I had the diaphragm in my Scott master cylinder blow out. When you take it apart you will find a pretty strong spring that is pushed by the peddle compressing the diaphragm. I got a new diaphragm from Univar. The spring makes the replacement of the diaphragm almost impossible. However here is the trick, new to me old to others, that makes the job take only 60 min or less. Remove the seat cousin and canvas. The part of the master cylinder that has the brake filler hole and the brake line hole, the cover, also holds the spring. Take a length of safety wire, run it through the two holes and through the top of the spring. Compress the spring with your thumb until the spring head is below the level of the cover and twist the wire until it holds the spring compressed. Now all you have to do is put the diaphragm in, the cover back on and torque down the bolts. The last thing to do before replacing the brake line is to snip the saftey wire and pull it back through the holes. It makes a really hard job easy.
Last edited:
