I have a 97 f-150 4x4 4.6 it has 198000 on it. I have a huge issue with my brakes. First off no shop around here can figure out what is wrong with it. They are very spongy. you have to push the pedal almost to the floor before you stop, when you do hit the brakes it shakes really bad, and the back right rear also locks up. I need to fix this and I dont know how. I have replaced all brakes all rotors lines master cylinder brake booster wheel cylinders the calipers i dont know what else to replace any help would be appreciated.
could be a booster, master cylinder, bad brake line, warped rotor/drum bad e brake shoes, e brake cable broken or damaged causing the e brake to apply pressure, bad rear drum cylinder. you need to inspect your hoses and such, i would expect the vibrating to be a rotor/drum that is warped or out of round. If anyone has any other ideas they will shoot them out for you to check. I always get a second opinion, if all else fails go to the stealership, but let us try to help you out first, good luck.
I assume that you have bled all lines...if not do that in the correct order. The shaking and lock-uo on the rear can be a bad wheel bearing....that is very common. They can be bad and the seal will not even leak. Jack that corner up and grab the tire-wheel and see if it moves up and down a little. If so the bearing is bad and probably with those miles so is the axle. They make a repair sleeve for that....was a waste of money when I tried it though.