REASSEMBLY AND BLEEDING
Fit master cylinder 1
Start by attaching the unions – it’ll be easier to start them in their threads before bolting the cylinder down. Take care not to cross-thread them. Fit new hoses to the reservoir, if it’s remote.
Tighten unions 2
Check that all the unions in the system are tight – but never screw copper pipe unions down with excessive force. If compressed too far, the flare can be fatally weakened, leading to sudden failure.
Fill master cylinder 3
Fill the reservoir with fluid. Unscrew the master cylinder union(s) a little way and tickle the pedal slightly until fluid leaks out, indicating that the cylinder is full. Now tighten the unions fully.
Start bleeding 4
Fit a pipe leading to a clean jar to the nipple furthest from the master cylinder. Get an assistant to pump the pedal three times, then hold it down. Undo the nipple a quarter of a turn, then retighten.
Finish bleeding 5
Repeat until clean, bubble-free fluid issues from the pipe. Go round all the nipples in this way, ending with the one closest to the master cylinder. The system is now full of fluid. Check for leaks.
Final checks 6
Let it rest overnight. Air will collect beneath each nipple. Bleed the system briefly to release this. Now test the system by standing hard on the pedal for 30 seconds. If it starts to sink – find the leak!