Hi all

the rear caliper on my bike is sticking (08 fatboy)
I noticed as the pads wore down very quickly and the rear disc was hot as hell

I have done the following,

Bled entire system with DOT 4 (as recommended on MC cap)
confirmed brake pedal is returning all the way up (returns very easily)
confirmed return in master is not blocked (can see the fluid movement )
no kinks or crimp in lines
greased all sliders at caliper
Confirmed that the rotor is not bent / warped and rear wheel is aligned correctly + wheel bearings all good
took off caliper and noticed that the lower piston comes out slower than the upper one when pushing brake pedal
removed both pistons and no scoring, actually looks very clean inside and I cleaned polished the pistons however they were not dirty at all - reinstalled and no difference
seals look great, no nicks or anything. carefully removed and ensured no buildup behind them & put back together - no difference
Used PBR assembly grease and even when removing the piston again, smearing grease on it and the seals went in a little easier but when pulling them out and pushing back in was extremely difficult
Could it be the seals just gone off / hard / lost elasticity? they seem pliable but its all I can think of as when I push the pistons back in they require a fair bit of force - this is when I had the caliper on the bench with no bleeder valve installed so there was no air lock happening

A lot of detail above but just giving as much info as possible

Driving me effing nuts........

thanks
rob

This happened to my Wideglide and it was the foot pedal causing the problem as it was seizing in the pivot, I removed foot peg and pedal cleaned it up and put some anti-seize lube on it

The caliper should be able to move back on fourth from the top mounting bolt and pivot on the bottom bolt it should pull down on the rotar when brake is applied then lift up when released this movment is only a couple of MM make sure you clean the mounting bolts and caliper holes and lightly grease with the right grease and tighten them to spec.

Thanks

I have used the blue bendix high temp grease on the pins & sliders and theyre all fine
pretty sure its the square seal in the caliper on one piston that is not working properly as a return spring, the piston is really hard to push back in with the seals in place yet when seals removed drops right in
gonna re seal it tonight and i'll let you all know

Wideglider, the pivot doesnt appear  to be binding at all, its returning easily and even if I then pull back on the pedal it doesnt come back any further

This an ABS bike......?

no, good ol normal brakes 

new seals & pistons in and so far so good
on the bike lift the rear wheel turns freely, apply brake & release and wheel turns freely again just has that very light pad to disc sound which the HD tech  I spoke to today is normal
pedal even feels better, last night was stiff from the word go and now its more progressive
last night after applying brake and releasing the wheel would not turn and when I could finally turn it was very difficult
will take for a spin tomorrow

Rather than a 2 piston push/pull caliper should be a single like my dirtbike, 20 yrs old, been through mud and all sorts of shit and just has fluid changed when pads are and has never stuck like this