Just picked up a second hand stumpjumper and its pristine apart from a set of rear pads. Went to replace them tonight and i can't push the pistons all the way back in to enable the new pads plus clearance for the rotor.
Do i need to do anything further to enable the pisons to fully retract? Could this be air in the system or too much fluid? Will bleeding help?
Thanks.
Have those got the pad contact adjust thing, like a red barrel where the hose meets the lever body? If so then you need to make sure that it's wound all the way out. It can be confusing which way it needs to be wound so just try it both ways.
Damn, just googled and you don't have the pad adjust, SORRY!
Yeah, no doesn't have that.
Yeah, sorry I should have googled first, mine have the pad adjust and it always catches me out.
I reckon you're spot on, too much fluid in the system. Bleed it with the proper bleed block in there and you should be sorted. I've never had to do it with Avids but I've had to do it with a few sets of Hopes where the pads were touching the rotors. If they're 2nd hand then a bleed is quick and it's not a bad idea to change your fluid anyway since you won't know when it was last done.
Cheers, that was my thought. Always worth bleeding.
LHS,
I had exactly the same issue on my Scott, i took it to my LBS they explained that some times original brake pads that come on a bike from new are thinner than the replacement ones. The knock on affect is when when we try and replace them there is to much fluid in the system. Since they adjusted it i have had know issues, hope this helps.