes I did put all the nuts on after the picture was taken. Thanks
cvphoto23615.jpg
 
Thanks for your detailed reply I have noticed that the engagement for the clutch is very brisk it?s not a long engagement like on my Tacoma truck I drive everyday which is very smooth. Not sure on clutch in my truck I?ve never had to replace it yet. Would adjusting the fingers to protrude closer to the throwout bearing allow for a longer engangement to release the clutch? I?m asking because the clutch disk I had in there is a dark grey fiber disk with the strands and I had it in my tractor before I resurfaced the flywheel and it was smooth then I replaced the pressure plate resurfaced the flywheel and put the clutch disk in that was ?new? but had some hours of wear on it. So whenever I tore the driveshaft and pressure plate back out I replaced the disk so it?s a fresh disk on the flywheel. The first picture is the old disk and the next is the new I installed that is currently in the tractor. Also the pictures you spoke of for some reason I cannot view them. Thanks Trent
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Here is another try at the image Both of your disks have no torsion springs at the center, and do not look like they have the cushion springs either.
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I see now yeah I didn?t know that they offered that for a Farmall M is there anyway to get a longer engagement by pressure plate adjustment?
 
Your discs look like normal M clutch discs. Never had any torsion spring center or other springs between facings to help with clutch engagement issues.

Since the advent of no or very little asbestos in brake and clutch facings, the facings have become more aggressive. At best, a lot of M's were a little jumpy at low speeds from day one, not all but enough. It did not improve with the newer linings available. I would try burning it in a little.
 
No. Increasing the length of the clutch actuating arm (outside of the tractor at the cross shaft by 1.4 of the length) could make it a longer engagement period. No guarantee. Drawing to be shared in a few minutes. Jim
 
Putting a bolt through the middle hole and through the lever(where the clevis is now), then another bolt through the top hole to keep it from turning on the existing arm, then putting the clevis through the bottom hole will extend the lever, but not make it a permanent change that would require replacing the cross shaft if removed. Jim
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One of these extensions makes the clutch push a lot easier making for better control, for my 70 year old clutch leg anyway.
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I found some old literature on the adjustment for the pressure plate my understanding is that the cross shaft is disconnected from the clutch shaft then at the extreme rear position the pressure plate fingers should have a 9/16 gap mine is somewhere are 14/16? then once that is adjusted you adjust the clutch pedal for free play and check your gap then for 3/16? am I reading this right? Thanks
 
Maybe the issue is one I pointed out in my first response. If the flywheel was machined, and the step from the pressure plate mounting surface was not machined to maintain that depth specification, the clutch will not work correctly. It only takes .050 of incorrect depth to throw off the fingers the 5/16 you are discussing. When I look at your images, I see no machine marks on that flange where I would expect them. That is basically all I can suggest. The person that machined the flywheel must know the spec, and needed to make it within spec, or it fails. Jim
 

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