I am restoring a 1978 CB750F. I replaced the frozen solid rear master cylinder with one from a '77. I rebuilt it with a '77- '78 rebuild kit. The rebuild kit parts were identical. It is the type with the seperate reservoir connected by hose. I installed it but fluid will not move from the reservoir to the line. Took it apart, checked for blockage, everything is clear. The inlet from the reservoir into the cylinder comes in right between the seal on the piston and the seal on the spring. From what I can see the seal on the spring can not move far enough in the cylinder to clear the inlet and allow fluid to fill the line, so fluid just sits in the piston area but cannot be pumped down the line, no matter how much I pump. I am sure I am just missing something, but I am stumped. Can anyone advise?
