73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Brakes and Braking Systems => Topic started by: fbody on May 07, 2010, 08:17:43 am

Title: hard brake pedal, seems no power assist - bad booster?
Post by: fbody on May 07, 2010, 08:17:43 am
Well, when i got the truck, it had what appeared to be no booster assist on the power brakes. I replaced the booster with another (used) from a guy who said it worked fine, but again used part.  I have replaced the master cylinder, bled it first on the bench, no issues.  The brake pedal still requires that I press way too hard to stop the truck.  Pedal doesn't go to the floor or anything.

check valve, that simple? or still is the booster prob and I should buy new.  No leaks anywhere.

73 C20, 3/4 ton.

any thoughts?  thanks.
Title: Re: hard brake pedal, seems no power assist - bad booster?
Post by: VileZambonie on May 07, 2010, 02:10:59 pm
Pump the brake and hold pressure on the pedal. Start the engine. The pedal should drop. -Report
Title: Re: hard brake pedal, seems no power assist - bad booster?
Post by: fbody on May 08, 2010, 11:03:10 am
pedal doesn't drop at all.  pumped it, held it down, started it.. pedal didn't move.  i guess that means booster?
Title: Re: hard brake pedal, seems no power assist - bad booster?
Post by: malibu795 on May 08, 2010, 12:14:39 pm
check vaccum lines from carb to booster -report
Title: Re: hard brake pedal, seems no power assist - bad booster?
Post by: fbody on May 08, 2010, 04:16:28 pm
yep, plenty of vacuum.  pull line, plug it with a bolt, start engine. pull bolt, plenty of vacuum, just about dies.
Title: Re: hard brake pedal, seems no power assist - bad booster?
Post by: VileZambonie on May 08, 2010, 04:57:01 pm
Replace the booster if you have vacuum at the check valve.
Title: Re: hard brake pedal, seems no power assist - bad booster?
Post by: fbody on May 14, 2010, 09:42:01 pm
yep, replaced booster tonight, that was it.  no more rock hard pedal.  Back to power brakes.  thanks again.
Title: Re: hard brake pedal, seems no power assist - bad booster?
Post by: Irish_Alley on May 15, 2010, 12:47:21 am
a question about boosters didn't see the need of adding another post but theres not supposed to be a gaskey between the master cylinder and booster right?
Title: Re: hard brake pedal, seems no power assist - bad booster?
Post by: fbody on May 15, 2010, 09:10:12 am
there wasn't on mine.. and one didn't come w/ the reman booster either.
Title: Re: hard brake pedal, seems no power assist - bad booster?
Post by: Irish_Alley on May 15, 2010, 09:12:37 am
I didn't think so lol mine was sucking in air there so my booster is bad but I got some gasket seal in there for now rigged her right up lol