Every time I get an inspection the shop tells me I have a master cylinder leak. After hearing about it for over 10 years. Maybe I will think about diving into it. Is this a driveway repair?

 

There is a seal in the back end of the master cylinder to keep the fluid in. When the seal goes bad, brake fluid leaks out and runs down the booster. It can also leak into the booster. Brake fluid eats paint, so look for missing paint directly underneath. Another check is to unbolt the master cylinder and pull it forward just enough to slip the corner of a paper towel or q-tip back there. It should be bone dry. If you see brake fluid, the master cylinder is leaking.

 

I concur, that information is spot on. Yes, you can change the master cylinder in the driveway, although you'll have to bleed the brakes. Be sure you prime and bleed the MC before you install it.

 

dose it cause a vacuum leak? i checked the vac-lines no leak on them