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TR4/4A TR4 Laygear circlip - or lack thereof

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AHS

AHS

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Hi, I've got a question about a TR4 transmission rebuild. I've never done a TR transmission before and this specific one is CT33xxx. Most of it was in good shape but there was some wear on the layshaft at the rear bearing, which I understand is common. The rear needle bearing also needs replaced. The odd think is that the bearing housing was not pressed fully into the layshaft. It was flush with the end of the layshaft but there was about 1/8" gap at the inside end of the bearing. The drawings I have show a spacer washer beneath the bearing and a circlip on top, and this bearing appeared to have neither. Missing components would explain the extra gap. The bearing housing was pressed in place and wasn't going anywhere, in fact it had to but cut out. The bearing was a made in UK Torrington bearing, and I think it was original. Now that the bearing is out there is not even a groove for a circlip. Is this normal?

Now here's the odd part. The front bearing clearly has a circlip and is slightly below flush. There is no gap at the bottom. I don't want to remove the front bearing because I think it is OK, so I don't know if there is a circlip groove. It seems very odd that the front bearing is not retained in the same manner as the rear.

One more thing - I got a new layshaft but it is .002" smaller diameter than the original. This is enough that there is just a little rattle in the bearing. Have others experienced this? I suppose I'm stuck with this, as the old shaft has some damage.

I'll order a new bearing, spacer & circlip, and I hope it is a press fit like the old one. I don't think I'll be able to use the circlip as there is no groove. Am I assembling this correctly or am I missing something?

Thanks,
Andy
 
The gap behind the bearing is really important. Its where you put the puller jaws to get the bearing out.
They are a pain if somone has pushed it right in. I had to make a special tool to get one out.

Can't remember there being any circlips. But there are two distinct bearing types. One, the older one has rollers that can fall out.
The later ones have roller that dont fall out. I have an idea they inter-change.

You will need some kind of tapered guide tool to get the layshaft back through without barking into the corner of the rollers and winding up with a disaster. The layshaft pushes the taper through in front of it and this opens out the rollers and the shaft slide in behind the taper.

I turned a nylon plug but you could carve it in wood I expect.
 
Andy,

There shouldn't be a circlip retaining the layshaft bearings in the countershaft gear/hub or a spacer. The original ones were a press fit and should be flush (the factory manual shows a stepped drift for installing them - "lettered face outwards") although at some point they did switch to the open-cage ones (certainly by the time of the TR6). I would definitely replace both the front and rear since they are a failure point although I think the rear one is the one that usually fails. You don't want to have to do this again anytime soon for a $20.00 part!

The factory manual shows the countershaft diameter to be 0.8120" to 0.8125". If yours doesn't match that, I would send it back to the vendor as defective. The bore of the countershaft gear for the needle bearings is shown as 1.062" to 1.062".

Scott
 
The next question is "how do I get the bearings out".

Somewhere I have a photo of the original Sykes puller for this job. Shout if you are interested.

I invented a puller to do this. It has two tiny conical "jaws" and a threaded rod to open them and pull on them.
Easy if you can get on a lathe.

These bearings are not very tight. But they wont jump out at you either.

Guys have been known to succeed by Dremel and smash methods.
 
Thanks gentlemen. I don't have a TR4 shop manual as this transmission is intended for a TR3. The layshaft bearings are not the same. It sounds like the bearing is as it was pressed in from the factory, flush with the "Made in UK" facing outward. The front bearing appears to be pushed in too far as you said.

The new shaft measures .8100". The old shaft is .8123," within the specs Scott provided. I don't think I want to use it but I can at least wait to see the fit on the new bearings. Does anyone know of a source for good ones?

Alan, do you have a sketch of that removal tool? I do have a lathe. I cut the rear bearing out and the front is pressed too far in, so it may not do me any good, but I'm curious to see what you invented.

Thanks,
Andy
 
If you PM me I'll send the Churchill tool catalog.
Its too big to post on here.

See tool GV3.

I used a length of 3/8 all thread and two conical "jaws" like GV3.

You make a complete washer with the thread in it and slice in half.
Then grind bits off untll they drop into the bearing.

Fiddle about until you can screw the all thead in and force the jaws into th gap behind the bearing.

If you dont have a gap jack the jaws in behind the rollers.

Pull on the allthread with a nut and washer.

Nearly all the tricky TR dismantling can be solved by a homemade version of one of these tools.

If you have no workshop manual try this:

https://www.vitessesteve.co.uk/Servicemanuals.htm

Al.
 
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