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TR2/3/3A Rack & Pinion warning on TR3s--

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Jerry

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I was checking my alignment after putting on about 100miles on my car. I did put the MOSS R&P conversion on the car. While doing the measurements, i noted that the alignment changes as the wheel goes up and down. That is a sign of Bump Steer and the steering arm and spring platform are not parallel. Since the rack cannot be moved down, I will have to change the Rod Ends and use a bump steer kit to raise the steering ends of the R&P. I did try adjusting with a 3/16 washer, but it was not enough and there was not enough threads on the Rod ends to move them any farther. I have left a message for MOSS technical advisement but they have not called back yet.
So you may ask, what does bump steer do to the car? The front of the car may feel like it wants to jump around a little as one of the wheels either drops or goes up not in conjunction with the other wheel. i could feel it when I was driving and decided to fix the issue. Since this is not a race car, it may not be a dangerous issue but it will put stress on the steering and suspension. Also, more wear on the tires.
I should have this fixed by next week and I will report back with the parts and if I can tell the difference while driving.
Jerry
TR3a
 
And they thought they were going to slip one by on you! I'll be curious to hear what they come up with.
 
Just wanted to give you some feedback on this issue. I put the car on the rack and when the wheels were on the ground, the alignment was neutral, IE: the tires were pointed straight. At full extension, the wheels went to a toe out of 3/4 of an inch. You could really notice this while driving. I bought a kit from the link below which matches the 1/2 NFT steering rack threads. It is on the market to be used on a Pinto. It just happens to match up with the steering rack sold by MOSS. The kit comes with new rod ends , two bolts and various spacers. After much experimenting, and thinking about physics, we figured out we need 1.125 of spacer to make the steering rack parallel with the spring pan. Measurements on the alignment now is aligned on the ground but full extension is only 1/8 out of alignment. This is acceptable since I don't plan on jumping or racing the car. The car went for a test drive and what a difference! This steering rack also has an adjuster nut just like the original steering box and this should be check to see how much play is in the steering system. IE: Turn the wheel and see if the tires move, if not tighten the nut some till you have no gap in response.
Last step is replacing the lock nut sent with the kit to keep the rod ends in place. That nut is tighten up during each test and it took about 20 changes to find the correct setting, a lock nut is not made to keep functioning with that much use, so I replace them with a new nut.

Jerry
TR3A
austin mini 68
Austin Healey 67



https://www.racecraft.com/index.php...id=165&zenid=b9cafbb10be845f0eca5277bba3ea3b7
 
Jerry, I think that's pretty cool that you came up with that . What did Moss have to say ? I would think they'd be glad to hear of it.
 
MOSS never called me back. I left a message on their tech line about the issue. I had previously talked to them when I first installed the kit. At that time, they indicated that they had no complaints from other customers. I have seen this before on a race car and knew that it would need fixing. I can't imagine that other people that change steering from original, would not see some issue also.
Jerry
 
I agree but they not be as tuned in as you are to how the car should steer with it right. I guess I wouldn't doubt that you are the first to notice. How does a TR4 look with regards to this geometry?
 
I helped my friend rebuild his early TR4 and the steering looks similar to the TR3 with a rack but since it was designed for that rack, I did not notice any problem with his. Next time you plan on jacking up your car, measure the front of the tire, middle grove to middle grove, and then do the same thing after the wheels are off the ground. That will tell you if there is an issue. Also, a good test for all of us on these old cars is to wiggle the steering wheel and watch the front wheel. Does it move or is there a gap of no movement? Then look to adjust the nut on top of the box.
I used to have another TR3A and that one kept the original steering. My wife and daughter thought it was a bit tough to turn. So on this car we went for the upgrade and I like it! It just needed some adjustments. Pat Galvin put in a R&P also, but it was from a different manufacturer so we will wait to see his on the road to see if there are any issues. He just lives down the road so we can fix it if it needs any changes.

Jerry
 
I have rebuilt the TR3's steering box and the remainder of the steering components so I should be fine for awhile . I do like a rack and pinion steering system however.
 
I bought the Bastuck R&P kit (allows you to keep the stock horn ring functional). It was expensive and I'm hopeful that it is well designed. When on the road, I'll first see how she feels before I let Jerry tell me how satisfied I should be. Hah!

Thanks for the helpful post Jerry. I didn't really understand bump steer until you explained it here.

pat
 
My understanding is when converting to R&P the front suspension needs changing to TR4 trunions and upper A arms to gain positive castor. Is that correct?
 
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