| Agree with twpd, replace seals, clean everything, lube with brake fluid ( the seal is designed not to swell or react with that) then every so often move pistons in and out fully. Happens all the time on mountain bikes where you notice it immediately as the pad won't retract fully and you get a slight rub ( which all mountain bikers think is slowing them down), most mess around for days trying to shim the caliper but its probably the seal dry, moving the pistons in and out cures it. All that pulls the piston back in the seal. GPR should know however and if they suggest grease use that and then keep moving pistons in and out. |