Purple Martin wrote:You must change the master to the dual-circuit kind because:
- Drum brakes have small slave cylinders (the ones at the wheel with the adjusting stars) which only need a small volume of fluid to operate them.
- Disk brakes have big slave cylinders (to push the calipers) which need a larger volume of fluid to operate them.
The older single-circuit master only moves a small volume of fluid (fine for drums) and the newer dual-circuit master moves a larger volume of fluid (necessary for disks).
Fortunately, changing the master is an easy job. If you need a new hard line or two you can get them made for you cheaply at most good brake workshops.
Also change the fluid reservoir (hiding behind the spare wheel) to the dual-circuit kind with two halves and two hoses running from the reservoir to the new dual-circuit master.
Some truth in that but in reality the disc caliper sits the pads far closer to the disc than wheel cyl does the shoes and the stroke of the MC can easily handle both setups. Main thing is the single holds residual pressure for the drums but this will keep small pressure in a disc setup and cause the disc to overheat from constant pad contact.