1999 tahoe brake issue

[mkingan]

i cannot get the spongy feel out of my brakes. 1999 tahoe z71. No open lines. All i did was brakes rotor swap. Bled then multiple times still really soft, no leaks anywhere. now i did read have to wait 10-15 secs on pump/release to let master cylinder come back but i have gotten no air. pedal seems to travel too far. now after bleeding then starting truck it travel further to floor, bad master cylinder? No ABS lights on. I'm stumped, any help/suggestions would be great. thanks

 

[96-2D-Hoe]

You may have done what I did, possibly more than once when changing my MC 3x, if when bleeding you push the pedal too far to the floor you will screw up the MC seals and it will need to be replaced. Is why they say to put a block under the pedal when bleeding.

If the brake pedal continues to move down after pumping up the pedal and holding it firmly while the engine is running your master cylinder is bad. If you change that you will need a scan tool to do the ABS bleed procedure or you will still have spongy brakes. If you've never done the ABS bleed it probably needs doing anyway as the fluid in the ABS system will be nasty. You can get some crap out the ABS by setting it off by braking ******* gravel etc and then bleeding. But that is a band aid fix as it won't completely get all the air out but will improve the pedal some.

Otherwise you could try taking off the rear wheels and adjusting them up fully to see if that helps. Or just a full bleed starting at the back might help too if the fluid is old and nasty.