Rox

Recently picked up a Sherco 125 and yes, it's the odd version with the rear fuel tank and parts bin brakes, however I actually quite like how it feels and handles. The big question is what replaces the (siezed) rear caliper. Can I go AJP or Braktec and if so, will it mate to the existing Formula master cylinder and hose set up ? Early google searches, suggest that what ever is needed will require a different sized rear wheel spacer but can't seem to find a deal of detail. Has anyone actually achieved this, I suspect that I will be doing the same for the front once they decide to give up too, so any ideas appreciated. I'm UK based and the parts to rebuild the Formula kit seem to be pretty much discontinued. (Although how you get a piston out of a one piece rear caliper looks to be impossible, after the airline has provided the least sticky one already). Many thanks for any help/advice.