MASTER CYLINDER PROBLEMIhave
 

I have a 69 camaro and I cant get the original master to bleed the right way, it wont give me a good pedal. I put on a pep boys master on and it works great. I have tried 2 other U.S.302 masters that have all been redone and they dont work. Any help would be great. https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Re: MASTER CYLINDER PROBLEMIhave
 

Are you using silicone brake fluid ?

Re: MASTER CYLINDER PROBLEMIhave
 

No. I was told not to by the person who rebuilt it.

Re: MASTER CYLINDER PROBLEMIhave
 

I'm currently having the same problem with a rebuilt master cylinder I bought for my '69 Camaro....???

Re: MASTER CYLINDER PROBLEMIhave
 

Just out of Curiousity,To the Both of you I ask,Who rebuilt your Master Cylinders?

Re: MASTER CYLINDER PROBLEMIhave
 

Are you bench bleeding them first? You should mount the MC in a well protected vise, install the appropriate sized block off plugs in the brake line outlets to prevent the flow of brake fluid out. Then route two clear hoses from the bleeders back into the resouvoir itself. Loosen the bleeder screws. Fill the res with brake fluid and using a rod or screw driver, push the rear plunger in slowly and watch the air bubbles. Then slowly release to pull in clean fluid. This could take a few dozen times to get all the bubbles out of the internal passages. Push slowly so as not to foam the fluid. Once you get this done, put the lid on and mount the unit in the car. Then remove the outlet plugs, hook up your brake lines to the MC and bleed the entire brake system starting with the wheel that is farthest from the MC first. This should work if your MC is in proper working order to begin with. I would venture a guess that the Pep boys MC did not have the external bleeders that the original GM MC has, and that is one of the reasons why is is much easier to bleed. https://www.yenko.net/ubbthreads/imag...ns/scholar.gif Good luck

Re: MASTER CYLINDER PROBLEMIhave
 

Do you have the correct length rod in the vacumn booster. There is a long rod and short rod depending on the depth of the piston in the rear of the master. Maybe the after market one has a different depth then the original ones and thats why it works ok.

Re: MASTER CYLINDER PROBLEMIhave
 

Good point John and an obvious one to check first...

Re: MASTER CYLINDER PROBLEMIhave
 

Yep---The outfit I had do the rebuild on mine,back when, sent me a shorter rod --had to use the longer rod.

Re: MASTER CYLINDER PROBLEMIhave
 

Bellair,
What's the issue with silicone fluid?