Hello,
I recently put E34 big brakes on my car along with SS brake lines. 3 of the brakes bled fine, but the rear drivers side brake did not. There wasnt really any fluid coming out. And I noticed that my power steering reservoir overflowed.
Im thinking that maybe I have a debris or some sort of obstruction in that one line. I had thought I would disconnect these two hardline connection points and blow compressed air through to see if I get air coming out the other side. But those nuts on the brake line are pretty soft and even with flanged wrenches they put up a fight and want to get buggered up. So before I take these apart I thought I should check my logic here.
I disconnected those two copper colored brake line circuit "junctions" and blew some compressed air through them. Seems to have worked. Hope to button this back up tomorrow and test.
No joy.
Does the ABS have a separate circuit for the right and left rear brake or do they share a line that splits somewhere downstream of the master cylinder ?
EDIT: Yes, it does.
Last edited by DavidE9 on Feb 23, 2025 6:05 PM, edited 1 time in total.
Forgive me if this is a stupid idea, but what I would try is to bleed with the engine running. Utilize that hydroboost to build some extra pressure in the system. If there is a blockage that should help get things flowing. The master cylinder should generate lots of motivation with the booster involved.
turbodan wrote: Feb 23, 2025 2:34 PM
Forgive me if this is a stupid idea, but what I would try is to bleed with the engine running. Utilize that hydroboost to build some extra pressure in the system. If there is a blockage that should help get things flowing. The master cylinder should generate lots of motivation with the booster involved.
Even without the hydroboost you can generate a lot more pressure out of the brake pedal than compressed air.
Am I correct in understanding that if I pull the relay from the ABS (as discussed below), I should still have pressure to all four corners, just no actual ABS ?
"If the ABS is deactivated the system simply acts like extra long brake lines. There's no degradation of standard braking if the ABS is offline."
I'd guess your issue is in your ABS unit but don't have any advice to offer on that. Maybe there is a way to cycle the valves.
Just a data point as I have a pressure sensor in the line going to my front brakes (no ABS), I can generate about 1500 PSI standing on the pedal with the booster.
DavidE9 wrote: Feb 26, 2025 5:55 PM
Am I correct in understanding that if I pull the relay from the ABS (as discussed below), I should still have pressure to all four corners, just no actual ABS ?
"If the ABS is deactivated the system simply acts like extra long brake lines. There's no degradation of standard braking if the ABS is offline."
I've been driving my 88 like that for two years. ABS only gets involved when lockup is detected, it plays no role in the functioning of the brakes up to that point.
"Forgive me if this is a stupid idea, but what I would try is to bleed with the engine running. Utilize that hydroboost to build some extra pressure in the system. If there is a blockage that should help get things flowing. The master cylinder should generate lots of motivation with the booster involved."
