Allis CA 1954

First time user,

I am trying to figure out a slipping hand clutch on my 1954 CA. It's go to tractor for snow removal.
The tractor runs fine but will not move on level ground or creeps very slow.
I suspect a weak hand clutch assembly.
Any thoughts on repair costs or suggested fixes on the old bugger would be appreciated?

Orange hat

The parts are still available from Agco new pressure plate springs,and clutch plate.But they are high dollar.I got new springs was $7.00 a piece,the clutch disc I'm in the $250 t0 $300 range.But its been 6 or 7 years ago.

I can't remember if Rick Corder is here or not but I know he is on the other AC site. He does clutch work and might be able to help with parts.
AaronSEIA

I just did the same clutch in a ED-40. When you look in there, down the axle with the housing and
reduction gear removed from the tractor, there are 6 socket head capscrews, these take the clutch
off of the brake drum and you can remove it easily. The CA manual has information. So does the
Unofficial Allis forum. One thing the manual doesn't say is when the new clutch is together you
check the amount of clearance for release. If it is excessive you bolt the part with the 3
fingers where the six capscrews go to a milling machine table and take some off, the clutches
work better without excessive clearance here. On the other forum there was good pictures. The CA
manual has a good exploded view too and specs for the springs. Mostly you clean and inspect,
replace worn balls or ramps they roll on, warped parts, and worn clutch disc. The clutch disc is
supposed to be close to .193 thick, if it is not close that could be the problem. Or the springs
are weak, broken, or the self energizing balls and ramps pitted or out of round, as I said it is
mostly cleaning and inspecting. Same for the release mechanism that the lever actuates. You need
about 2 1/2" of free play in he lever too, if you have none this isn't going to help it either.
You can e mail me if you want, [email protected] Just put something like Allis Chalmers clutch
in the title so I don't delete your message with the rest of the junk. Tom

Hi All,

Thank you for the great feedback and insight on the repairing the hand clutch.
I will start working on it this upcoming weekend.

Much appreciated,

Greg

4WDTom gave very good advice!! I have done two of these and did as Tom said, the only thing I will emphisize is to look at the
springs carefully, when I compared my old ones to new ones the old ones were about 1/4" shorter as they had lost their strength.
Some tractor pullers will bolt the clutch together making it one piece. You could do this if you don't want to spend money fixing
it but that I wouldn't do that if it was my tractor.

I look back in my information and the clutch springs should be 1 1/4" long free length. Replace if 3/32" short.

Now the bit about milling the clutch body. Put the body on the bench with the 3 fingers up. Put it together with no springs. Put the top plate on, the one held on by 6 SHCS Measure the gap between the clutch disc and the top plate, it is easy to do this without the springs in, put them in later. You only need .020 gap here, this will allow the clutch to release later. If you have more, bolt the body to a mill table with the 3 ears up and mill off some to reduce the gap. I guess it could be done on a lathe if you bolted it to a face plate, or bolted it to a plate and bolted the plate to a face plate. If you are going to reuse some old parts probably this gap will be on the large side. When you reduce it keep in mind that someday you may have all new parts and not want the ears too short. I guess some folks grind these ears, but I think it would be very difficult to get a hand grinding job even. If you cut too much off shims could always be made to shim it back out in the future. My note says the total clutch disc measures in at close to .500, the linings are the .193 each measurement, so you have two linings riveted on, and the thickness of the metal disc, total .500. Again, with the clutch trial assembled on the bench with no springs you want .020 (or not much more) between the clutch disc and the top plate that bolts on.
All this will make more sense when you have the clutch on the bench, apart, and begin to understand how it works, torque from the axle causes the balls to roll up their ramps and make the clutch self engage harder and harder the more torque is applied, the springs don't do it all.

When you do the release mechanism it is similar to the clutch as balls roll on ramps to move the throw out bearing when pulling the lever. Adjust so you have a gap between the throwout bearing and clutch, this about the 2 1/2" free play at the end of the lever.

This is also a good time to replace the oil seal in the differential which is under the cover exposed when you remove the release mechanism from the differential. It is easy to do, just keep track of the shims and put them all back, they are the differential bearing adjustment.

Good luck, it isn't all that bad after you get into it a bit, just different from the clutches we are all used to.

I carried the clutch unit , from my 52CA, into a clutch and brake rebuilder in Tacoma Wa., and picked it up, and installed it, and It works great.

I grew up on WD's and WD-45's, so my experience with the "CA" hand clutch is kind of limited. I've rebuilt one in all my years of wrenching. This much I will say.... it is no where nearly as tough or durable or reliable as the WD/WD-45 wet hand clutch. It shouldn't ever be used to start motion on a heavy load (plow, disc, etc). I would never use it when in 4th gear... ever. It was a feeble attempt by the AC engineers to give you live power at an inexpensive price. Use it wisely and cautiously for longest life is the best advise I can give.