Hello all,

I am having trouble bleeding my 2006 trailblazer LS 4x4 after changing the rear driver side caliper (was stuck out). Put everything together and now I am now unable to bleed the rear brakes (fronts are good). Had rear brakes prior to new caliper being installed. Its as though no fluid is getting to rear calipers, just a few drops.

I have installed a new master cylinder with no change. Also borrowed a Tech 2 computer to try and manually open ABS while bleeding but it would only turn ABS motor on for a few seconds then turn off, nothing felt in brake pedal and still no fluid getting to rear. Tech 2 would not go through the auto bleed procedure.

There is plenty of fresh fluid in resovur, never ran dry and newer ABS sensors on front wheels.

Does this indicate a bad electric brake control module, anti-lock brake modular valve or both EBCM/BPMV ? Seems to me like the ABS valve closed off the rear brakes when I removed that caliper (due to loss of pressure) and now won't open back up. Is there any other ways of getting that valve to release?

Just looking for input or any other ideas before swapping those out. Thank you

 

Also forgot to ask, is a pressure bleeder required to complete the brake bleed to get fluid through the ABS block? Thank you

 

some chevy pickups of that generation have proportioning valves which require a special tool...without this tool you will be unable to bleed the rear brakes.

post a pic of your master cylinder and any square junction blocks

here is what the tool looks like:
scroll down and you'll see it
https://www.autozone.com/repairguide...00c152800a8503