Soft Brakes
 

Diesel Jeep has extra play in the brake pedal. It makes contact, then feels soft and depresses more than usual. But if I pump it up it gets rid of the extra play.

Sound like air in the system or a bad booster? (MC is full).

Bleed the brakes to eliminate the chance of air in them. A spongy brake is usually air in the system. However, I can tell you that on my Suburban (1999 with front disk rear drum) it started to feel spongy when the front pads got low. It might have been the semi metallic pads getting soft or something but I bleed the brakes and it didn't have any air in the system. I replaced the pads with some ceramic pads, adjusted the rears and the pedal is firm again and it stops great.

Yep, if the pads are low it will feel spongy

Weird. New pads going in tomorrow. Will bleed too. Thanks guys. No pun intended :p

Had this on the Vette not long ago. It was just a bit of air in the system. Bled and refilled MC, poof, brakes again!

Attachment 989

Ive put 70k miles on these brakes. Plus whatever mileage the first owner put on them, and they were at like 70%. Insane. Im not very hard on brakes apparently.

Brakes made it feel a bit better. Bled the lines and tried to move the old fluid out, felt a bit better.

Now they feel decent again, but still a bit spongy. Imagine making light contact with your foot at low speed, just sufficient to stop the car, but after the car stops your foot compresses the pedal an additional 3 inches.


Now I dont know if Im just paranoid and it was always like that, or if something else is wrong? Ug

Booster or MC may be sub-optimal.

Brakes still stuck. Is the booster supposed to hold vacuum? Is that the best way to test it?

Any test for the MC? How does it fail?

When the master cylinder goes bad it bleeds off pressure so the peddle will go to the floor. When the booster goes bad it leaks vacuum so the brakes peddle is hard to push. Like when you try to press the brakes when the engine isn't running.

You also have ABS so the ABS system may be causing issues. Do you have any codes?

Sure it's a vacuum system and not a hydroboost system?