None, once the brakes have been relaxed a bit and especially after any
cornering (the end-float in the bearings will cause the rotor to push the
pads and pistons back a bit). Delaminated brake hoses (internally) can act
as a check-valve and stop fluid returning to the master cylinder, and this
affects one wheel only. If both wheels are affected the cause can be an
incorrectly adjusted mechanical (i.e. mounted on the pedal box) brake light
switch preventing the pedal moving back all the way and the piston from
clearing the bypass hole in the cylinder. I think the hose hole would have
to be *very* small to prevent fluid passing back, and a crushed steel pipe
could do just the same.
PaulH.
----- Original Message -----
> I am having trouble with overheating with my passenger front disc brakes
> on my '66 MGB. I have replaced a warped rotor on that wheel, but it
> doesn't seem that the pistons are returning all the way to allow free
> wheeling with the brakes not engaged. How much drag is normal on front
> discs, if any?
|