TR2/3/3A Rear spring front pin removal

[TR3driver]

Randall,whats the deal with alum blocks?
Where different length shackles ever used?

Sorry, I missed that before. AFAIK the shackles were always the same. Non-IRS TR4A uses a different shackle than TR2-4, but still the same on both sides.

Not certain of the theory, but the higher arch (camber) springs were supposed to be an improvement in handling. The spacer blocks allow the positive camber springs to be used. Unfortunately, I'm told they don't fit a TR3. Apparently the frame changed at the same time.

 

[TFB]

Thanks again for replies.
So whats involved to install shims?I see a bolt sticking thru the bottom shock link plate,assuming it holds diff. mount plate in position.
Can I just support frame,unbolt u-bolts and jack up rear to remove bolt and add shims,or does rear shackle have to be disconnected?
Or,can I use a slotted shim and just loosen the center spring bolt and slide in shims?
Thanks again
Tom

 

[Geo Hahn]

...So whats involved to install shims?I see a bolt sticking thru the bottom shock link plate,assuming it holds diff. mount plate in position.Can I just support frame,unbolt u-bolts and jack up rear to remove bolt and add shims,or does rear shackle have to be disconnected?

Here's a shot of the spacers in place (not mine) that may help you visualize:

...Or,can I use a slotted shim...

That's what I did on my TR4. It did not come with spacers but I was able to add 3 made from 2" x 1/8" aluminum stock. I loosened the nuts on the U-bolts and got enough space at (2) to slip them in.

I was limited by the amount of U-bolt I had to work with (1) and when done replaced those Nylocs with some all-metal locking nuts that were a bit thinner.

The shims were slotted (lengthwise) to just slip in around the center bolt and the direction of the slot alternated with each 'layer'.

All told I got 3/8" of adjustment which is what I needed. 2 years on I see no movement or problem with this set-up.

Only you can decide if this is a real fix or a bodge.

Note: that is a TR4 spring shown in pic #2 -- has a different arc and a big aluminum block to accommodate that arc.

 

[TFB]

Here's a shot of the spacers in place (not mine) that may help you visualize:

That's what I did on my TR4. It did not come with spacers but I was able to add 3 made from 2" x 1/8" aluminum stock. I loosened the nuts on the U-bolts and got enough space at (2) to slip them in.

I was limited by the amount of U-bolt I had to work with (1) and when done replaced those Nylocs with some all-metal locking nuts that were a bit thinner.

The shims were slotted (lengthwise) to just slip in around the center bolt and the direction of the slot alternated with each 'layer'.

All told I got 3/8" of adjustment which is what I needed. 2 years on I see no movement or problem with this set-up.

Only you can decide if this is a real fix or a bodge.

Note: that is a TR4 spring shown in pic #2 -- has a different arc and a big aluminum block to accommodate that arc.

Thanks Geo.Looking at diagrams and the car,I was thinking the differential mount was bolted to top of spring,but now I see that its part of the rear housing.
So,The shim can be put in without removing bolt?
Guess it will be obvious when I disassemble.
Thanks
Tom

 

[CJD]

I thought the shimwas held BY the bolt. Are we talking about a different shim?

 

[TR3driver]

FWIW, the center bolt through the spring is what provides positive fore/aft location for the rear axle. Even with the factory shims, the head of the center bolt engages with a hole in the bracket that is welded to the axle. If you add flat shims just notched to fit around the bolt, you lose the positive location, leaving the axle located only by friction. Which certainly might not ever be a problem, especially if you never drive the car hard. But personally, I would want to go the extra distance. I do drive hard on occasion, and leaf springs aren't all that good at locating the axle to begin with. (I might even try adding a Watts link some day.)

One route would be to fabricate a shim that transfers the locating feature (by having a hole to engage the bolt head, and a spigot to engage the axle). All commercial "lift" blocks that I have seen are designed this way. Eg,
https://static.summitracing.com/global/images/prod/xlarge/EXP-65225K_xl.jpg

Another route of course is the way the factory did it, with the center bolt going through the shims as well as the spring. I think this probably could be done on the car, but you would of course have to take the U-bolts loose and move the axle enough to get it out of the way. You'll also need a big C-clamp to compress the spring leaves when inserting the center bolt. And if you are going more than the factory shim thickness, you'll need a longer round-head bolt.

PS, by factory "shims", I don't mean the big aluminum blocks used on the later high-camber springs. They used the first locating method, like the blocks from Summit.

 

[TFB]

Thanks Randall for the detailed info.I will probably drive the car for awhile the way it is,and prep for new springs.
Thanks again
Tom

 

[Geo Hahn]

FWIW, the center bolt through the spring is what provides positive fore/aft location for the rear axle.... personally, I would want to go the extra distance...

Thanks for the insight. Though noting has moved in the years since I did this, I have since acquired (from when I replaced my TR3A springs) a set of the original shims. If I can get suitable (longer) U-bolts I will go with those and a longer center bolt.

 

[TFB]

Thanks for the insight. Though noting has moved in the years since I did this, I have since acquired (from when I replaced my TR3A springs) a set of the original shims. If I can get suitable (longer) U-bolts I will go with those and a longer center bolt.

Yes,thanks for all this info.I have a much better picture of whats required and will most likely do what I was thinking of first and replace springs,then maybe shim if required.
Thanks again,
Tom