Ongoing brake problems .originaly had no brake lights and shift lock problems .got no responses on that thread. Now car builds pressure and brakes stay locked up until a line is cracked to relieve pressure.never found solution to first problem .just ran different key on power to brake switch to get lights to work and shift lock to release

 

Master cylinder has to be bad.

You can bleed the new one on the car with a kit.

 

This is very frustrating .becuase the original problem was no lights and shift stuck in park.fuse was good switch was good.do you think master could have been part of that problem.

 

No. The master cylinder has nothing to do with brake lights. The brake lights are electrical, being operated by the brake pedal. There is no electrical connection on the master cylinder for this.

 

Are all 4 brakes locked up? I've heard a blockage in the lines or caliper can allow pressure to build, but not release. It's unlikely this would happen to all 4 brakes at once though.