Review on ACDelco 18M390997 Professional Master Cylinder by Michael Mayes

Bought this master cylinder and fitted it as part of a brake job as I figured ACDelco parts were supposed to be good, after installing and bleeding the brakes I couldn't get around the block before the brakes locked and wouldn't release. After hours of trying to get it to work I took it off and put the old master cylinder back in and the brakes worked. I gave it one star because it's the least you can give it.