General Tech Clutch Fork and Broken Pin

[KVH]

This is a very old subject about the clutch fork.

I'm rebuilding my latest 4A. I'm looking at my transmission and know I'll be replacing the front spigot cover and the clutch plate--and I'm wondering what else I ought to replace.

I'm trying desperately to recall why on my last TR Transmission I cut and removed the clutch fork shaft. Maybe I was just wanting to put a new pin in the fork, and I do recall that I simply could not remove that old fork, so maybe that's why I cut the shaft.

On the one I'm working on, however, the shaft and fork look fine, and pin appears fine, too. The release bearing and sleeve slide right out with the shaft in place, which I assume is normal.

Any reason why I need to replace the bearing, sleeve or shaft while I'm at things?

 

[TR3driver]

If the bearings & shaft are really OK, then I'd reuse them. But the taper pin is simply a poor design IMO, and fails from metal fatique rather than wear. It probably will look fine right up until it breaks. After having the joy of removing the gearbox just to replace that dang pin, I'll never put another one back together without some form of reinforcement.

FWIW, I use the 1/4" bolt method. Simple, easy and effective (don't forget to trim the excess threads from the bolt). But the Buckeye article outlines some other methods that no doubt would work just as well.
https://www.buckeyetriumphs.org/technical/clutch/ClutchShaft/ClutchShaft.htm

 

[Geo Hahn]

I removed the pin on mine when I had it apart to repair the clutch. The pin had a distinct bow in it, I can easily imagine it would have eventually failed.

I replaced it and, like Randall, added a back-up bolt.

 

[CJD]

The last shaft i did had to be cut because the PO had welded the fork to the shaft. At first I thought it was a shoddy idea. But after thinking about it...and seeing how cheap the fork and shaft still are at the big 3 vendors...I realized it's really not a bad idea! Once done the problem is solved for good, and it still only took a minute with a 4" grinder to remove the old parts.

 

[CJD]

Oh...one last though after reading your post. I've not had a release bearing be able to slide off the fork without removing the release shaft. I'm not sure if that is due to the design of the particular release sleeves I've worked with or not. Yours may be just fine, but take a good look at the fork pins that ride on the bearing. They may be worn flat, allowing the sleeve to slide off. They are round when new.

 

[KVH]

Oh...one last though after reading your post. I've not had a release bearing be able to slide off the fork without removing the release shaft. I'm not sure if that is due to the design of the particular release sleeves I've worked with or not. Yours may be just fine, but take a good look at the fork pins that ride on the bearing. They may be worn flat, allowing the sleeve to slide off. They are round when new.

Does anyone know? Mine just slides right off without the slightest resistance as I tilt the fork forward.

 

[CJD]

Check the 2 pins on your fork. They should be perfectly round, as in this photo:




If you look at this pic, the back ring of the throw-out sleeve hits the fork before the sleeve will come off the tranny nose:



If your fork pins are round and nothing else looks bent or mangled...then don't sweat it. I assume there have been variations in sleeve and fork design that alter the clearances and may allow the sleeve to slide right off. I just haven't encountered them so far?!?. I only bring it up as a reason to inspect the pins for wear, to be sure.


Addendum: As I sit and look at the pics above, I realize that a couple minutes with a grinder on the end of the fork prongs would allow my fork to rotate farther without binding too. I think I may grind those tabs off next time I'm in the tranny, as it would save a lot of time having the sleeve come out without removing the whole fork assembly!

 

[TR3driver]

Does anyone know? Mine just slides right off without the slightest resistance as I tilt the fork forward.

Mine have always just slid off. But IIRC my fork looks a little bit different than John's does; so maybe it was an undocumented production change at some point.

I know they changed the gearbox front cover without documenting it, as the TR2-4 cover will interfere with the TR4A clutch if you don't cut about 3/8" off the end. Works fine until you step on the clutch, then the fingers close up and try to grab the tip of the cover.

PS, the workshop manual says to remove the bearing before the shaft & fork, so they must think it slides off too.

 

[KVH]

What would I do without this forum!