1978 Chevrolet Truck Brake System

Tiny
MJFLORES071578
  • MEMBER
  • 1978 CHEVROLET TRUCK
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
When engine is off brakes are blead good once I turn engine on brake pedal goes all the way to afloor board. Changed booster, brake master cylinder, cylinder on drums, and proportioning valve. Checked for leaks and nothing. Blead the master cylinder alone. Still nothing. Can that happen if the parking cable is not installed and or if the proportioning valve is disc/disc and not disc/drum how its suppose to be?
Tuesday, July 15th, 2014 AT 2:04 PM

2 Replies

Tiny
CJ MEDEVAC II
  • MEMBER
  • 222 POSTS
SNATCH OFF YOUR REAR DRUMS

MANUALLY ADJUST THE SHOES OUTWARD TILL THE DRUMS WILL BARELY GO ON (WITHOUT BANGING THEM ON)

SEE IF THIS RAISES YOUR PEDAL

IF NOT, EXPLAIN YOUR "BLEEDING PROCEDURE" IN MORE DETAIL

THE MEDIC
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Tuesday, July 15th, 2014 AT 4:01 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check to see if the valve is good on the booster where the vacuum goes in. The proportioning valve shold be what the truck has disc drum or disc disc. Same for master cylinder. Also do what cj said.
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Tuesday, July 15th, 2014 AT 4:18 PM

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