Honestly….. Mine is the same! I took out the central cover and cleaned and lubricated the linkage (it’s pretty crude). Then I did bleed in fresh fluid when I got it, and checked the calipers and inside the rear drums, and all was clean and well adjusted. I suspect a smaller diameter master cylinder would make a difference, but I just “stand on it”……. It runs so well I just left it alone. Is yours the Subaru 650?