Need More Vacuum For Disc Brakes

[RPJOHNSON2]

I have about 17 lbs of vac. going to the booster from the a 1 port valve from the back of the intake and about the same from a back of the carb. how can i get more vac.Im working on a 72 blazer 4x4 with a/c

[Musclerodz]

What cam is in the motor? What booster do you have? Why do you think you need more vaccum?

Mike

[RPJOHNSON2]

i have a mild street cam size unknown i just put a delco booster on it only showing 18 lbs of vac. the pedal is still going almost to the floor after new brakes and master cylinder and booster

[cparman]

low vacuum problems result in a very hard pedal ( no assist )
not low pedals. I would recheck adjustment at rear brakes, and then rebleed system. 17-18 inches should be enough to make that system work fine

[Huck]

I went crazy for 2 years trying to get my 72 brakes working well. Tried the 3/4 ton booster etc. Then went back to square one--replaced wheel cylinders, calipers, shoes/pads, master cylinder--but the real issue is to bleed the front and rear brakes really well making sure to pull or push the pin in the proportioning valve when you bleed. Once I did that the right way (can't remember to push or pull the pin??)---the brakes work super--will pop you into the windshield if not belted in. My Blazer has a performance Cam with edelbrock intake etc. pushing about 16-18 inches of vacuum. Huck

[RPJOHNSON2]

Thanks For All The Info. I Will Definitely Try That.

Thanks