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B. W. · 03-18-2018, 05:27 PM

If your engine is stock or has a mild cam it should produce enough vacuum.

Measure your vacuum, some say you need 18"hg to work properly but I think 14 or above is good.

If your vacuum reading is low you can temporarily bump up your idle to get better vacuum & test your brakes.

If there is enough vacuum then test your booster, with the key off apply moderate pressure to the pedal, crank the engine with the brake applied, the pedal should drop slightly when the engine starts. If it doesn't drop & you have a rock hard pedal your booster is bad.

(Richard must type faster than me, he beat me to it!)

03-18-2018, 05:27 PM	#3
B. W. Registered User Join Date: Nov 2014 Location: Bigfork, Montana Posts: 1,137	Re: Brake booster question. 72 K10 If your engine is stock or has a mild cam it should produce enough vacuum. Measure your vacuum, some say you need 18"hg to work properly but I think 14 or above is good. If your vacuum reading is low you can temporarily bump up your idle to get better vacuum & test your brakes. If there is enough vacuum then test your booster, with the key off apply moderate pressure to the pedal, crank the engine with the brake applied, the pedal should drop slightly when the engine starts. If it doesn't drop & you have a rock hard pedal your booster is bad. (Richard must type faster than me, he beat me to it!)