89obsSB
I'm Awesome
We have a pressure bleeder that attaches with an adapter to the master cylinder reservoir and forces fluid through. Works perfect everytime
Bleeding Rear Drums..?
- Thread starter OffroadZ71
- Start date
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OffroadZ71
Newbie
Thanks for the pics..what would cause the rear to be blocked off? Im not getting any warning lights on the dash.
In my case it was a mc failure. However that switch moves to the side loosing pressure to kill a leak.. it's designed to give you front brakes only or rear brakes, in the event of a catastrophic failure. If your not getting a dash light then I check at the mc first and make sure you have fluid shooting out of the 1/4 line and follow it until you go to the rear.
I blew a rear line and could not get fluid after the line was replaced. Cracked the line at the MC and had no pressure. Replaced the MC and all bled well. I remember from years ago that a major leak can cause MC piston overtravel scoring the piston seal.
Makes sense with what I exoerienced.
Makes sense with what I exoerienced.
Whenever I took apart my abs unit and removed my mc, it was full of black fluid. It was so black it looked like coca cola or coffee. Keep in mind I just bled the brakes with fresh fluid about a yr to 2 yrs ago. And been keeping an eye on the fluid. Not sure what happened but I think the abs modules stores fluid that doesn't get completely cleaned out.....
Correct. Unless you use a scan tool to chatter the ABS valves, you CANNOT properly bleed the thing. Any air trapped behind closed valves cannot bleed out.
Some folks have luck by driving on a low-traction surface--gravel, snow/ice, etc.---stomping the brake pedal to activate the ABS valves. I guess this "can" work, but then you have to drive back to the shop and bleed that air out of the downstream plumbing and hope it doesn't re-enter the ABS system. Also, you'd have to assure that all channels of the ABS were activated, not just one or two.
This makes sense seeing how you need to chatter the ABS unit to fully bleed the system if air has gotten up that far in the lines. Or you've introduced air up there with line breaking.
I've heard (certainly haven't done it....) that you can activate the abs with the vehicle on stands with some driveline spinning and hard braking. Do so at your own risk in a safe area if you attempt it. Much like the gravel road method of activating it Schurkey alluded to.
it seemed to do the trick when i replaced all the steel lines from ABS to wheels on an S10 blazer I had. May not be the best way and is hard on driveline but a possibility.
