2 replies to this topic

[Stu1961]

I’m currently rebuilding a second gearbox, having previously driven the car the box was fitted to there were no obvious issues with the box generally. Have done a bit of reading on here and it would seem 1^st/2^nd gear selector fork wear is quite a common issue so with this in mind and on strip down and clean-up of all the gearbox parts I have done a bit of measuring and am now wondering just how much tolerance is allowable before wear of the selector forks becomes an issue as 1^st/2^nd is I feel excessively worn when compared to 3^rd/4^th though the gear change was fine. So I have measured between the contact faces of both selector forks and across the synchro hubs where they sit in the forks, on 1^st/2^nd the difference between the two is 0.015” on 3^rd/4^th the difference is only 0.004”, hope that makes some sense. Thoughts anyone?

[Spider]

The factory give a wear limit of 0.015". Once you reach that clearance, it's not advisable to use the Fork.

 

Sadly, quite a few new Forks I've been supplied with are at that or more, right out of the bag, though, there is some very slight variation between hubs.

 

The 3rd / 4th Fork you have is fine, they don't wear much as they have an almost 180⁰ contact face. These seldom need replacing.

 

Your 1st / 2nd Fork is worn and should be replaced. These do wear badly as they have small contact faces.

 

I'd suggest going down to the counter of your parts store with your Hub and feeler gauges in hand so you can check them at the counter. ideally, from new, they should have 0.002" clearance, though even at 0.001", I'd be happy.

 

There's a coff coff 'fix' of crimping the fork faces together, that I've heard spoken of and seen a few times. I'd suggest against this as the fork will wear in very fast time since the contact face is non existent, but is only working on 2 thin edges.

[Stu1961]

Thanks for the reply Chris. Right on the limit then, will get a new one and point noted about the new items being susceptible to instances of poor quality. The factory limit figure is great info for anyone having any doubt as to whether to reuse or not and makes things instantly clear.