SGD

I bought this car two years ago in May. The car is in great shape. I only had to catch up on a few years of maintenance and small repiars. I only drive this in the summer months as it has no rust. (California car). Last summer I put up with the brake light on the dash flickering thinking I had to do some work to the e-break components. I put it off until fall when I got the car ready to put up. After some fooling around I discovered the brake fluid level switches and added some brake fluid. (DOT 4) this is the fluid stated on the resevoir cap. When I inspected the underside of the car I noticed some oil around the bottom of the bell housing. (This thing never leaked a drop)After the car sat for four months I noticed a lake of oil running out from under the car and determined it to be brake fluid. I changed the clutch slave and when I went to see about bleeding I discovered brake fluid leaking around the rubber plugs that the resovior is pushed into and the hose feeding the clutch master cylinder was swelling and leaking. What happened! Anyone have any advice before I add new fluid to the new master cylinder and start bleeding everything? Thanks