Upgraded master cylinder, crappy pedal now...

[81_El_Homewrecker]

Hey guys, so I took your advice and upgraded my master cylinder to the larger Blazer master. After bleeding everything and going for a drive the pedal is very hard, and I am not confident in a panic brake situation. I can slam on it and not lock up any of the wheels. I plugged by PCV to try and get a little more vacuum but it’s not a substantial improvement, barely noticeable. I currently have the stock dual diaphragm booster and am thinking about upgrading to the dual B-body booster. Has anyone done this upgrade and seen an improvement between boosters?

P.S. - Engine pulls 15” at idle, not sure what it’s pulling on the booster but the PCV is T’ed into the booster port on the carb.

 

[Max Headroom]

I did a stock replacement once and had the same problem. Turned out to be the rod inside the booster was the wrong length for the new booster. You might want to start there.

 

[81_El_Homewrecker]

I did a stock replacement once and had the same problem. Turned out to be the rod inside the booster was the wrong length for the new booster. You might want to start there.

I have the stock booster on there now, only replaced the master with the larger bore for my disc brakes. I’m thinking the larger dual diaphragm b-body booster might help out.

 

[Max Headroom]

I understand but the booster I replaced, which was called out for my vehicle, had a longer travel than my original. The rod fit but when I hit the breaks, it was like stepping on a rock. Turns out that I needed a rod about half inch longer. Don't remember how I found out but when I put the new rod in everything worked like it was supposed to. Just something to be aware of.

 

[Olgambler84]

I just slapped on the b body booster and man it’s so much better.

 

[TURNA]

Do u have 4 wheel disc?

 

[69hurstolds]

You made sure you didn't trip the combination valve switch during bleeding, right? Sometimes, if this happens, the pedal gets hard as a rock and you only have 1/2 your brakes.

 

[L92 OLDS]

I've been running the dual diaphram B body booster for years now. No issues

 

[GuysMonteSS]

You made sure you didn't trip the combination valve switch during bleeding, right? Sometimes, if this happens, the pedal gets hard as a rock and you only have 1/2 your brakes.

X 2 ^^
I've had this happen.
Had to let it sit overnight to re-set itself.
Guy

 

[TURNA]

I've been running the dual diaphram B body booster for years now. No issues

Part number?