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TR2/3/3A Trunnion bolts

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Frank Canale

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I am upgrading my front suspension to a tr4a front suspension. I ordered new lower trunnion bolts from TRF. My order arrived today and to my surprise I got to the trunnion bolts and checked the head of the bolt only to find that it is a metric bolt. I will give them credit they sourced a high quality bolt but first off, My car does not have metric bolts on it. Second the bolt is almost 1/8 ' short and is .003 undersize. Yes the bolt will work but for approximately $ 10.00 each I would expect the bolt to be right. My question, am I being too picky (Anal, yes I am when it comes to tolerances especially when it involves suspension) should I move on and pick another battle . If I do or don't send it back I will probably get with my bolt supplier and source the correct bolt. I can drill a hole for the cotter pin for a lot less than what these bolts cost. I thought the bolts were a special size or grade, not the case. This is not to bash TRF, I will be getting most of the new parts from them but this time a little disappointed . Frank
 
IMO someone made a mistake, you got shipped the wrong bolt. Since they are wrong, they tell you nothing about what you should have gotten.

Call up TRF, tell them what you found. I'm confident they will try to make it right (even though I suspect it was their supplier who made the mistake). Hopefully the others in the bin will be right and they can just ship you some correct replacements.
 
Frank what bolt is that exactly, do you mean the nylon nut( not original) that goes on each side of the spindle or the bolt in back for the lock.
steve
 
My mistake Frank, I did not know a tr4a used a bolt and not a spindle. I used tr3 stuff, but now I am in a panic after looking stuff up because I notice the tr4 trunnion has a 3 degree castor to it and on my tr3 it looks like the tire is not vertical and tips in at the top. Hopefully there is a way to check it before I put the fenders on, and if it is wrong TRF will hear about it big time.
 
TR3 wheels tip in as the bushings get old. With the suspension correctly set up they should be vertical to the eye. There is no adjustment for camber.
 
Send it back. There is a rash of bad parts being marketed by ALL of the vendors. I had to eat over $2k in bad parts during my restoration...an accumulation of parts over the 5 year restoration from all the vendors on both sides of the pond, and which I had too long to return. Don't tolerate the bad parts!
 
"Castor" means the steering axis tilts fore/aft; you can't see it at all just looking at the wheel.

If you had accidentally gotten the later TR4 trunnions, without using the matching upper A-arms, you would have had a lot of trouble getting the upper ball joint installed, and the VL would bind in the trunnion.

However, the front wheels on a TR3 should tip outward at the top very slightly (this is known as "camber") with the car sitting on the suspension. If yours tip in, it's worth trying to chase down the problem, IMO. You can start by making sure you didn't use the workshop manual procedure for adjusting the front wheel bearings :smile:

If you have a reasonably flat, smooth floor, you can get a pretty good measurement of camber using a carpenter's square, two 6" steel rulers, and a small C-clamp. Hold the square up with one leg on the floor, extending directly away from the car, and the other leg vertical at the center of the wheel. Clamp one ruler to the square, so the ruler is horizontal and just touches the wheel at the bead (not the flange that sticks out from the bead). Now hold the other ruler at the other bead and compare the readings. The upper bead should be 1/4" to 1/2" closer to the square than the lower bead.

If you want, you can turn the wheel 180 degrees and try again. Any change shows the wheel or hub is not running true.
 
Steve, the TR4 trunnions are right and left threaded to the vertical link. The bolt that I ordered bolts the trunion to the lower wishbone links. Frank
 
I think you mean TR4A trunnions, Frank. TR4 vertical links are the same on either side, meaning the threads into the trunnions are the same as well. The trunnions are only "handed" by which way the pin tilts for the 3 degrees of caster.
 
Thanks for your post Randall. I did mean camber. What is interesting is since I have lifted car up and down a bunch of times and aligned the front end. The wheels have improved and are vertical. Moreover, Randall thanks for the comment about the difficultly I would have had mixing up the parts. They must be correct. These 4 year restorations are painful at my age, but it is coming together.
 
I have resolved the trunnion bolt problem with the help of TRF. I made the mistake of only looking at the head of the bolt. This bolt has dual markings, the three slashes for grade 5 SAE bolt, it also has the metric 8.8 marking to indicate the tensile strength for metric bolts. I have never run into any hardware with dual markings so that was my first mistake. I also tried to thread the new nuts on the bolt and it would only catch the first thread and turn maybe a quarter turn. I called TRF and they pulled their bolt and nut and theirs threaded on no problem by hand. I figured I must be missing something, so I got out the thread pitch gauge and sure enough it was 18 threads per inch. I got out the adjustable 9/16-18 die and ran it loose on the bolt then adjusted the die a little tighter and that was enough to clear the excess plating on the threads. The bolt shank is at the minimum of manufacturing tolerance so it leaves me with a little more than .010 undersize of the trunnion bore. If I can find a bolt that is nearer the maximum tolerance it will put me at a nice slip fit. Any input as to bolt to trunnion fit is welcome. Frank
 
The only way to get the parts suppliers to improve their offerings is for us to let them know when there is a problem. If we continue to fix them ourselves they will not make changes to the parts. I have found that TRF is very good about that.
Some of the others not so good.

David



CJD said:
Send it back. There is a rash of bad parts being marketed by ALL of the vendors. I had to eat over $2k in bad parts during my restoration...an accumulation of parts over the 5 year restoration from all the vendors on both sides of the pond, and which I had too long to return. Don't tolerate the bad parts!
Click to expand...
 
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