Bleeding Rear Drums..?

[Vic327]

I see it's a few month old tread but worth mentioning for anyone with this issue. OBS trucks are getting old to the point that some of the rubber brake lines can fail by blocking off flow. It happens from time to time one older cars. You can lock off pressure that causes the brakes to drag or block flow preventing the brakes downstream the hose from working.

 

[Schurkey]

I've had three totally-plugged brake hoses on my personal vehicles. Two front hoses from a '72 Toronado "parts car", and one rear hose on a '68 'Camino.

It is freakin' amazing how much braking power is lost when the rear brakes don't work--and worse in the winter when the rear wheels are still turning under power while the fronts are locked-up.

 

[OffroadZ71]

Reviving my own old thread...still have had no success with getting fluid to the rear drums on this truck.
Have a dumb ? Has anyone tried a reverse pressure bleed throught the wheel cylinder back through the master?

 

[OffroadZ71]

Reviving my own old thread...still have had no success with getting fluid to the rear drums on this truck.
Have a dumb ? Has anyone tried a reverse pressure bleed throught the wheel cylinder back through the master?

I have the Motive pressure bleeder but can't get the damn resivoir lid to seal, so it just pukes fluid everywhere...gonna through some c-clamps on it and see if that works.

 

[Schurkey]

Reviving my own old thread...still have had no success with getting fluid to the rear drums on this truck.

HOW are you bleeding the brakes? Gravity? Vacuum? Pressure? Pump-the-pedal?

I would be very tempted to disconnect the metal tube along the frame-rail from the rear brake hose and see what happens. Plugged hoses have been a problem for me several times.

Have a dumb ? Has anyone tried a reverse pressure bleed throught the wheel cylinder back through the master?

A real disaster for ABS systems. You're pushing the most-contaminated fluid backwards through the ABS unit. The only way this works "good" is to flush the fluid in the normal direction to remove the contamination. Then "reverse" bleed to push air bubbles. Then "final" bleed in the normal direction to eliminate the air bubble in the wheel cylinder between the inlet port and the bleeder screw.

Pain in the asss.

Phoenix Systems sells tools to do this. Couldn't give one to me. And I have little respect for their claims on the web-site.
www.brakebleeder.com/solutions/bleeding-brakes/how-it-works/

How It Works | Reverse Bleeding Your Brakes to Remove More Trapped Air

What is reverse bleeding and how does it work? Phoenix Systems breaks down reverse bleeding process and why it's beneficial to your brake system.

www.brakebleeder.com

 

[Schurkey]

I have the Motive pressure bleeder but can't get the damn resivoir lid to seal, so it just pukes fluid everywhere...gonna through some c-clamps on it and see if that works.

GM (and others) specifically recommend NOT using a pressure bleeder that doesn't separate the fluid from the air used to pressurize the device.

The air pumped into the "garden sprayer" style bleeders tends to contaminate the fluid with the humidity in the air.

 

[OffroadZ71]

Thanks fellas yeah after I thought about my question I realized that I would be pushing crud back through the system.
It has new AC Delco master, rear rubber hose on axle and new cylinders w speed bleeders in it. Will check ABS rear port for fluid then main rear line.... thanks again!

 

[OffroadZ71]

I've used the pedal method, Mityvac, cheap scan tool that does abs bleed..still no fluid starting to wonder if rear ABS valve is stuck closed, would think that would throw an ABS light, but don't have one.

 

[Schurkey]

Have you removed the Speed Bleeders?

 

[OffroadZ71]

Have you removed the Speed Bleeders?

No I havent..should I?