Mac 10t clutch replacement

[oldwahoo54]

One of my weekend projects is to replace the clutch in my Mac 10t. I watched a couple of youtube videos that em3ev sent me of someone doing an R&R of a BMC motor. He sealed the cover to the hub case with some Permatex. However, when I removed my cover it had no gasket material from before, so I'm thinking maybe it doesn't need it. I rarely ride in the rain and even if I did, the way it's covered by bags and all I don't think it's going to get that wet, plus you've got centrifugal force and heat going for you.

Am I missing something?

 

[teklektik]

I run BMCs and used to seal them but stopped after I collected some water on more than one occasion.

Justin pointed out that cooling a sealed motor lowers the interior pressure and sucks moisture/water in - where it can't get out. So - I drilled my motor covers with a 1/16" hole to line up with the interior edge of the case. This pretty much flings any water out and relieves any pressure differential so nothing gets sucked in. Motors have been dry since doing so, even fording streams with the motors partially submerged. Motors pop apart easier for service as well.

Anyhow - with a vent hole drilled, sealing them seemed pointless...


See BMC gear replacement stuff - here.
There's also MAC tear down stuff on ES - here.

 

[dogman dan]

That vent hole trick works so good, I'm amazed it's not standard on motors. You can't avoid that suction when the motor cools, but with the hole in the right spot, it will expel any water that does condense inside when you run it.