TR4/4A TR4A Clutch Fork and Shaft

[KVH]

Gosh, if I could only get back to the Overdrive.

My latest distraction is the clutch shaft. It's wobbly at the driver's side. That makes me conclude I'll need to remove the tapered fork pin, shaft and bushing and put a new one in. Is that correct when there is play in that shaft?

I really thought the PO had gone through the car somewhat, but I keep finding things.

I'll read the Buckeye and VTR material on the clutch shaft and fork, but any words of advice here first?

Will I likely snap that fork pin, and should I try an eight point socket on it first?

Finally, folks, how will I know if the throw out bearing is good or bad? It looks fine by appearances, but what am I to look for?

thx

 

[trrdster2000]

KVH, the shaft does have bushing on both ends and can be replaced, your Bentley (Haynes), has the scoop. If you are in there, replace the throw out bearing and watch out for the pin on the carrier.
As for the taper pin, lots of oil for a day or two and no jerky move when removing. I find a large crescent wrench gets a big bit on it.

Wayne

 

[TR4nut]

Replacing the bushings isn't too bad, certainly easier than what you are doing with the overdrive! I'd be prepared to replace both bushings. If the passenger side one needs replacing, and it is the cutout style like on a TR4, then I'd recommend buying the bushings probably from Moss or VB. Not bashing TRF, but the bushings I picked up from them recently were made of oilite or some similar material - and were very brittle. The bushing with the slot cut in it could not be installed (I tried twice, carefully).

 

[TR3driver]

To test the TOB, lay it on the (clean) floor with the clutch side down, then stand on it and do a pirouette. It should spin easily and smoothly with your weight on it. Any roughness or binding calls for replacement.

Most folks replace them every time as Wayne says, but I don't. I've only been bitten by a bad bearing once, and that time I accidentally put back the wrong one (untested and not the one I took off). Even then it lasted something like 30,000 miles.

IMO it's worthwhile adding a grease zerk for that bushing, if it doesn't already have one. You can either drill the shaft as the earlier cars had from the factory, or drill and tap the housing & bushing.

The earlier cars used a wide brass bushing that I like better than the narrow steel one used on later cars. Stanpart 36998. Or you can install two of the narrower ones, with a small gap between to help hold the grease.

I also advocate adding a bolt to reinforce the taper pin, as they sometimes fatigue and break. There is a detailed discussion (including other methods of reinforcing) on the Buckeye Triumphs site (where this photo was stolen)

 

[TR3driver]

If the passenger side one needs replacing, and it is the cutout style like on a TR4, then I'd recommend buying the bushings probably from Moss or VB.

Better yet, just use the one without the slot, and leave out the locating pin as on the later cars.

 

[KVH]

Better yet, just use the one without the slot, and leave out the locating pin as on the later cars.

Sounds good. Not sure what you mean, though, by "leave out the locating pin."

Mine somehow does look "cared for." There is what appears to be a new taper pin with a hole drilled in it, and it's lock wired to the shaft. Then, there is an extra fastening bolt which I believe is a locating bolt right in the front center of the fork.

Long ago I watched a guy drive out a bushing. He used a small chisel type tool that first curled or sliced the softer steel. Then he drove it out. In this case, do I just use a 1 inch pipe and drive it out?

 

[TR3driver]

I'm pretty sure yours is the later style anyway, Marc, so no need for you to worry about the pin. The slot & locating pin ended very early in the TR4A run, at CT50124 according to the Moss catalog.

Nelson wrote that 1/2" pipe would do to knock the bushings out, but I use a mandrel that I turned on the lathe.
https://www.buckeyetriumphs.org/technical/clutch/ClutchShaft/ClutchShaft.htm

 

[KVH]

Darn. My transmission is apparently the older model. Which explains why my OD (1374) is also the older model.

I removed the TOB, grease nipples, and both the locating bolt and taper pin came out easily. EXCEPT that the taper pin appears that it's been broken for years. Only 3/4 of it came out, and the fork and shaft now cannot be removed.

I assume this means careful hacksaw exercises.

