The dreaded clutch fork pin again.....

Well it finally happened to me. Sheared the taper pin on the cross shaft and now i have the hacksaw out because it is good and stuck! I may be grasping at straws here, but the collective wisdom of this forum has saved me before! Any last ditch ideas here guys???????

I understand that using a center drill ( 5/16 or 3/8 ?) to start, and then continuing with a normal drill, one can drill a hole in the fork on the opposite side and then punch the broken pin through.
Bob

Mentally extend a line through the center of the pin and to the surface of the fork. Use a center punch and hammer to put a pop mark on the spot.

I used a much smaller drill, like maybe 3/16" and no center drill. Start the hole with the drill held perpendicular to the surface of the fork (which is way out of line with the pin), then once you've penetrated by a drill width or a little more, gradually turn the drill so you are drilling directly towards the pin.

Then turn the fork into it's original alignment with the shaft, and knock the remains of the pin out with a 1/8" pin punch through the hole you just drilled. The fork should be reusable, the shaft may or may not (depending on other damage to it).

When you are ready to reassemble, fit the fork & new pin to the shaft with the shaft outside the bellhousing. Then drill a 1/4" (or very slightly smaller, ISTR I used a 'D' size drill) hole through the fork and shaft, roughly on center to the shaft but at right angles to the taper pin. Then remove the pin & fork and install in the bellhousing. Once it's installed, drive a 1/4" Grade 8 bolt into the hole and fasten it with a Nyloc nut. Check to be sure the protruding end cannot foul on the gearbox front cover (I had to trim the bolt I used).

I got this idea from Ken Gillanders at British Frame and Engine, but it's been published in many places so I don't know who original credit belongs to.

ok,, thanks for the info gents. i will give the drilling a try, and if it does not work i am just back to where i started ( hacksaw in hand )
I had read somewhere about the second pin or bolt to retain the fork ( and i am toying with the idea of just running a bead of weld on it) , and also using a TR4 shaft with the grease fittings allready on it to help with bushing wear.

thanks again,

Mitch

IMO the bolt is actually better than welding. Much easier to disassemble next time, and I've seen welds break (welding cast iron is tricky enough, but welding cast iron to steel is even worse, or so I'm told).

Hmmm, somebody's been riding their clutch. Ask me how I know.

IT worked! Used a 7/64ths drill bit and a nail for a punch and out popped the remnants of the pin. Cross shaft looks like it is in pretty good shape, just a touch of wear on the drivers side where it runs in the bush. Im going to re-bush both sides with longer bushings and i should be away to the races..................

Jedi Knight, the welding comment was just made in frustration, yes it would be quite difficult ( next to impossible for me ) to get cast to attach to steel.
I will be going with the second bolt modification when it gets assembled...

cheers,

Mitch

Well, some people do weld them, and sometimes the welds do hold ... I had to take one apart just a few months ago that had been welded. Hated to take a cut-off wheel to that shaft, since there was nothing wrong with it, but I needed to get the gearbox apart.

There is supposed to be a pin that keeps the TOB carrier from rotating against the fork pins ... the design used on the TR6 and Stag actually "rides the clutch" a bit all the time whether your foot is on the pedal or not. The TOB is loaded into the pressure plate by a spring in the slave cylinder and is supposed to always spin.

At any rate, not my photo /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

My first TR6 had the shaft welded to the fork. It wasn't welded in the proper orientation to the lever on the end of the shaft, and even with the adjustable push rod, it was impossible to have the clutch operate properly. The third time (in a few weeks) that I removed that transmission trying to figure that out, I cut the shaft with a torch (threw it away and replaced it) and never had another problem (with the clutch). -And I didn't use the adjustable push rod.

The TR6 I have now has the "second" bolt method, but also had a hole added though the end, and "air-craft" type wire through it, tied off so the bolt/nut can't back out. It looked well done, so I didn't modify it when I rebuilt the transmission.

Another 'fix' that has worked well for me is to just replace the tapered pin with a two inch long, 3/8-24, grade eight bolt. Has worked faithfully on both race and street application. Just drill out the fork and cross shaft with a 21/64" bit and run a tap through the assembly as a unit. Obviously drill deep enough to handle the bolt. I usually just use a lock washer, but you might feel better about using one of the fasterner cements or drill out the bolt head for safety wire.