Cub clutch linkage issue

Fri Jul 01, 2016 10:10 am

I got the machine for a song, knowing there was a clutch problem, and when I split it, I found the clutch fork had gone way forward, hit the finger adjustment lock nut and spun it off. That might have caused the clutch fingers to be way out of adjustment, because they were way off, and the TO bearing had a strange lopsided wear pattern on it.

The clutch was actually in good shape re: wear, so I set it up with correct finger clearance, fixed and staked the nuts, lapped a sixteenth of an inch off the face of the TO bearing flat, and it all went together nicely. The TO bearing still had about 1/4" of Graphite protruding from the carrier. Everything looked good. So, assembled it , but then noticed there's not enough adjustment available to get clutch to TO contact or clutch action.

Had shoulder surgery, so left the project until now. Just fired up the engine, so I know she's a good runner.

So, what are my options?

Why did the clutch fork go so far forward? I thought over 3/16" TO bearing material remaining was adequate. Everything looked right. Did someone stomp the heck out of the clutch and bend something? Is there another clutch rod adjustment somewhere?

Must split her again?

C

Re: Cub clutch linkage issue

Fri Jul 01, 2016 10:24 am

There are 2 different clutch rod and pedal systems, so knowing which you have would be helpful. The first year and a half or so had a turnbuckle where the rod attached to the TO hanger, and were a real pain to adjust. The rest have an adjustment on the clutch pedal you loosen to adjust the travel. The adjustment on the pedal is a bolt just under the floor plate (takes 5/8 wrench) you loosen that is in a slot. When it is adjusted correctly the pedal will have about 1 to 1 1/4 inch travel before the TO contacts the fingers.

Re: Cub clutch linkage issue

Fri Jul 01, 2016 12:06 pm

1961Cub...a new one, the second description. The bolt on the pedal is maxxed out on the travel. I put a bolt in the slot to fill it, and there's now almost no free play.... but now there's also no clutch motion. It seems to bottom out on something. When I turn the engine over, the clutch pedal bobs up and down, so really, I now know I've got some big issues in there. Something's bent up. Someone stomped it.

I just don't know what it is.... Luckily, I've not reassembled the entire tractor yet...just enough to see if I can run the engine off a small jug of gas.

I'll yank it apart and get back to y'all re: what these parts should look like.
Thanks for now..
C

Re: Cub clutch linkage issue

Fri Jul 01, 2016 1:11 pm

IMHO splitting the tractor is the best way to remedy a clutch problem of any magnitude….I've been frustrated trying to work thru the peak hole enough to last me a lifetime :lol: :lol: ….Splitting it and seeing what you got is my remedy for fixing clutches…You're on the right track….IMHO….Dave

Re: Cub clutch linkage issue

Fri Jul 01, 2016 4:48 pm

Righto...split em enough times, and it's no big deal.

Just will be real careful this time and not assume anything...i just wonder how the clutch got into this condition?

C

Re: Cub clutch linkage issue

Sun Jul 03, 2016 3:42 pm

Okay, split. took 20 minutes. I looked at the clutch fingers before I took the pressure plate off. There was lots of free play and travel from the fully out position to the point where they should begin to work as levers to release the PPlate. So that explains why, at least partly, why I could not adjust the clutch linkage far enough to remove freeplay, let alone activate the clutch, and when I made a jury rig fix of the adjustment, when the free play was gone, so was the clutch operation.

So, before I pulled the PPlate, I adjusted the fingers, turning the adjusting screws in, which brought the fingers out...that made sense toward an operating clutch and cure of my problem. Then pulled the PP, watching the fingers come up even further, which I would expect. Now I have a PP with the fingers measuring 1.5/8"-1.3/4", which is not correct. I had originally set them to 1.250 +/- .005.

Any hints? My Yankee frugality kicks in when I think that the solution is just to throw money into a new clutch assembly and be done with it. My mechengineering also doesn't want to miss out on a good whodunit case resolution.

Re: Cub clutch linkage issue

Sun Jul 03, 2016 8:51 pm

1.25" with the clutch/pressure plate installed on the flywheel. Check for wear on pin/mounting holes on the lever/mounting hole on the pressure plate.

Bill

Re: Cub clutch linkage issue

Sun Jul 03, 2016 10:02 pm

ccaissie wrote:Now I have a PP with the fingers measuring 1.5/8"-1.3/4", which is not correct. I had originally set them to 1.250 +/- .005.


Once you unbolt it from the flywheel the measurements change, as Bill said you only adjust them to the 1 1/4" when bolted to the flywheel.
My first time out I thought I would be smart and bolted it to a flat plate on the bench for easier adjusting. I forgot there is a lip on the flywheel that changes that measurement once bolted back on.

tim

Re: Cub clutch linkage issue

Tue Jul 05, 2016 12:40 pm

Very good sirs....I had set it to 1.25 on the bench....Now I know.

This solves a bunch of other issues. The TO bearing face was cleaned up by lapping it on a flat plate. When I had it installed the first time, I had the engine spinning, etc., and this made a circular mark on the TO face, but it wasn't concentric. It was lower on the face because the TO fork had to travel so much further forward, it swung upwards....bingo.

Re: Cub clutch linkage issue

Tue Jul 05, 2016 9:24 pm

ccaissie wrote:This solves a bunch of other issues


Hopefully it solves them all, glad you got a handle on it now.

good luck

Re: Cub clutch linkage issue

Thu Jul 07, 2016 6:31 am

ccaissie wrote:..... The TO bearing face was cleaned up by lapping it on a flat plate. When I had it installed the first time, I had the engine spinning, etc., and this made a circular mark on the TO face, but it wasn't concentric. It was lower on the face because the TO fork had to travel so much further forward, it swung upwards....bingo.
Even with your oops, there's a positive in there for others. That non concentric ring on the TOB is the perfect visual of why NOT to use an automotive style TOB.

Re: Cub clutch linkage issue

Thu Jul 07, 2016 11:15 am

My preferred (lazy) way of setting finger height is to also remove flywheel and put on bench and reinstall disk and pressure plate. I then use some door and window shims to level the flywheel on the bench, and adjust one finger to the height I want, then use a small torpedo level to set the rest to the same height. When you put everything back on the tractor it should all be preadjusted. I have done that a lot of times, but did have trouble with it one, though I never did figure out why I had to readjust it that time. I am getting a little old and a lot stiff from arthritis, and laying under a tractor trying to adjust those fingers through the access hole is a real PAIN.

Re: Cub clutch linkage issue

Sun Jul 17, 2016 7:37 am

I also spotted the cause of the clutch pedal pulsing in and out. The front surface of the TO bearing showed a circular wear mark where it contacted the fingers. It was Lower than the center, and also TO THE RIGHT of center. Lower location was because the TO bearing had to swing so much further forward to engage, but the off center mark was because of a BENT fork. I looked at the fork and saw one side was bent in about 1/4" which would explain the off-center wear mark and the pulsation.

It's obvious once you see it.