TR2/3/3A aftermarket trunnions?

[sp53]

I have heard from eBay sellers on eBay (for what that is worth) that the Trunnions manufactured today are of poor quality, but what to do make my own? Has anyone had trouble with the aftermarket trunnions? I do have an old set that I turned smooth again, but they would be a little too small for the bushings. My experience has been that TRF stuff is more like OEM, so if I did go new, I would most likely buy there, but again if there is only one vender manufacturing them, I think I will go with the best deal.

 

[TR3driver]

The last pair I got from Moss (which was a very long time ago now) leaked at the bottom so they couldn't be greased properly. I was able to repair the leak to some extent, but couldn't stop it entirely.

The ones I've gotten more recently from TRF do not leak, seem to fit perfectly, and have lasted a long time. The ones on the wrecked TR3A probably had 50 or 60 thousand miles on them, and were good enough that I considered reusing them on the current TR3. I didn't, mostly on the fear that there might be hidden damage from the accident (even though I did keep most of the other components).

Of course, the lifetime depends a great deal on how often you lube those joints. Most people (including myself) are not willing to grease them every 1000 miles as the book calls for. My grandfather would be upset, I can remember a stern lecture about always following the maintenance schedule both for time period and number of strokes. "You give that steering swivel 3 strokes every day, you hear?" Fortunately, he isn't around to see

 

[sp53]

I will most likely buy new, but it seems to me that the path of the trunnion travels is dominantly on the top ¼ and never goes around. The weight of the car must sit right there, so if there is a little slop it would be at the bottom and perhaps a small amount of play would sit at the bottom and do no harm, but again I guess when I hit something on the road the force would go up. Again it is one of those deals like the rocker bushing where the bushing seems to wear less than the hard steel.

 

[CJD]

I had a difficult time getting a set of trunnions from Moss that worked about 3 years ago. The batch they got had loose tolerance for the vertical link screw, so they had more slop than the ones I was replacing. I sent back 2 sets...the 3rd finally felt tight. But, they did have the grease leaking issue Ranbdall talks about. I tried my best to get the disc to seal...but gave up. I have to pump as fast as I can to get the grease into the trunnion as well as running out the bottom disc.

TRF was back ordered when I went through this. I would hope the latest trunnions have fixed the clearance issues...and leaking bottom discs.

 

[TR3driver]

I will most likely buy new, but it seems to me that the path of the trunnion travels is dominantly on the top ¼ and never goes around. The weight of the car must sit right there, so if there is a little slop it would be at the bottom and perhaps a small amount of play would sit at the bottom and do no harm, but again I guess when I hit something on the road the force would go up. Again it is one of those deals like the rocker bushing where the bushing seems to wear less than the hard steel.

That's actually a common problem when the wear is caused by abrasive dirt in the joint. The particles embed themselves into the softer side, and then abrade the harder surface. (Kind of the way a diamond hone works, with specks of diamond embedded in a soft metal.) However, I've usually found that the bushes in the A-arms were pretty badly worn as well.

Definitely, all the load is on one side, the other side doesn't wear at all. If you think about it, the entire weight of that corner is resting on those two trunnions, and the arm only rotates by a few degrees. The only time the other side of the pin comes into play at all is when the suspension is at full droop against the stop (and you've gone airborne). And even then, it only carries the weight of the wheel, vertical link and brake caliper.

Many years ago, I "made do" by having the trunnion pins ground back to nearly round and installing new bushings without reaming them. It worked out well enough; but not something I would recommend to others. The machinist said the pins were too hard to cut in the lathe, they had to be ground. But I wasn't there when he did the work, it was a "friend of a friend" deal.

Another concern is wear in the threads inside the casting. Kind of hard to assess accurately, but those threads are also carrying the entire weight of the car. If they break, the results will not be pleasant.

 

[TRTEL]

When you do eventually find a good fitting pair, a recommendation I would toss in is to use ARP's moly disulfide lubricant when assembling. It usually is provided in a squeeze packet and I believe can be purchased separately. But it is the additive to have in there to begin with both on the link threads and bushes. The ARP mix has the highest moly content i'm aware of. If you should opt to have them concentrically ground down as suggested by Randall have them make it the tightest clearance they think is reasonable, again for all the design reasons mentioned by Randall. The guy I worked for preferred to use the original bushings and would press on hardened sleeves, which I believe he bought from an aircraft supply. I think he also used to add some epoxy glue in the process.

 

[sp53]

That sounds interesting and should work. I was thinking that all I really need is the shaft. The shaft comes out without too much force and is splined in place. If one of the manufactures would sell me the shafts, I would be happy, or if I was a machinist, and had the equipment I would try it. Many years ago I worked for an outfit that had that knurling stuff. The shaft is not that hard; I took some metal off on a drill press with emery cloth.