Breva/Griso CARC Housing Breather Warning!

Beware! A potential problem here.

My (brass) breather fitting was rather loose when I first checked it but didn't feel "right" as I tried to tighten it so I removed it and refitted it with Loctite, tightening it very carefully. There was no way it would have taken the recommended torque setting.

Recently there was some slight oil seepage around the breather so I removed it again and found that it had started to shear off at the uppermost thread root. Not only was the thread cut very deeply but there was no root radiusing. It was also only about 6mm long whereas an M10 thread should be at least 10mm long. The CARC housing has more than 10mm of thread, which is ideal.

Replacing the breather would not have moved the situation forward enough, so I opted to modify the breather. The failed thread was cut off and the upper portion of the breather brazed onto the top of an M10x12mm steel hex set screw, bored 4mm. Now there is a full thread connection and the whole thing feels like it should.

The handbook advises removing the breather when changing the final drive oil. Since the breather is only acting as an air vent I can't see the point of that, and because the thing is so fragile and short threaded I'd recommend leaving well alone. Failure of the breather could see oil misting get onto the tyre and brake and cause a serious loss of oil.

Graham Allardice - galadik<at>actrix.co.nz -- replace <at> with @.