1976 T/C Rod, Broke, Polyurethane Bushings

[Zed Head]

Here is a picture of one more Z car T/C rod gone. I installed MSA polyurethane bushings front and back on the T/C rods of my stock 1976 280Z about 4 months ago and have put about 3,000 fairly easy road miles on since then. I had read the various accounts of broken rods but the evidence still seemed iffy and most of the descriptions seemed to be for the later model cars with front-oriented T/C rods and not the rear-oriented Z cars. So I decided I would do both sides with polyurethane on my car and see what happened.

It looks like fatigue cracking started top and bottom and just worked its way through the bar. The coup de grace may have been when I backed the front wheel in to the curb while parallel parking. About ten miles later, that evening, I heard something bumping off the bottom of the car, but had not seen anything in the road. So I took a look under the hood in the morning and saw that the rod end on the passenger side was almost worked out of the bushings, the rod was broken at the base of the turned-down end, and the big washer on the inside was gone. That was the noise.

I had a spare rod from a 78 and used the rubber bushings on the back on both sides, in place of the hard polyurethane, as described around the various forums, to take some of the bending pressure off the rod end.

For the record, for those still wondering.

Edited March 8, 2010 by Zed Head
Added a picture.

[ktm]

Here is a picture of one more Z car T/C rod gone. I installed MSA polyurethane bushings front and back on the T/C rods of my stock 1976 280Z about 4 months ago and have put about 3,000 fairly easy road miles on since then. I had read the various accounts of broken rods but the evidence still seemed iffy and most of the descriptions seemed to be for the later model cars with front-oriented T/C rods and not the rear-oriented Z cars. So I decided I would do both sides with polyurethane on my car and see what happened.

Sorry to hear that you broke a T/C rod, but when I read the title I instantly knew I was going to read about poly bushings.

The evidence is not "iffy", you just ignored the evidence to, as you said, "see what happened". You even knew the remedy. I do not mean to come across as an arse, but really, at least be honest with yourself and others.

The evidence was enough for me to not install the poly bushing in the rear of the T/C rod.

[Zed Head]

Changed mind on comment...

Edited March 8, 2010 by Zed Head

[vercingetorix]

I broke two in a row and when I was replacing it myself instead of having a mechanic do it I found my transverse link bushings were completely shot,replaced them with urethane as well and no trouble since. Thats been several years now.

My2c

H Houghton

[Zed Head]

Good point, thanks for adding.

I did notice that my control arm bushings were worn also, with visible cracking, and thought that it may have contributed. Before I took the broken T/C rod off I found that I could grab it like a handle and move the control arm around easily, with play visible in the control arm bushing. The end of the broken rod actually hung about an inch below the bushing mounts because of the worn control arm bushings, so there was probably a side load on the rod also when in use.

I didn't want to do the control arm bushings yet so just went with the rubber in the back for a short-term fix.

Has anyone replaced the bushings with the arm still in the car? I enjoy laying under my car so might try it...:classic:

[sblake01]

When I bought my 78 back in 1997 I put urethane bushings on the transverse links as well as on the T/C rods. Drove it like that for the next 12 years or so until I sold it with no problems.

[jmortensen]

When I bought my 78 back in 1997 I put urethane bushings on the transverse links as well as on the T/C rods. Drove it like that for the next 12 years or so until I sold it with no problems.

Lots of people use poly on both sides and never have an issue, use of poly on both sides does not guarantee failure. Putting rubber on the backside still gives all of the advantages of poly on both sides (the bushing only gets loaded heavily under braking and heavy bumps, and only the front bushing takes the load) so it is a win/win to do poly front and rubber rear. It doesn't cost any more because you can use the worn rubber part in the rear with no detriment.

[Zed Head]

Thanks all for the comments. I feel comfortable now with poly front/rubber back, although the steering does feel looser. Replacing the LCA bushings will probably help that, I'm sure.

ktm, I'm just telling a little story here, and trying to add to the body of Z Car knowledge, with some pictures and solid facts, for anyone to use as they choose. That's all. No intent to offend or ignore anyone else's hard work.

[Zed Head]

Good point, thanks for adding.

Has anyone replaced the bushings with the arm still in the car? I enjoy laying under my car so might try it...:classic:

Quoting myself above. Kind of nonsensical. Four small bolts plus one big one - I'll just take the LCA off...

[billyjarrell]

I'm with sblake01 on this one. I had the urathane bushings front and rear on my car for 4 years, and over 18,000 miles with no issues.. That includes 3 autocrosses with them. I did install the entire urathane kit at the same time so maybe there is something to having the control arm bushings in good shape too. I just recently switched to the delrin/aluminum cup and ball setup from MSA on the front and kept the urathane bushing on the rear. One modification though, I took the center metal sleeve out of the rear bushing so that the T/C rod can have full movement up and down allowing the cup and ball socket to move while still preventing any rearward movement.

[gnosez]

I solved this issue by going with the TechnoToy Tuning TC rod after replacing the nylon piece in the aluminum set-up every year.

Easier to get more caster with it as well.

[Zed Head]

To tie it up - I replaced the transverse link bushings with polyurethane, and left rubber bushings in the back on my T/C rods (for the reasons jmortensen proposed) and kept the urethane in front. The steering is now much tighter and the wheels don't shift when I hit the brakes, like they did before. So I came out ahead, overall, after the motivation of the broken T/C rod.

FWIW, even with the old rubber bushings off, it is hard to tell that they are bad. You can stick a big screw driver in the center, brace it and reef on it to get them to move, but it's not obvious. The cracks in the rubber are only visible when it's stressed.

By the way, a Truecraft 27mm 3/8 drive socket, part #45227 (manufactured in the early 80s, may be different now) is a "too perfect" fit for pressing out the complete bushings from the transverse links. Too perfect because it takes as much force to press the socket back out as in, but it's easy to fixture the socket with a bolt or rod to press it back out since it is solid and you can press on the center. But it fits the outer bushing ring perfectly.

Thanks for all of the input.

Edited March 11, 2010 by Zed Head