jljbtm

I have a 95 Suburban 2500 4X4 that blew a rear brake line.
I replaced all the rear lines and bleed the system 3 times (no bubbles show up when bleeding)
but my brake pedal is still very low (much lower than it was) I can get the rears to lock up in a parking lot and the front lock up when in reverse, but the pedal? is low and squishy.
What am I doing wrong, PLEASE HELP

Jack

old dog

you might have to use a power bleeder .one other possibility is the proportioning valve flipped over when the hose blew and giving you front brakes only . you will have to then reset it ,i cant tell you the correct way but usually have to hold a pin in on the valve to reset it .

therewolf

Another possibility; The Master Cylinder drained of fluid, and now has to be bled.

1)-Get the bleeders from a parts store.
2)-With the M/C still on the car, disconnect the lines from the M/C,hook up the bleeders, jack up the rear of the vehicle till the M/C is level.(The fluid is a giveaway.) Now you can "Bench Bleed" the MC while it's still attached to the vehicle.
3)-Bleed all the bubbles out of the M/C, then reattach the front and rear lines, and go back to bleeding the truck(car) normally.

Consult a certified mechanic if you don't get firm,steady,even pressure on the pedal after a couple of bleed attempts. Test drive the vehicle carefully and thoroughly before bringing it back into service.

jljbtm

I did think I would have to do that.
Have not got back to that job yet, but will have to that next

Thanx

MDTAHOE

Are you sure that the rear brakes are adjusted properly. Gm product are very strange a under adjusted rear brake system will actually lock the rear brakes. Very strange huh? I would have never believed until I was shown many years ago. Also This would cause a low pedal. I would definitely proceed with the air in the lines first but if it does not get better try adjustment. Did the pedal ever go all the way to the floor. When the system is working properly the diaphragm in the master never goes all the way to the front of the bore. With age little dimples ( or ****) form inside the bore when the pedal goes all the way down it will rip the diaphragm. When we manually bleed brakes at my shop we always put a wood block under the pedal to prevent this for happening