TR2/3/3A Re-tapping a zerk in a brass trunnion housing?

[GTP1960]

Found that the drivers side, trunnion grease zerk Is missing, the threaded hole in the base of the trunnion is distorted and the brass cover is slightly distorted also. ( impact damage)

Any suggestions on repair options?

thanks and best regards

Guy

 

[TR3driver]

Hardly seems worth the effort. Trunnions are consumables, so I would just replace it.

However, you could take it apart and use a drift to more or less push the end cap back into shape, then run a thread repair tool into the threads. 1/4-28 IIRC.
If that won't work, use a Helicoil.

 

[titanic]

Probably, someone tried to use the trunnion as a jacking point. If the trunnion doesn't appear to worn, I would try to retap the hole (1/4"-28?) or go to an oversize fitting, possibly 1/8" pipe. Also, I was less than impressed with the quality of a repro trunnion purchased for use on a TR6. The fit was looser than the worn original.
Berry

 

[GTP1960]

Hardly seems worth the effort. Trunnions are consumables, so I would just replace it.

I haven't done this before.
Some questions on trunnions:

how can you tell if they are worn out?

should you replace both sides at the same time, for balanced wear?
what other consumable should I replace while I'm in there?
Does the trunnion cross pin (bolt) slide thru the wishbone or will I need to remove the lower wishbone arms.
(& anything else?)

I can't find removal technique in my workshop manual.

thanks.

 

[GTP1960]

I was less than impressed with the quality of a repro trunnion purchased for use on a TR6. The fit was looser than the worn original.

do you recall where that repro came from?

since trunnions wear out anyway, what about having a zerk welded in?

or if my trunnion proves ok.
i may just use a rubber plug until I do replace the whole trunnion.

 

[titanic]

do you recall where that repro came from?

since trunnions wear out anyway, what about having a zerk welded in?

or if my trunnion proves ok.
i may just use a rubber plug until I do replace the whole trunnion.

The trunnions came from BPNW. I didn't return them and just used the originals. They are slightly different from the ones used on TR3s.
The trunnion pins used on TR3s are splined (to prevent rotation) and are a light drive fit in the trunnion. I think it is necessary to compress the spring to remove the spring pan and remove the lower wishbones in order to remove the trunnion. Others may differ as I am going memory, as I sold my TR3 some years ago.
You should be able to judge the amount of wear in the trunnion by tightening the wheel bearings to remove all play, then grab the wheel and the top&bottom and moving it. There should be very little movement.
If it were me, I would try to find a way to install a grease fitting(not weld) on the present trunnion (unless it is grossly worn) until it is time to disassemble and overhaul the front suspension.
Berry

 

[TR3driver]

You have to remove almost the entire suspension to get the trunnions out, but it goes fairly quickly. I've done both sides in an afternoon without hurrying. Look for the manual section on removing the suspension unit. You can leave the upper arms & ball joint attached if you want, and the stub axle can remain in the vertical link. But you'll have to compress and remove the spring (using the special tool or equivalent), spring pan & lower arms.
In my experience, most of the wear is in the pins and the bushings that ride on them, so you should.probably plan on replacing the bushings as well. Which means reaming them to size after installation.

OK, so it's more work than I was thinking about

 

[GTP1960]

If it were me, I would try to find a way to install a grease fitting(not weld) on the present trunnion (unless it is grossly worn) until it is time to disassemble and overhaul the front suspension.
Berry

hey thanks guys,

the trunnions (and front suspension) all appear in good shape.
I'm going to see about having a brass nut (of correct size ) brazed over the distorted hole.
then I can just screw the correct zerk ( might need to convert to a 45degree) in & it's almost like business as usual.

question is can I find a welder with the skill to work that close to the disc brake.

also I inserted grease & a rubber plug & took it for a test drive.
Plug remained, so I'm pretty sure I can make it to a shop without AAA.

not up for suspension 101 this week!

thanks again

 

[TR3driver]

There's a bunch of grease inside the trunnion casting. You might want to consider what happens when it gets heated that hot.

And whether you want to leave the ashes inside the joints.

 

[GTP1960]

There's a bunch of grease inside the trunnion casting. You might want to consider what happens when it gets heated that hot.

And whether you want to leave the ashes inside the joints.

might be back to removing the trunnion.
the angle toward the disc brake is pretty tight.
Dont know if a standard length tap could fit


if I have it welded, couldn't I flush it out with brake cleaner to remove the grease etc. before I have it welded?
what's the function of the bottom cylinder of the trunnion, anyway?


thx for pointing that out.

 

[martx-5]

...
what's the function of the bottom cylinder of the trunnion, anyway? ...

The trunnion is the pivoting point for the steering. The bottom of the vertical link is male threaded (like an Acme thread) that screws into the the female threads of the trunnion. The threading provides turning capability and a positive connection between the vertical link and trunnion.

 

[Got_All_4]

If your set on doing the nut thing and don't want to remove the trunnion (it's crazy not to) then use a lot of brake cleaner with a straw shoot it inside and have the front end jacked up and have someone turn the steering wheel left to right while your spraying. Also instead of brazing and dealing with all that heat why not solder a nut on yourself. Very easy and you wont destroy everything around the trunnion with all that heat. Remember it travels.

 

[GTP1960]

Probably, someone tried to use the trunnion as a jacking point. If the trunnion doesn't appear to worn, I would try to retap the hole (1/4"-28?) or go to an oversize fitting, possibly 1/8" pipe. Also, I was less than impressed with the quality of a repro trunnion purchased for use on a TR6. The fit was looser than the worn original.
Berry

Berry, you nailed it ( pretty close) I found the old zerk in the corner of garage. I surmise the trunnion was damaged when I had a Jacking accident the other day. I think the zerk was knocked off when the car shifted on the stands.
also I was trying to make a mountain out of a mole hill. Simply had to flatten the distorted end of the trunnion with a 3 lb. persuader & retap with a 1/8-27 Pipe thread tap. The old zerk went right back home and seems to work fine.

thanks everyone, for the input

 

[2liter4cyl]

Glad you had success. FYI, there are 2 kinds of zerks. Where I worked, we sold both screw-in and drive-in. To me driving one in would be better than welding. Le

 

[titanic]

I am glad the story had a happy ending with a minimum of effort and didn't involve a torch.
Berry

 

[GTP1960]

Glad you had success. FYI, there are 2 kinds of zerks. Where I worked, we sold both screw-in and drive-in. To me driving one in would be better than welding. Le

I agree Le,
I'm lucky Larry, Randall & Berry, gently steered me down the better path.
welding a nut on was unnecessary & unwise.

took it out for an hours test drive, after greasing all the zerks & it felt fine.

 

[KVH]

You have to remove almost the entire suspension to get the trunnions out, but it goes fairly quickly. I've done both sides in an afternoon without hurrying.

I have a Moss spring compressor, the long threaded rod. It's worked for 12 years, but each time I use it I hear a sudden creak and pop like it's slipping across a thread or two. Is that what's going on? Is there a better tool?

 

[TR3driver]

Might be the bottom plate slipping over a thread; but certainly not the nut slipping. If it had slipped even once, the damage would be obvious and it wouldn't work any more. Some grease might help.

Here's a shot of my home-made version, which is quite a bit beefier (3/4" threaded rod)


And a shot of it at work