I'm having brake issues in the 69. I have a super hard brake pedal. I thought it was a power booster problem but this weekend I started to look at the front rubber brake lines. I took off both sides and they are ok, checked the steel lines and they look great, no blockage. I went to bleed the whole system starting at the back and initially I had a small amount of fluid coming through both sides. I went to the front and they bled fine. I thought the porportioning valve on the frame rail was bad so I took off the line before the valve to see if it was plugged and it is fine. Now with that line off I apply the brakes and there is no fluid at all coming from that disconnected line. I haven't checked the other metering valve under the master cylinder. Is there someone that sells rebuild kit for these porportioning valves or is there something else I'm missing?
I believe you need to reset your brake proportioning valve and can follow the procedure below:
https://www.speedwaymotors.com/the-toolbox/brake-proportioning-valve-reset-symptoms-bleeders-adjustment/134183?srsltid=AfmBOoqrD3S5V8Sf40iceRtk3rkoKzG_eIgxzjUVJDV7E-8cmT8rvChs
As for having an issue with brake pedal effort, I would check your brake vacuum hose and the check valve which goes into the brake booster.
I would think the rear brake rubber line could be the culprit.
I checked the brake pressure differential valve and it didn't need reset but I ended up rebuilding that valve and also rebuilt my proportioning valve under the driver's side frame rail, the only valve I didn't touch was the metering valve
I took off the master cylinder and bench bled it. With everything reinstalled I still have no fluid at the rear brakes. I took off the line just before the proportioning valve under the car and no fluid. I'm not sure what could be wrong, any tips or advice would be greatly appreciated
Have you checked the metering block under the master cylinder with the rear line disconnected?
David are you talking about the brake pressure differential valve that's under the master cylinder? I did take the rear line off of that and no fluid came out, and then I took the front line off and fluid came out of that one. I'm wondering if it might be a master cylinder issue.I haven't touched the metering valve yet.
Well, call me forgetful for not using the correct terms for these parts. Let's try this.
https://camaros.org/brakevalve.shtml
There is a kit for the metering valve with the big nut on the front. I rebuilt mine. Sorry about the link pointing to the wrong kit but you can go there and click around to find the right kit.
https://www.musclecarresearch.com/gm-1233464-rebuild
Quote from: Stingr69 on August 14, 2026, 09:16:38 AMThere is a kit for the metering valve with the big nut on the front. I rebuilt mine. Sorry about the link pointing to the wrong kit but you can go there and click around to find the right kit.
https://www.musclecarresearch.com/gm-1233464-rebuild
Unless Muscle Car Research changed their design, don't buy it from them. Many have failed....Joe
Well, if no fluid came out of it after taking off the steel line, id be willing to bet thats your issue.
Send it to Mike Gibbons. He has some new kits that are working....Joe
Seems you had a similar brake issue back in 2012. How did you resolve the problem?
https://www.camaros.org/forum/index.php?topic=9424.msg67919#msg67919
I did eventually get fluid to the rear wheel cylinder, wow can't believe that was 14 years ago. This time around I found the rear rubber hose is plugged.
I had a similar problem on my 69 SS. A hard pedal for brakes that worked ok until you really tried to stop quickly . Most all parts were new by a previous onwner. The booster held vacuum and the valve worked although I replaced it. I bled everything the old way (pedal pumping) but finally I replaced the booster and cured it all. It was a repop by the way.
Well, I get to be right every once in a while-reply #2. The hose typically fails internally and just blocks off all fluid flow. Is all good?