Lotus Elan

Getting a trunion off.

PostPost by: billwill » Sun Mar 15, 2015 7:30 pm

Late last year I tried to get my left trunnion off to change it, but I found that the bolt that connects to the two lower wishbone swinging arms has siezed in its bush and won't come out, so I put it all back together for the time being.

I tried heavy persuasion with a big hammer on a drift onto the bolt shaft with a nut positioned flush with the end and I tried plus-gas all to no avail.

I can't see how heating would work as the siezed bit is in the centre of a rubber bush.

Not sure if I can get the lower arms off the chassis; though that looks the best possibility from my armchair. I think I can get the nut off so I possibly only need to undo from the chassis the wishbone that is held to the trunnion by the head of the bolt. Hopefully I will then be able to srew the trunion down until it coms off the vertical link.

Once 'on the bench' I will be able try try other creative methods of getting the bolt out.

Anybody else got any suggestions.. Other than make sure to put copperslip in there next time? :D
Bill Williams

36/6725 S3 Coupe OGU108E Yellow over Black.
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PostPost by: AHM » Sun Mar 15, 2015 8:21 pm

Bill,

The steel tube in the centre of the trunion slides out of the trunion bush, which is in 2 halves that come out of the trunion. So removing the arm with the seized parts of bush and without the trunion should be easy enough.
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PostPost by: Elanman99 » Sun Mar 15, 2015 9:44 pm

As you say you cannot remove the lower wishbones off the car until you can separate them. If they are held together by the trunnion or the lower damper bolt then in order to dismantle the suspension to get it to the bench I would drill off the head of the problem bolt. (Its probably easier to drill off the head than it is to remove the nut by some means).

I suspect that other bolts and bushes of the front suspension might have bonded themselves together so get ready for more fun!

Ian
68 Elan S4 DHC. Built in a weekend from a kit (just like the advert said)
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PostPost by: rgh0 » Sun Mar 15, 2015 10:02 pm

AHM wrote:Bill,

The steel tube in the centre of the trunion slides out of the trunion bush, which is in 2 halves that come out of the trunion. So removing the arm with the seized parts of bush and without the trunion should be easy enough.



Hi Bill
That was my approach many years ago when I first got my Elan and it had a similarly seized bolt in the sleeve.
I took off the nuts and pulled off the rear wishbone arm. I then removed the chassis nuit and shocker bolt so I could pull the front wishbone arm forward bringing the bolt and sleeve out of the trunnion. I then had the bolt and siezed sleeve and front lower wishbone arm separated from the car and could hacksaw the bolt to remove it from the trunnion.


cheers
Rohan
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PostPost by: billwill » Mon Mar 16, 2015 12:53 pm

Elanman99 wrote:As you say you cannot remove the lower wishbones off the car until you can separate them. If they are held together by the trunnion or the lower damper bolt then in order to dismantle the suspension to get it to the bench I would drill off the head of the problem bolt. (Its probably easier to drill off the head than it is to remove the nut by some means).

I suspect that other bolts and bushes of the front suspension might have bonded themselves together so get ready for more fun!

Ian



The nut itself is not siezed on the trunnion bolt, 'merely' the bolt siezed in the trunnion fittings. So I don't need to drill the head off, if I can undo the chassis nut at the other end of the wishbone. And if the wishbone will come off at the chassis end.
Bill Williams

36/6725 S3 Coupe OGU108E Yellow over Black.
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PostPost by: simonknee » Thu Mar 19, 2015 10:38 am

You should heat it up then cool it down quickly. This could break the seize. I recently got one of these and boy has it made life easier:

http://www.screwfix.com/p/rothenberger- ... nder/99810

However if you have not taken off the wishbone then you will still have the little metal discs in place an if one of these is snagging in the bolt thread you could be going nowhere. Perhaps take off the one wishbone that is removeable. i.e. on the nut side of the trunion
Simon
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PostPost by: elan66 » Thu Mar 19, 2015 5:49 pm

those gas guns are great but be careful using the yellow map gas near any alloy etc as if i remember they burn a fair bit hotter than the standard bottles,but yes great bit of kit
regards
Paul
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PostPost by: simonknee » Thu Mar 19, 2015 9:27 pm

Yep, the yellow cans are very hot but it came with a standard blue butane can too for the price. The MAP gas is just the ticket for those rear hubs, though I won't go playing it over the hub carriers. The ability to get a lot of heat in quickly is brilliant.
Simon
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