Loctite 638 or 641?

[david.g.chapman]

I am in a quandry.
While I am changing the rear bearings I had a look at the passenger side diff output shaft, and noticed that the output bearing had just started to spin in the diff housing. I removed the diff output shaft, and I measured the play between the bearing and the housing - happily insignificant (less then 0.05mm), but enough for the bearing to move.

I am tempted to use high strength Loctite 638 to secure the bearing, but I might never be able to get it out again. Should I be using medium strength 641 instead?

Dave Chapman.

[RichardHawkins]

Dave,

I suggest you speak to someone at the loctite technical advice service. I also think that the load on the bearing will vary depending on whether you are using rotaflex or CV couplings. I think that the rotaflex will exert more load on the bearing as they flex than the CV will.

If I remember correctly loctite can be released by heat, but I cannot remember how much, again loctite tech advice could probably help.

Richard Hawkins

[nomad]

680 and it will never move! Used it on all manner of nasty worn bearing housings.

Kurt

[david.g.chapman]

After looking at the specs, I will go for 680. It looks most suitable for slip fit bearings on a rotating shaft.
A heat gun should enable disassembly in future.

Thanks to both of you.
Dave.

[snowyelan]

Regarding the heat, I recently pulled 2 rear hubs from their shafts. One had blue and one red loctite. I'm assuming regular threadlock in removable and permanent types based on the color. Beans catalogue states that they 'float off' when heated which is exactly what I observed. I would suggest you pick the best based on what is required and assume the heat will break the bond regardless of type. My 2 cents anyway.

[david.g.chapman]

Thanks again.

I will go for 680 on the slip fit situation and probably general threadlocker/bearing fit on unworn housings with an interference fit. Halfords here in the UK sell the threadlocker for just ?4, which is similar to 638.

Dave.

[jono]

I actually used 660 in this situation due to its gap filling properties and it worked perfectly.

Unfortunately one of the new lip seals subsequently failed so I had to have it apart again after only 300 miles - with heat it came out quite easily and the bearing showed no signs of spinning which was good to see.

I've now done many more miles and no issues.