04 trailblazer, brakes dragging after new pads, calipers, master cylinder

[Mooseman]

I doubt very much the dust shield removed does anything as the caliper is a floating type and basically self centers over rotor. We're talking a fraction of a mm here. Lots of people, including myself, have removed them without any issues.

You seem to be on the right track for the MC and booster issues. Try disconnecting the brake pedal to booster rod and see if it moves further back than the pedal. I am willing to bet that it's the piston pusher pill in the booster to MC that's the problem. I remember faintly that someone had the same issue and it was this pill that was too long.

 

[BradyinKy]

I've heard of that, and I basically did the same thing by adding a couple washers between the booster and master cylinder, but that is all a bandaid for whatever the real issue is, and if it's the lack of shields at the wheels, then I just need to get those and put them back on.

 

[pwg]

It's possible that aftermarket parts might not have the exact same specs or measurements to work properly. Maybe the depth of the piston in the MC is not quite the same as the original or the pedal shaft is not quite the same on the booster or the piston pusher "pill" is just a little longer. Check and compare with the old parts. I would have no problem running it with the spacers like that.

The GM booster assembly gasket, part number 15015355, that goes between the back of the booster and the firewall is .2 inches thick which is almost 1/4 of an inch. If that is left out, or a thin after market gasket is used, it may be enough to put preload on the brake pedal and cause drag. Putting "shims" between the master cylinder and the booster would have the opposite effect. Any thoughts?

 

[Mooseman]

Well no. A shim or thick gasket between the booster and firewall would only bring the brake pedal down with no other effect. Putting shims between the booster and MC would add space between the push "pill" and the MC's piston