79 Chevy brake problem

TIMSAIDHI

MEMBER
1979 CHEVROLET ASTRO
6 CYL
2WD
MANUAL

79 chevy pickup brakes. I have replaced pads and shoes and master cyl, My problem is the brakes on front seem to not be working right. They do lock up when hard hitting them but have to hit them real hard. The back never locks up. The new master cyl is leaking at the top so cleaned it and still leaks out. Can it be the portion valve is not hooked up right since the front side on the master cyl. Is loosing fluid from the top and the braking problem? Is there someone or a diagram of the portion valve to find if it is hooked up right?

2 Replies

MHPAUTOS

MECHANIC
31,937 POSTS

When you say the master cyl is leaking from the top, is this the filler cap, pipe or what?

Mhpautos)

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Saturday, November 27th, 2010 AT 8:22 PM

MHPAUTOS

MECHANIC
31,937 POSTS

Clean the master cyl down and correct the fluid level ensure that the cap is fitted correctly, press the brakes and have someone open a rear bleeder to check for line pressure, what do you find, just a dribble or good pressure?

Mark mhpautos,

Please respond here and not in the PM as it is to hard to track there.