yet another problem with my wonderful stang this time its the brakes

Discussion in 'Fox 5.0 Mustang Tech' started by lmarinukjr, Mar 11, 2006.

  1. ok i have a 1989 5.0l coupe.dropped it off at his shop for safety inspection.i could have done it at my shop but i got a traffic ticket for no safety sticker so i figured when i go to court it would look really shady if my license number and name was on the paper heres my list of things wrong. front brakes,front rotors,rear shoes,spring kit,drums and wheel cylinders.yeah i know it seems like a lot but i already did the front brakes and im putting a complete rear in my car tomorrow from my totaled hatch all the brakes are new. ok so heres my question i suspect that my master cylinder is bad here's why if i have the engine off and i pump the pedal it comes up really high and as soon as i start the engine the pedal drops pretty far down.what do u think?
  2. You are building line pressure when you pump the pedal. When you start the engine, you are then getting vacuum-assist. With the engine off, a good system shoukd give you a very nice and firm pedal feel when you stomp on it. If your M/C is going bad you would have to replace fluid periodically, not to mention you would start getting air in the system and that would create a very "spongy" pedal feel and it would get progressively lower to the floor with time. Also when the M/C starts going, you can notice a rusted/pitted/discolored/paint missing on the booster indicating the seal is worn. Usually if you see it at this point, replace the M/C asap, or you will be replacing both.
  3. ok so u think its just the rear wheel cylinders