Loose/leaking cap on rear transmission case

[akershaw]

I'm rebuilding my gearbox and discovered that the metal cap built into the rear transmission case is loose and leaking oil. Inside the cap are circular score marks where the countershaft has rotated against it. There are no corresponding wear marks on the countershaft or the nut, suggesting that the cap was damaged before the last rebuild of the gearbox. This is supported by the presence of sealant around the cap - clearly smeared on from the outside and predictably ineffective.

I don't really want to replace the rear transmission case so would like to find a way to seal up the cap. My thoughts are:
a. Gently tap on the centre of the outside of the cap to expand it into the flanges around the edges - this relies on the countershaft no longer forcing it backwards
b. From the outside, cover the edges of the cap with flux and then melt some solder into the join between the cap and the transmission case, in the hope that the solder will seep into the gap and seal the leak.

It would be a pain if these measures don't solve the problem, so just wanted to check if anyone has any better ideas.

Thanks in advance.
Alex

[davidbruce]

Loctite make a couple of threadlockers (290 and 294) designed to work by capillary action into fasteners already assembled. I have no experience with them but may be worth investigating.