Power Brake Experts Needed!!!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**DANTIP** · 01-04-2012, 11:32 AM

My recently acquired '72 SWB 4x4 has factory power brakes but my pedal is "hard". My engine vacuum at idle is around 18", the check valve holds vacuum, my calipers aren't frozen-up, the booster looks new, my PCV valve is working properly. I have read some tests for brake boosters and mine seems to pass the test where with the engine off you pump the brakes a few times to use up vacuum, then hold the brake pedal down and start the engine. The pedal does go down a little bit, which should indicate a functional booster.

What am I missing?

01-04-2012, 11:32 AM	#1
DANTIP Registered User Join Date: Sep 2001 Location: Fort Wayne, Indiana, USA Posts: 1,882	Power Brake Experts Needed!!!! My recently acquired '72 SWB 4x4 has factory power brakes but my pedal is "hard". My engine vacuum at idle is around 18", the check valve holds vacuum, my calipers aren't frozen-up, the booster looks new, my PCV valve is working properly. I have read some tests for brake boosters and mine seems to pass the test where with the engine off you pump the brakes a few times to use up vacuum, then hold the brake pedal down and start the engine. The pedal does go down a little bit, which should indicate a functional booster. What am I missing?



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