Help - Trunnion Trouble?

PostPost by: david.g.chapman » Fri Dec 15, 2006 5:07 pm

This has been discussed before, but I could not find a definite answer.

Does anyone know how much play is acceptable on the trunnions? I have my +2 jacked up and the front suspension unloaded. I have removed the steering rack, shock absorbers and anti roll bar.

As I raise the hub by hand, I can see the top of the trunnion rocking with respect to the vertical link by about 20 thou. This equates to about 8 mm of suspension travel. Everything then moves as one as you continue to lift. Both sides are the same.

There is no side to side movement, and the action of the trunnion is smooth as the hub is "steered". I would replace the trunnions, but I am having trouble removing the trunnion bolts and I am afraid that too much force will bend the vertical link threaded section :shock: .

Dave Chapman.
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PostPost by: rgh0 » Sat Dec 16, 2006 3:35 am

Hi david

I measured a worn trunnion on a old vertical link. I had removed the trunnion many years ago as I considered it had to much free play.

My worn trunnion had 0.008 inch movement measured at the ends when rocked from side to side on the link and less than 0.001 inch axial movement when push up and down.

From your description it appears yours need replacment.

Have you got the nut off the bolt? If not and you cant move it then grind it off or use a nut splitter. If the nut is off and you cant get the bolt out then the bolt is probably rusted in the sleeve. Lots of penetrating oil may free it up. If not then remove the whole vetical link and bottom arms from the chassis and press the bolt out or grind the head off the bolt to remove the other arm from the trunnion.

regards
Rohan
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PostPost by: john.p.clegg » Sat Dec 16, 2006 7:28 am

Rohan
IMHO I don't think you can get a nut splitter or a grinder into the arms onto the nuts/head and the only way out is to drill the bolt or put your grinder through the trunion.....
or maybe I'm mistaken.....have been before....

John :wink:
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PostPost by: david.g.chapman » Sat Dec 16, 2006 8:29 am

Thanks a lot for your replies. I have the nut off and can turn the bolt both sides. I will try harder :wink:

PS.
I have just ordered new trunnions from CN + the bushes and bolts. Now where is that Dremel... :twisted:

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PostPost by: rgh0 » Sat Dec 16, 2006 11:01 pm

John

You are right about the nut splitter not fitting, I had a quick try to get mine on the nut and the lip around the suspension arm prevents good contact. For grinding you need a small wheel on a dremel as a standard 100mm angle grinder is to big and you will end up cutting the suspension arm unless you have very very steady hands.

As you observe probably easiest to cut through the trunnion itself since you are replacing it anyway.

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PostPost by: elansprint71 » Tue Dec 19, 2006 6:53 pm

If it all ends in tears, new uprights are available from Rimmer bros and will not break the bank.

Pete.
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PostPost by: david.g.chapman » Thu Dec 21, 2006 12:27 pm

I have both trunnions off now. Whith the nut off, I ended up hammering a large chisel into the gap between the lower wishbone and the first bush washer, using it as a wedge. by then levering against the trunnion body I was able to work the metal tube away out of the trunnion, as it's held in by nylon bush pieces. That way there is not much stress on the vertical link.

I am now left with the bolt retained on the other wishbone by its head, and the metal tube which is seized solid. I will cut through both with a grinder near this wishbone and I will be OK.

One question though. For a new arrangement, what part actually rotates? there is a fair amount of play between the new bush and its metal tube. I am assuming this is clamped together and the trunnion rotates on the nylon bush?

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PostPost by: rgh0 » Fri Dec 22, 2006 6:19 am

Dave

The inner steel tube is clamped by the bolt to the arms and the trunnion and nylon bushes rotate on the inner tube. Make sure you put some antisieze on the bolt when assembling to prevent the tube rusting on to the bolt.

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PostPost by: david.g.chapman » Fri Dec 22, 2006 10:57 am

Thanks Rohan,

This forum is the best! :D

A Merry Chrismas and Happy New Year to you all.

I hope to give some input on steel wheel balancing and front shock spring changing next year.

Dave Chapman.
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