I had this on my earlybay after fitting a new mcylinder I ended up having to adjust the pushrod to give 1mm freeplay or clearance.It was fine cold but after a run would get warm and bind.You will be able to tell if this is the fault by loosening the bleed screw when it binds if fluid comes out under a bit of pressure and then does not bind bingo bango bobs your uncle.
it is the pushrod that is adjustable that is between the pedal and the mastercylinder.It just needs a bit of freeplay.
Whatever it is steve will sort without ripping me off . i asked him to put new drums and shoes on last week but he told me the price he could get them for and said if i want to source them cheaper then he would do em weds. i have to defend steve he is the last of the old achool garages in our area and he knows vws . he said right away they have problems with hoses breaking down . i just told him about the mc post .
I'm guessing some jiggery pokery involving flexis and mole grips cos thats the method all good mechanics use isnt it. If it was fine before and it isnt now and all thats been fitted is a wheel cylinder then what in the blazes did he do to fit it. Brakes can be a little confusing and you need to be methodical. Particularly when bleeding them up. I'm suspecting rear hoses are both collapsed after being clamped up trying to get a pedal as they wouldnt bleed properly! Or possibly only the one - are both hubs hot or just the one?
Did you remove the compensator during the resto? If so did you put it back in the same way round it came out?
Forget that you said it was all fine untill they changed the wheel cylinder Where your brake flexis old or new ones?
