What Could Cause a Trailer Oil Bath Cap to Crack

Question:

I would like like to no why these caps on a drv new just broke. We drove all day and hit rain storm then thats where problem was noticed. Is it because hub is warm and hit cold water? If this is the case do they make a threaded one in metal?

asked by: Randy L

Helpful Expert Reply:

It is entirely possible that the cap for an oil bath hub could get warm enough that touching cold water could cause it to crack but the cap would have to be very hot for that to happen. It is unlikely that it would get that hot unless there was no oil in the hub so you will want to check that for sure.

Also if the caps were over-tightened that could stress them and then, once moving, the centrifugal force could cause further damage.

We have several different oil caps, see link, but none that are metal.

expert reply by: Michael H