Pickwick33

Hi folks, Tracy here.
I have a 2004 Avalanche 1500. I recently had a rear brake line leak and I was in the process of dealing with that. During the time I was moving the truck to a better working area the rearend went out.
I picked up and installed a used rearend, hooked everything back up, replaced the broken brake line and then started the brake bleed process by pumping the pedal and using a catch bottle. I cannot get any fluid to the back brakes at all. Spent a long time trying. I checked for fluid at the front brakes and at the master cylinder ( good at both ), bled the brakes starting at the rear and still nothing, but was able to bleed the fronts.

Any thoughts? Could the ABS module cause an issue that would stop fluid flow?

tech2

some models have a proportioning valve that must be opened with a special tool to allow fluid flow to the rear.
post a pic or video of the lines from the m/c down to the l/f wheel well...that is where it is usually located. you will see a rubber plug and maybe a paper tag on the end of the valve.
this is the welcome section so welcome. put future new topics in the avalanche section.

Pickwick33

I am still learning to navigate on here as far as future topics, but thank you for your response.

Yes indeed there is a proportioning valve, I traced the lines from the m/c down to the proportioning valve and then back to the ABS module.
is there a test I can do without the specialty tool you mentioned to see if that valve is working properly? Or is that tool a necessity?

tech2

OTC Proportioning Valve Depressor for ABS Brake Systems - 7853, Brake Tools: Auto Body Toolmart