Weird brake pedal

[traxxas5308]

I have a 2006 gmc Sierra 1500 with front disc brakes and rear drums. I have been fooling around with my brakes to get them to work right. The problem is driving down the road I can step on the pedal it goes down maybe half way, the if I let up and depress the pedal one more time it has a nice pedal that depresses maybe 1/8 of the way down. It has a new master cylinder, new drum brakes, and wheel cylinders. When I did the master I bench bled it till I saw no bubbles coming out, and did maybe 30 strokes with it not bubbling. As far as brake lines I bled those twice and I am positive all of the air is out. I also double checked that my drums are still adjusted properly after the brake job. Anyone ever had this issue before or have any Ideas on what could cause this issue?

[diyer2]

Are you sure the rear drums are adjusted properly? If so I'm stumped.

[traxxas5308]

100% sure they are adjusted properly

[Gurrzt]

I would bet it is the brake hoses that are swelling when applying the brakes.

 

Have you changed them?, or are they the OEM that came with the vehicle.

 

Check into SS braided hose sets, Russell and Crown both manufacture them.

[traxxas5308]

If it where hose related, wouldn't the hoses expand and retract when I let up on the pedal. Its not consistent enough for it to be hoses I don't think.

[jdnoble18]

Wheel bearings?

[efritz]

you most likely got air into the ABS modulator valves, you will need an appropriate scantool such as a tech II or autoenginuity, snap on, etc to modulate them and clear all all the air out...