Still no brakes
Thread Starter
Advanced
Joined: Apr 2016
Posts: 53
Likes: 2
Still no brakes
1974 with PB, IVE REPLACED MASTER CYL, BOOSTER, CALIPERS, EVERYTHING BUT THE PROPORTIONING VALVE. I BELIEVE I HAVE PLENTY OF VACCUM, PEDAL STILL GOES ALMOST TO THE FLOOR AND BRAKES ONLY MARGINALLY WORK. COULD IT BE THE PROP. VALVE? Thx, Bob
Advanced
Joined: Jan 2016
Posts: 84
Likes: 11
From: Yakima Washington State
I do not think its the valve but you must have the bleeder valve pointing straight up when you bleed them or you will leave air to do it i took mine off one at a time and put a block of wood where the disk would go then power bleed them
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
That 'prop' valve is nothing of the kind, it's nothing but a switch that will flip one way or another to ground the wire going to it, indicating a brake failure to the front or rear just an alert to the driver, that's about it....
the electrical part tends to leak and lose pressure capability over time....
just take the rear brake line to the rear of the master cyl. and the introduction of a Tee coupling into the front setup.....green grass type parts at most parts houses.....
THAT made a decent improvement to my stock system, but in fact when hitting the brakes easy heard when in garage with engine idling...a gasp or air the the pedal travel seemed like 6" or so, nearly to the floor and soft as hell even at the bottom of the stroke....
the cure was a Hydro Boost system from a junkyard, a bitch to install but it runs off the power steering system hydraulics for the boost mode, when first driving my '72 after the HB install, Sharkey stood on the nose, and my nose into the wheel.....
Vacuum sux....my car ditched all the vacuum operated accessories....
the electrical part tends to leak and lose pressure capability over time....
just take the rear brake line to the rear of the master cyl. and the introduction of a Tee coupling into the front setup.....green grass type parts at most parts houses.....
THAT made a decent improvement to my stock system, but in fact when hitting the brakes easy heard when in garage with engine idling...a gasp or air the the pedal travel seemed like 6" or so, nearly to the floor and soft as hell even at the bottom of the stroke....
the cure was a Hydro Boost system from a junkyard, a bitch to install but it runs off the power steering system hydraulics for the boost mode, when first driving my '72 after the HB install, Sharkey stood on the nose, and my nose into the wheel.....
Vacuum sux....my car ditched all the vacuum operated accessories....
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
It is common to get air trapped in the system... My advice is to bleed the brakes again and whack the calipers with a hammer while you bleed them. This will help dislodge any air pockets in the caliper.
The valve is just a distribution block... they don't go bad very often...
If the above fails, I can't say it enough.... find a shop with a pressure bleeder and have them bleed the brakes. It'll save you a tone of headache.
Willcox
The valve is just a distribution block... they don't go bad very often...
If the above fails, I can't say it enough.... find a shop with a pressure bleeder and have them bleed the brakes. It'll save you a tone of headache.
Willcox
Pro
Joined: Jul 2014
Posts: 570
Likes: 65
From: Sebastian,FL
I agree with the suggestion on bleeding them again. when I changed my m/c I ended up with average pedal the first go around, i gravity bled them the second time and now they are just as good as my new vehicles. How were the brakes to begin with? Or I guess what made you change all the parts you've changed.
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Melting Slicks
Joined: May 2011
Posts: 2,753
Likes: 119
From: Springfield Missouri
Bleeeeeeeeeeeeeeeed them again, use a clear hose to connect to the bleeder valve, see if air is coming out or just fluid. if it is air, then keep bleeding them. you know the correct order to bleed them don't you??/ also the rears have 2 bleeder vales on each calipar. which one are you opening??? if no fluid comes out, check the MC, bench bleed it again. ever tried to gravity bleed them??/ is the car up on jack stands?? makes the bleeding easier.
