TR2/3/3A TR3A front suspension rebuild

[Dr Evil]

This part is the right side trunnion, looks fine to me. as long as the spindle is the correct thread , you
lube it and install. Then you set the tr4a upper arms( in place of the tr3 bits) and install the tr4 upper BJ.
Now you have castor like a modern car does. Don't overthink this, the lower arms don't change, only
the angle of the spindle assy in relation to vertical. DO NOT try to install RT on the left side with the upper arms either
The Tr3 did not have a RT & LT but the Tr4 does.
Mad dog

Cameras distort angles. but if you look at the shoulder of the trunnion, it is not vertical, it leans backwards 3 degrees with the trunnion itself. this means the a-arm and thrust washer which is vertical will not sit flush against the trunnion.

 

[mctriumph]

I don't see this but if so it would suck a LOT!!! I say that a good test fit will tell all.
Mad dog

 

[CJD]

If you don't have a lathe, check with your supplier, as that is not correct. It will throw off your clearance in setting the lower A-arms. Even if you get the clearance correct, it will open up quickly as it will be riding on a point instead of an entire face.

 

[TR-3rg]

Hi,

I have made this same conversion on my TR-3a. The trunnion is machined wrong. When correct, the shaft and the machined faces on the trunnion, are at right angles to each other. The spindle and casting, are offset 3 degrees. When assembled, there is no gap between the trunnion and the control arm. I looked at my set up and I don't think its even the correct casting. I would send them back for correct parts or a refund.

Good luck,
Roy

 

[mctriumph]

It always pays to inspect AM parts closely, never "assume" it is any good
Mad dog

 

[Jim_Stevens]

It was the first thing I did as well on mine. As a minimum, shift to polyurethane bushes over the rubber. Also I recommend looking at RevingtonTR for any new components. They offer different levels of upgrades which might interest you. Welcome to the hobby!

 

[Dr Evil]

The first photo shows the problem more clearly; the shoulders are not adapted to the 3 deg caster; suspect it is just a 0 deg casting that has been bored at 3 deg. The supplier agreed to take the trunnions back, but they said they had sold many and never had any complaints. I'm not sure the service guy understood what I was talking about...

I ordered a set of 3deg trunnions from Moss, 2nd photo you can see they fit flush with the a-arms.

Anyway, they are on with the new tophats/thrustwashers and seals. I had to abandon my adapters for adding negative camber, couldn't get the fitment right, so installed the stock fulcrum setup with TR6 a-arms. so far so good.

 

[mctriumph]

Camber is achieved by slotting the upper arms to move the BJ inboard. Then you must fab an
elliptical washer drilled to match the BJ bolts. Install with #8 bolts and Loctite the plate so it bonds to the
arm when torqued at the desired angle. You can only get 1.5 deg this way but it beats nut&honey.
Mad dog