BTW, the shaft is worn a bit anyway (maybe .002), so I may have needed a new one.

thx

 

[TR3driver]

I got mine out without a hacksaw, which at least allowed reusing the fork (the shaft was worn worse than yours). Mentally project a line through the center of the pin; and put a punch mark in the fork arm where the line would come out. Start drilling a hole at that point, perpendicular to the surface of the fork (which won't be towards the pin). Once the hole is started to a depth of 1/8" or so, turn and drill towards the pin until the hole breaks out in the cavity. Then turn the fork to approximately its correct position, and use a pin punch to drive out the broken end of the taper pin.

https://www.buckeyetriumphs.org/technical/clutch/ClutchForkPin/RemovingBrokenClutchForkPins.htm

 

[KVH]

I tried. That taper clutch fork pin will not come out. My fork actually had a hole already, but that pin looks beat to a pulp already, as if someone once worked on it. If I hit it anymore I'm concerned I'll damage the transmission housing.

Anyway, I might try cutting the fork off instead of the shaft.

I'm curious about the spigot of the transmission that protrudes into the front bell housing. I can grab it and wobble it in its housing. Like about a full 1/8 inch each way. Is that normal?

Thanks.

 

[JerryVV]

That seems excessive

 

[hondo402000]

are you talking about the input shaft or the part the release bearing slides on?

if you are talking input shaft, sounds like the front bearing is really bad

 

[TR3driver]

Either way, not normal.

 

[KVH]

Yes, the wobbly part is Item 8, shown below, being the very left hand "end part" of the input shaft.



Guys, this is getting to the point of two Moss/TRF orders per week, and I'm still not there. Am I going to have to rebuild that transmission next!

 

[TR3driver]

Seems like the wise choice to me. The OD shares oil with the transmission, so whatever bits of metal were floating around also got into the transmission. Those big bearings rarely fail, but it sounds as though yours is badly worn.

On a side note, the diagram above is for a 3-synchro box. Do you really have a crash box in your 4A?

 

[hondo402000]

well if its out it would be wise to. Its less expensive to rebuild a working tranny than one that has locked up, In my opinion

Hondo

 

[KVH]

I guess I better check what I have. It's pretty much a standard TR4 transmission with the 22/1375 OD. I just took that photo out of the Moss catalog, and I see I shot the wrong one. Here's mine:


Part of me must ask: Do I suppose I bent the cross shaft slamming that taper pin with a hammer?

I'll try rolling it around and eyeballing it.

 

[TR3driver]

IMO it's not likely you bent the shaft; nor particularly critical if you did.

I am surprised the remains of the pin wouldn't come out, through. Did you make sure to have the fork in the right position relative to the shaft? (Meaning you could look down the hole and see the broken pin.)

 

[KVH]

Unfortunately, I cut my shaft "in two" and removed it and the fork just moments ago. What a nice piece of solid steel that was. What a shame and waste of time. I had carefully cut that fork off, taking about 90 minutes of careful cutting.

But after getting fork off that pin was impossible, and I could see that the wear on the shaft was unacceptable. As for the pin, it looked like someone had peened it to death. The top was flattened and distorted, almost welded to the hole in the shaft.

Just for kicks I put the shaft in a vice and tried driving the pin out with free swings of a five pound hammer. It wouldn't move the slightest bit.

I'll get new parts from TRF and Moss.

I'll also chase down that play in the input shaft of the transmission, but my guess is I'll be learning that rebuild next.

When I'm done, there will be precious few mechanical things I haven't done on a TR4. Though I will have removed and installed two differentials and swapped out sliding axles for CV axles on an IRS, I will never have rebuilt, myself, the inside of a differential. That's not even something that sounds interesting. Especially that part in the manual about stretching the outside case. Then, I suppose I won't have rebuilt a transmission cover, though I'm still tempted there!

Beyond those things, I think I've got mechanical items all covered.

Thanks for all the help. I'll be back.

PS Randall, whoever installed the fork years ago, did install one with a pre-drilled hole aimed at the pin. But you are right; that hole is really off center a bit. I can't explain why it was already butchered and beat up in there, but it was. A complete mess.

 

[TR3driver]

Especially that part in the manual about stretching the outside case.

Turns out that really isn't necessary