Fitting layshaft into roller bearing

No, did you use loctite to hold the outer in the case ?

Previously allan_branney wrote:

Yes a very small amount.

Remove the loctite, if it was used to hold a loose bearing in place then instead you will need to copper plate the OD of the bearing to restore the inference fit in the case. If it was just because you thought it would help but the bearing was not loose then it has had exactly the opposite effect.

Well you are not alone in having this issue and Old Britts are wrong to recommend locitite where its not needed.

http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=536162#Post536162

The loctite should release at 400F or 200C, as long as the steel does not blue you will be ok but you are not far off that so be very careful as steel blues at 500F or 260C.

Previously john_holmes wrote:

The loctite should release at 400F or 200C, as long as the steel does not blue you will be ok but you are not far off that so be very careful as steel blues at 500F or 260C

My Daughter who is a B. Eng bearings engineer always told me off for heating crankcases above 120C in order to removed main bearings, but what does she know -- where needs must !!!

120C is fine for a bearing sitting in an alloy case without loctite, but the loctite will hang on unitl 200C. So you can do 120C and have a bash with the hammer but the layshaft bearing is in a blind hole so what are you going to bash it with, drill through the back ? and then be left with the problem of sealing the holes.

Lesson to be learnt is to only use Loctite when needed and never on an alloy case with a steel bearing as it does not last anyway as the heat cycling will eventually cause it to lose its grip. In this case the bearing will be destroyed by the wrong running clearance so thats not an option.

Between a rock and a hard place comes to mind and glad I met this problem 25 years ago and found out on my first engine rebuild and its a lesson I have never forgot.

Try grinding the rounded head of a small coach bolt so that it is quite slim you may be able to slide it behind the rollers and give a little leverage after applying the heat but if you've gone up to 175 degrees it certainly won't be a good idea to reuse the bearing.

Tempering steel to the extent where hardening is reduced occurs between 540 and 600 degrees C by which time your gearbox case would be getting close to meltdown (650C)

spring temper is 300C and is blue