I have just installed my new front disc brakes using a set of four spot calipers, the rears are a set of CB performance rotohubs, i have not been able to get a consistant brake pedal, after it was bleed the pedal was good but then after some use it began to increase in travel, i had a look at the calipers and there was no drag on the rotor's and the pads had moved away from the disc's, i ordered a set of 2LB residual valves and installed them today, what a difference, the brakes now have a small amount of drag but there is no increase in pedal travel with use, the pedal has good feel and does not change, if you are having a issue with to much travel on a disc brake conversion a larger diameter master cylinder is not necessarly the answer, if the pads are moving away from the rotor's this could be the fix.

where did you get them from?

on VW [ate etc[ disc brake master cylinders there are residual valves to keep slight pressure on the front calipers.
the residual valves screwed into the top of the [disc] master cylinder and the two front pipe fittings screwed into them.

on USA front drum brake master cylinders [no beetles had discs in the USA] the pipe fittings screwed straight into the master cylinder and were a different size so the two different master cylinders couldn't be used by mistake..

as the pipe fittings for drums didn't fit the disc master cylinders with or without the residual valves...
[Only Karmann Ghias had discs in the USA]


LEE

Wilwood make a 2lb and a 10lb residual valve, the only master cylinders with residual valves that i have seen on a vw was the drum brake 74 poverty pack beetle, i have never seen them on a disc brake master cylinder, live and learn.