Bent rotor bearing stems

[Tabor]

I'm not attempting this repair (at least not without professional guidance on hand), but I'm really interested in how it is done. I've seen quite a few bent, and imagine that it must be a common repair need, since the stems are needed for function and right out front for anything to smash into.

[Dan Schultz]

I routinely just bend 'em back with a whack with a rawhide mallet while they are in the housing. It's maybe a little risky but I know how to fix 'em if I break the stem off!

[sousaphone68]

The hill billy dial gauge is how I heard Mark's method described I used it on a bent mower drive shaft very useful.

[Dan Schultz]

.... it was very helpful to screw a long 50mm screw into the stems ....

That's a pretty large screw!

[Dan Schultz]

https://www.amazon.com/Axial-Head-Screw ... B016R183SG" target="_blank

Uh... that's a 3mm diameter screw by 50mm long. They didn't bother to list the pitch. Leave it to Amazon to not get everything right!

[iiipopes]

Dan's first comment comes to mind: yes, if the stem is bent, it does need fixing. And it hurts nothing to try to bend it back, because if it is so far bent that it breaks from metal fatigue when being bent back, then it needed replacing or brazing anyway.

My one question to the TNFJ: after inserting the long screw to provide both direction and something to apply the pressure rather than the stem itself, does anybody put a torch to the stem first to anneal it so it might more easily be straightened, with less risk of metal fatigue?

[Dan Schultz]

.... My one question to the TNFJ: after inserting the long screw to provide both direction and something to apply the pressure rather than the stem itself, does anybody put a torch to the stem first to anneal it so it might more easily be straightened, with less risk of metal fatigue?

My experience with rotors is that they are normally dead-soft anyway. I've never had to consider annealing a stem to bring it back straight. I've never broken one, either.

One suggestion though.... I always do this with the stop arm and the screw in place. The area above the front bearing and the stop arm is where the stem will be bent.