One of the things that isn't mentioned much is the position of the pistons in ther bores. If they are fully retracted there isn't enough stroke in the MC to push them out enough to contact the rotors. When you pump the MC, what travel you get out of the pistons is reversed each stroke by the dust seals pulling them back.. This problem is made a little worse because of the smaller than stock MC bore. I think that by tying the brake lever overnight, the dust seals relax (slip) a bit and not retract the pistons as far when the brake is released, leaving them in position to push farther on the next stroke,
When I assemble calipers, I leave the pistons extended so that when the pads are in, the assembly fits over the rotor with little clearance and find bleeding goes much easier.
A way to get more MC piston travel when working with a stock under tank MC, is to diconnect the linkage and push the MC piston with a big phillips screwdriver when bleeding. This added stroke is often enough to push the caliper pistons far enough to slip into a new position on the dust seals and the seals can't retact them as far.
So much riding-so little time
Xcuvator screwed with this post 01-24-2012 at 08:12 AM