05 SLT 5.7 2 Wheel abs
I have replaced firewall to rotors. Booster, Master cyl, brake lines, calipers, rotors and pads. Still after driving maybe 40 or so miles, sometimes less sometimes more, no panic stops, maybe a dozen slows or stops then the front brakes begin to apply and lock up even without applying brakes.
Slept in truck memorial Day, just me and the mosquitoes waiting for GEICO. Too old for this crap. PLEASE, I'm a 75yr old vet that used to be a certified mech who now is dumb and desperate...

 

2 or 4 wheel ABS?

You don't seem to be the only person suffering from mystery brake application....... Real curious what is going on there..

 

2 wheel abs

 

Not what I expected........ and all the parts are new, including the soft lines to each wheel?

 

new parts can be faulty....more and more common, where did you source everything? sounds to me like a master or booster issue

how did you bleed the brakes? a new master would still require the bleed sequence in the ABS module, regardless of 2 or 4wheel i believe?

 

2 wheel abs only has a dump valve on the rear line. So, no special bleed procedure required.

 

All parts were rock auto, no economy listed stuff. When I say locked up...not a panic stop type, slowly in a matter of moments. Since it's both front wheels I feel it's got to be something in common so with new booster in transit...
By the way, it's a hell of a lot easier to replace those pesky back spark plugs if needed less booster.

 

Replaced booster, after multiple road tests, brakes no longer drag and lockup
Replaced booster had little pedal free play, new one significantly more. I feel the problem is the adjustment of the pushrod. There MUST be correct specific set length. Y'all are lots smarter than my old butt but if someone knows and post it, I'm sure it would help others.
V/R

 

If there is any adjustment at all, it'll be down at the pedal..... But, so far as I know, there isn't one.....