trunnion nuts

Post by dp » Sat Sep 06, 2008 8:40 am

I recently lost the upper right hand trunnion nut together with the knock flat washer and the thick washer. (Not the castellated nut, the one at the rear).

When I say lost, I mean the nut's come loose and dropped off. Luckily someone spotted this.

Easy enough to replace, but does their absence indicate something else amiss?

Should I replace the trunnion pins or indeed the whole upper trunnions on both sides; or just the missing nut and washers?

I'm quite concerned that the nut would work loose like that and wonder if it's a symptom of another problem.

Thanks

Post by **aupickup** » Sat Sep 06, 2008 8:46 am

well it should be a castle nut with a split pin

Post by dp » Sat Sep 06, 2008 9:35 am

That's at the front of the pin, at the rear it's a plain nut and knock flat washer. Unless there are several types?

Post by **Dean** » Sat Sep 06, 2008 10:13 am

I think it's a naff way of holding a nut on, I know the nut can't be tightened up fully to stop locking the suspension. But, I find there is too much play in the washer on the shaft to actually stop the nut from eventually working off. Nipping the nut up seems the only real safe way to me. I'm looking forward to anyone commenting who has lots of experience with this.

dp, I don't think there is anything wrong with your suspension, what has happened is maybe your flat locating washer has worn due to movement in the way the washer locates. The flats on your shaft may be worn also.

Post by **aupickup** » Sat Sep 06, 2008 3:00 pm

had no problems with these in over 20 years of morris minor motering

Post by **bmcecosse** » Sat Sep 06, 2008 4:53 pm

Not happened to me either - wouldn't worry about it - the washer should hold it - but if concerned either use a spot of Loctite - or drill through nut and pin and apply split pin - or wire to lock it!

Post by **minor_hickup** » Sat Sep 06, 2008 8:18 pm

Its happened to me! I stopped to check what that graunching sound was and found the damper link pin sitting in the top trunnionwith no bolt and only one bush!! It was re-attached with a good dollop of permanent loctite!

Post by **Dean** » Sun Sep 07, 2008 12:18 pm

bmcecosse wrote: or drill through nut and pin and apply split pin - or wire to lock it!

I like that idea!

Cheers

Post by dp » Tue Sep 09, 2008 8:33 pm

I wonder what's the engineering thinking for sticking a castellated nut and split pin at one end but a tab washer at the other....

Post by **bmcecosse** » Tue Sep 09, 2008 8:40 pm

That is the end that's to be dismantled - for renewing the bushes, I guess.

Post by **PSL184** » Tue Sep 09, 2008 9:07 pm

The rear has the lock washer so you can acurately set the 25 thou free play measured at the front end. If the rear had a split pin you wouldn't be able to set the free play accurately enough as you would always be between flats.

Post by **stag36587** » Wed Sep 10, 2008 12:12 am

Ah - I knew there had to be some logic to that!

Post by **Dean** » Wed Sep 10, 2008 11:59 am

I've been thinking about this, another way is to lock another nut behind it.

Post by **PSL184** » Wed Sep 10, 2008 12:06 pm

Assuming you have enough thread exposed to do this?
If the locking tab is replaced, as it should be, after assembling the trunnion then I don't see how it would come loose. I can understand though if the tab is not replaced or not fitted correctly as this nut should not be done up tight......

Post by **bmcecosse** » Wed Sep 10, 2008 1:40 pm

25 thou free play ?? Mine is belted up to the end of the thread - but with hard polyurethane bushes in there.

Post by **PSL184** » Wed Sep 10, 2008 1:55 pm

Plain pivot pins require the free play to prevent the steering from locking up. I assumed these type are fitted in the question here due to the locking washer been fitted which is not needed if screwed pivot pins are used (which don't require any free play).