Snake Oiler

Hey all, I just got another 442, this one a 68 with rear drum and front disc. I bled the front brakes today. I loosened the rear and tried to bleed, but no fluid is coming out. So I bled the master cyl, and it eventually did pump through the bench bleed nipples, then I tried to use an air bleeder on both rear valves, still no fluid. I disconnected rear line from master cylinder and blew air through it. Nothing. I disconnected line ar rear plate and blew air back through towards master cylinder, nothing. Fluid in front is dark but still watery and flows as it should. I am thinking it's the valve on top of the rear punkin that is clogged. Any other opinions? Thanks!

Snake Oiler

Hey all, I just got another 442, this one a 68 with rear drum and front disc. I bled the front brakes today. I loosened the rear and tried to bleed, but no fluid is coming out. So I bled the master cyl, and it eventually did pump through the bench bleed nipples, then I tried to use an air bleeder on both rear valves, still no fluid. I disconnected rear line from master cylinder and blew air through it. Nothing. I disconnected line ar rear plate and blew air back through towards master cylinder, nothing. Fluid in front is dark but still watery and flows as it should. I am thinking it's the valve on top of the rear punkin that is clogged. Any other opinions? Thanks!

66luvr

I have run across 2 things which cause exactly this problem.
1, The rubber line from the rear frame to the top of the rearend housing is collapsed inside and will have to be replaced.
2. If there is a residual valve in the line going to the rear of the car it can go bad or become stopped up and prevent fluid from going the rear brakes. In care you have never ran into a residual valve they are just a small "thing about an inch or two long" which has the metal line coming from the front to this valve connected, and then another metal line coming out of the valve which continues to the rubber line.

That is not a valve on top of the rearend it is a junction block, which may be made onto the rubber line or it may be separate with the rubber line screwing into it.

Snake Oiler

Thanks for info. Is that the proportioning valve we are talking about? That valve has the 2 lines that go to each rear plate.

66luvr

No, it is not a valve at all, it is just a splitter, a "T" it turns the one line coming from the front to the back into two lines, one for each rear plate.
Here is a general diagram of typical brake system, the image on the upper right shows the different things which commonly show up in a brake system. BUT, as it says, not all of the things are found in all brake systems. It shows the residual valve in thee line going to the back. The location they happen to show it is the location I found a residual valve on a 69 Firebird that was bad and stopping fluid from going on to the rear. I removed it and used a brass splicer fitting to eliminate the residual valve and my rear brakes were fine.
But the rear rubber line that goes from the frame to the splitter we keep talking about is where I suggest you look first. Have someone help you, crack the line loose where it enters the rubber line to see if you have fluid pressure/flow there. If you get fluid flow then you can bet the rubber line is stopped up, collapsed inside, preventing fluid getting to the rear brakes. If so replace the line and your problem will disappear.

Diagram;
https://www.google.com/search?q=diag...mPvXSW3XGCwPQi

Snake Oiler

Thank you 66, we will try repairing from the point you mentioned, probably on Friday. Thanks for quick response. Stay well.

Eaton3122

I’m having the same issue in my 71 Cutlass after replacing the power booster and master cylinder. Not sure if the problem existed before or not, but I’m assuming it did. How does your pedal feel? My pedal was very hard before replacing the booster and the brakes would hold tight even when not pressing the pedal. That’s fixed now, but now the pedal seems to travel too far. The car stops, but I’m wondering if the long pedal travel is due to no fluid in the rear? If I can fix that problem, I’m hoping it will make the pedal feel more normal too.

Snake Oiler

So I took off the rear rubber hose that attaches to the brake line on one end, and pumped the brakes. I had a strong stream at the metal line. Then I hooked it back up and undid the 2 metal brake lines from the "T" coupler, and no fluid would go through the T, so I took the rubber hose out and it was perfect on the outside, but solid all throughout the inside and hence the culprit like 66 said above.