Trunnions!

[ben711200]

I've always liked the word 'trunnion'. It's a lovely contraction of 'tri union' that rolls from the tongue nicely and reminds you of a bygone era where 'oiling your trunnions' was part of everyone's maintenance schedule.

And they made me fail my bloody MOT

Nearside trunnion front suspension has excessive play in a lower suspension joint

Nearside outer trunnion front suspension has excessive movement at a wishbone pin or bush.

From what I can fathom from the MOT man, I need to rebuild/replace the trunnions. Which is fine.. but then the internet suggests that maybe all I need is to redo the trunnion bushes. This would be nicer. MOT man also reckons that, in his distant memory, he remembers that the vertical link could be worn and so replacing the trunnions wouldn't do much anyway.

Is it a slag of a job to replace them? An overhaul kit is only £30 or so from Rimmer Brothers.. but to just replace the bushes sounds a much simpler job! Real life experience from Triumph people would be very much appreciated

[hairnet]

seth or the chap with the red h at RR are yer mates ;D

[ben711200]

Oct 13, 2009 20:41:33 GMT hairnet said:

seth or the chap with the red h at RR are yer mates ;D

Red herald? the rotary one? Is it Roy? I met him at the Gathering but am terrible with names. I'm hoping that Seth will spot and provide some info.. ;D

[gravelrash]

Trunnions are fun, usually fail on worn bushes ( top hat nylon, two stainless caps and a square section o ring x2) Not too bad to replace assuming the bolt isn't seized.
Said bolt could be loose and has elongated the bolthole in the wishbone (weld on a thick washer).
All said the trunnion could be worn, jack the car up remove the bolt and give it a waggle. Should be very little movement fore and aft.
To remove trunnion I think disk and hub off and wind it off ( one is lh thread). Have a look at vert link wear will be obvious at top of thread.

Ade

[beejay]

I did the ones on the Scimitar, Triumph setup but based on the TR I believe; I'm not up on my Triumph knowledge but assume it's similar to the Herald?
Took a couple of hours each side.
Replacing just the bushes would be easier if it comes apart nicely. The bolt can corrode to the trunnion, as happened to me, which could cause issues if you want to save the trunnion. I just ground the head of the bolt off, split the wishbone and chucked the trunnion/bolt mess in the bin
I still have slight play between trunnion and vertical link, suggesting the threads in the link have worn. Be interested to know if the Triumph guys have any work arounds to that or is it new vertical link time?
(Apologies for the slight hijack!)

[Seth]

Did someone call ;D

Impossible to tell without actually waggling things (as the MOT man does) where the play is. The bush kit is cheap enough that you might as well replace them as you've got to take them apart anyway. In fact the last time I bought new trunnions they came with the bushes so check that if you do end up ordering them. Get new bolts too.

I have more often expereinced wear to the wishbone holes rather than anything else. It looks like this.



As gravelrash said a quick fix for this is to weld on a thick washer. I went a bit further on our car last year, welded up the ovality, made proper thick washers, welded them on and reamed them to bang on the right size for the bolt. Needed slightly longer bolts too as I ended up tripling the original thickness.



If the play is actually in the threaded section of the trunnion you may get away with just new trunnions rather than needing the whole vertical link. Again, as gravelrash says you need to take the hub/disc and backplate off to unwind the trunnion from the vert link. (You won't need to take that lot apart if you're just replacing the bushes.)

Be warned with new trunnions that their quality is variable. They can have badly fitted blanking plates in the bottom that let all the oil leak out. Fix for that is to soft solder the from the outside to seal any gaps.

I would suggest buying parts from Bill at Rarebits as you'll get the advantage of the wealth of knowledge he has and he doesn't sell duff parts (or if he does he'll tell you they're duff first!)

[ben711200]

thank you very much to everyone! I'll get it up on a jack tomorrow evening and give it a wiggle and an investigative strip down...

[ben711200]

I've done the job.. And all went well. But....

I still appear to have play when I grab one of the wheels either side and wiggle.. My dad reckons it's somewhere in the steering.. I don't'. But I'll humour him and isolate the suspension from the steering tomorrow and see if it still moves. There was no visible wear to the vert link but I can't see/think what else it could be. The holes in the wishbone aren't ovalised. Opinions would be very gratefully received as my MOT tester isn't very leniant and the retest is on thursday...

[ben711200]

ouch! I appear to have fallen off of the front page.

Sorry for extra bumping, I'm getting a bit frustrated with the car now..

[herald948]

I can echo Seth: talk to Bill@Rarebits.

It's a while since I did a set of Herald trunions, though I'd better be looking at the 948's ones before it goes on the road. EP90 gear oil at the ready.

A slight bit of movement due to the steering is not entirely unexpected. Just how much movement do you have?

[Seth]

What did you replace in the end?

Is it not wheel bearing wobble? There's always a bit of movement on these. Presumably you had the hubs off anyway to change the trunnions so did you do the hub nuts back up correctly? (ie do it up until bearing it starts feeling tight and there is no play, then back it off a little)

Another possibility would be the rack bushes where it mounts on the chassis

[ben711200]

I rather lazily replaced the trunnions as complete units and am confident that they are in correctly with no movement being caused by them or the wishbone they are attached to..

I did the hub nuts up as you said, and there doesn't appear to be any play in the wheel bearings. I'll check again later though. I'm also going to disconnect steering rods in order to see if it still feels the same.

There isn't much movement, but it is easy to feel with hands firmly grasped either side of the wheel.. I'm just not sure where exactly it is coming from!

I'm slightly at a loss really, I think I'll know more later. Thanks to everyone for your help and suggestions though, it gives me a bit of an idea what else to look at

[ben711200]

Looks like my Dad was right.. Wiggle wheel=play. disconnect steering arms=no unwanted play in any direction. Bloody fathers always being right ;D

So now I need to wing it at the MOT station.. I have my retest tomorrow and have repaired the fail items, even if one or two of them were actually incorrectly diagnosed and not the cause of the movement... I'm not sure how I stand on this, but I'll tell the MOT tester what I've done and what I found when it was stripped down and put back together. He may try to call Bullplop and fail me anyway but I suppose it's worth a go. A retest only tests the fail items, afterall, and so these parts would pass, technically. I don't know. A bit of an odd situation

[Seth]

So that's got to be track rod ends, the rack mounts or the rack itself. Check that the nuts on teh U-bolts that hold the rack in are nice and tight. You are allowed a little bit of movement/play in the rack but not much. Hope it goes OK at the re-test

[ben711200]

Oct 21, 2009 23:34:38 GMT Seth said:

So that's got to be track rod ends, the rack mounts or the rack itself. Check that the nuts on teh U-bolts that hold the rack in are nice and tight. You are allowed a little bit of movement/play in the rack but not much. Hope it goes OK at the re-test

Thanks


It PASSED! I told the guy in the garage about the play and he ummed and ahhed about it.. It was a small amount of play in the rack, he passed and advised it. The cheeky blighter knew I wasn't too sure whether it'd pass though. He went to pick up a red certificate when I walked in to get me worried, then started laughing and gave me the real one ;D

[herald948]

Well done!

[joethefish]

Result!

[ben711200]

Cheers guys It's going to be going to a new home now, and I get the feeling it will get much love but I'm really going to miss it. Driving it about after it passing was probably the worst thing I could do.. It just reminded me how fun it is.


Joe, you have an unrelated PM

[joethefish]

Sold finally..? double result! See you later mate