Hello & Help I have a 2003 blazer and the front brakes are not releasing - I have replaced the master cylinder, all 4 calipers & new pads plus 1 break line on drivers side to back, initially I took it to a garage to fix brake line, this Blazer had been sitting for 2-3 years because of the broken brake line so the garage changed the line & they told me I needed new rear calipers because the back brakes would not release, then a new brake bolster so I pick it up and by the time I get 10 miles I can feel the front brakes holding me back so I take it back and am told it's the abs module (we think) so I brought it back home and it gets worse as you drive farther. I did some research & found the abs fuses and took them out rebleed the front brakes and they still will hardly turn when it's jacked up --- Any Ideas would be appreciated! Thanks

 

You didn't mention if the guide pins were replaced or lubricated. This can get corroded and cause the calipers the bind. I had this happen on my rear brakes when they became corroded from exposure to salt water.

 

Yes I replaced guide pins - everything is new & pre greased, In my original post I wrote that I replaced brake booster - However it was not the booster but the master cylinder that was replaced.
I should mention that when I bought this blazer the brake reservoir was empty & I am wondering if this could of messed with the abs module - The garage thought the abs was possibly no good, but this was after they changed the brake line, rear calipers & master cylinder they told me when they cracked the brake line at the abs - the brakes released. I thought by cutting all power to abs that it would be out of the equation (I did pull top off abs & resoldered any possible culprits) & also replaced the front calipers, so far nothing seems to work. I am wondering if it's the rubber brake lines or does the abs still play a role even with no power?

 

Hmmm. I can't answer the question about the ABS system with no power but I'd want to think that it would have been designed to go into a state that would allow you to drive the vehicle if the power to it was cut.

BTW, bleeding the brake system on these can be challenging and is best done with an OBD reader that can also activate the ABS system, cycling it, to help get out any trapped air in the system. However, I am at a loss for how trapped air would affect the dragging of the brakes.

That the shop said that when they cracked the brake lines at the ABS, I'm assuming at the exit to the ABS, that the brakes released does sound like that the ABS might be bad.

I'm no expert on the ABS modules themselves so perhaps someone else can jump in. Anyone?

 

Yea from what I understand they cracked the line right at the abs module I know very little about how the abs might react,(that is why I pulled the fuses)but I am assuming this would take it out of the equation, but I just don't know. I'm off to pick up the front brake lines ($45 for both - so why not) and am crossing my fingers, I'll let you know how it goes. Thanks

 

Good luck and let us know what you find out.

 

Wow - so I pull off my pas side brake line, expecting some fluid leakage and nothing - I couldn't believe it, So I pushed on the brake & fluid came out - good, figured I would hook my vac pump to the line and see what happens - it pulled all dirty looking fluid out and clean stuff was coming through so I stopped and it only dripped about once every 5 seconds after unhooking vac pump -meanwhile with the brakeline unhooked (both ends )I try to turn wheel/rotor and no way! I had to get in there with a screwdriver and push the piston back - now I'm wondering if it's possible the new pads are to thick & the piston can't back off enough? So I put an old pad on about 50% wear and will put it back together with new line, bleed & then compare with other side . will update later

 

It sounds like one of the brake pushrods (either the one from the pedal to the booster, or the one between the booster and the master cylinder) may be out of adjustment and not allowing the master cylinder piston to completely release. If that happens, it will not allow fluid to return to the reservoir and, as the fluid heats up, it will trap the pressure in the system.

 

Thanks for the info - I did have the line off of the caliper and with no fluid, no pressure right? I changed back to old caliper, put 1/2 of old pad on and tried it while up on stands - it seems better, drivers side is still to tight so I am going to do the same thing to it, but ran out off time thanks again and will update later

 

Any updates?