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TR4/4A TR4 Front Suspension Rebuild

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M

mylesw

Jedi Hopeful
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Hello

I have now got my TR4 frame back from the frame shop so I can finally start to rebuild the car. Being eager I have built put the wishbones, trunnions, vertical links etc on both sides. Took a while and was done more than once, however...on the side where I have kept the old trunnion, the stub axle can be moved from side to side with very little force (pinky) but the side where I had to install a new trunnion it needs a lot more force to move it (good shove). Now my question...does this matter? Should I disassemble my handiwork ot will this new trunnion bed down and turn more freely as time progresses? Thanks for your help...

Myles
 
Myles,
I just did the front end rebuild of my 3 and they are very similar except that you have some castor built into your units.
Assuming you've already greased the trunnion and the upper ball joint assembly it shouldn't be that difficult to move (as described) but will most likely be tighter than the older unit.
Mine moved freely with little force so something is binding.
If I remember correctly I backed the trunnion off one full turn from tight/binding with the rubber seal in place and it moved freely with no slop.
Is the assembly resting on the lower rubber stop? The angle is important.
 
Herman van den Akker once reported finding a whole bunch of bent vertical links, which caused the same problem. Moved freely with old, worn trunnions, but were tight with new ones.

IMO, yes, you should fix it. Try pulling the upper ball joint, and watch what happens as you rotate the vertical link. If the hole for the BJ appears to move in a circle, the link is bent.
 
Myles-

If you get into a pinch on parts, pm me. I'm close enough to you I think and I have a couple of spare vertical links squirreled away if you find you have a problem.

I have spares now as my last vertical link was so bent it wouldn't thread all the way onto a new trunnion, but it fit nicely in the old one.

Regards,
Randy
 
When I had a problem where the front end of my TR3A was hard to turn (while up on jack stands and the front wheels off), I contacted Herman who had previously talked about this condition. The threaded end where the top ball joint is bolted into the upper "A" frame (upper wishbone) had rotated slightly as I was tightening up the big nut on the back and this was causing the stiff steering. The so-called "splines" that centralize this were a bit off on the new ball joints, so I pre-set them the other way and when I tightened up the big nut on the top inner side, the tightening cause it to rotate to the correct position and it came out perfectly aligned. It's been fine since.
 
So, got the tunnion and vertical link off the car. Can't quite tell if it's bent or not. Sometimes I think it is, other times I think not. So I took off the other vertical link and tried to screw the offending link into the other trunnion. Went in better, but still some tight spots and quite stiff near the end. Funny thing is that it screws into the old trunnion perfectly. So I think the vertical link must be slightly bent, although if someone has a way of measuring it I'd be grateful. Also, can you straighten these or is a replacement the way to go?

Thanks for your help

Myles
 
Those threads are the only thing keeping the car off the ground ... I'd replace them.

And if they bind screwing into a new trunnion, I'd say that's pretty good evidence the threads are distorted/bent (although I supposed it might be a bad trunnion).

Never tried comparing with a thread gauge, but should work. The form will be all wrong, but you should be able to check the pitch that way.
 
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