Rear master cylinders... Do they go wrong?

[mr self destruct]

No direct experience with an MC failure, but I'd say it was highly unlikely an MC will stick.  It's more likely to leak, leading to less power to the brake.  More likely is it being held by the pedal mechanism, or perhaps you've just been unlucky with the calipers sticking.

Are you sure you've not been accidently resting on the pedal when riding? 

How long has the new caliper been on, and how often have you given it a clean (general clean, when it's on the bike - not a service/clean).

Knowing my luck the caliper could be shagged!  :rollin It's been on about two months I reckon and the bike's been cleaned at least once a week, but i do 250 miles a week in all weathers so could get gunked up.


I make a point of riding with the balls of my feet on the pegs, so resting my foot on the pedal isn't the problem.


I got home last night (after riding from work without touching it as it had freed off during my shift) and gave the pedal spindle a soaking with carb & brake cleaner, then WD40. Didn't touch it on the way in to work today but I'll see how it is on the way home, as at least I can get AA'd if it goes a bollock again.