Stock vs. adjustable prop valve
- Justin
- Official CCB Member

- Posts: 6199
- Joined: Sat Oct 09, 2010 11:04 pm
Stock vs. adjustable prop valve
I'm starting in on my hydroboost install in the next couple of weeks and am planning on installing a proportioning valve at the same time. I've got discs from a '78 in the front and drums in the rear. I have a stock prop valve from a '76, but realized that I'd probably have to swap out the hard line running from the valve to the rear hose. It may be cheaper and easier to install an adjustable valve between the MC and the H-block. How well do the adjustable valves work in comparison? Are the mainly for fine control, or can they handle larger adjustments if needed?
- ManTruck
- Official CCB Member

- Posts: 200
- Joined: Tue Oct 12, 2010 7:47 am
Re: Stock vs. adjustable prop valve
Just installed one on my sons, XJ. He cannibalized a 72 Bronco for the front D44 and the rear 9" for the Heep. Removed the current set up and removed the ABS which required the adjustable valve. Very good for that use and really helped him out as far as adjust-ability, he did a disc conversion on it also with still the stock shoes in the rear. He had no Prop valve with the ABS setup.
I hope that helps.
I hope that helps.
Owned my 1972 since 1985
Canon City, Co
Canon City, Co
- Gunnibronco
- Official CCB Member

- Posts: 4077
- Joined: Mon Jan 03, 2011 5:07 pm
Re: Stock vs. adjustable prop valve
I'm not sure what it would do without the stock prop valve. Many H-boost trucks end up with too much rear bias, mine did (Mustang h-boost & m/c)-stock h-block & prop valve. I talked to BC Broncos at length about this, they said do 1 of 2 things. Add a prop valve to the rear brake line & "turn them down". Or install the large piston T-bird calipers up front. I did the T-bird calipers and they work great.
"America is at that awkward stage. It's too late to work within the system, but too early to shoot the bastards." ΓÇô Claire Wolfe
74-AWB 98", ZF5, Atlas4, HP609s, ARBs, 37's, 3.5" lift-5.5" front coil springs, Tahoe rear springs, EFI 302, h-boost, 4x4x2 hyrdo assist, custom dash & gauges
72 U15- Explorer Sport-Candyapple Red (1 of 141)
74-AWB 98", ZF5, Atlas4, HP609s, ARBs, 37's, 3.5" lift-5.5" front coil springs, Tahoe rear springs, EFI 302, h-boost, 4x4x2 hyrdo assist, custom dash & gauges
72 U15- Explorer Sport-Candyapple Red (1 of 141)
- akaFrankCastle
- Official CCB Member

- Posts: 4901
- Joined: Wed Oct 27, 2010 5:25 pm
Re: Stock vs. adjustable prop valve
Justin wrote:I'm starting in on my hydroboost install in the next couple of weeks...
I think this is the fourth time I've seen this in the last 18 months!
I've got a lot of room to talk. I've got parts from two years ago on the floor of the garage, just tripping over them.
I think my H block is what is causing my hydro problems. I've got an adjustable on the floor somewhere that I need to install.
Stroppe'd
1972 Sport, 302, 3 speed with old school Duff floor shifter, T shift Dana 20 with JB Fab twin stick, 4.11 gears with Trac-loc, Lincoln hydroboost, Chevy disc conversion, WH gas lift gate shock kit, 33" Duratrac tires on slots and about 2.5" of lift, Stroppe installed: bumper braces, dual shocks on all four corners, GM power steering, trans cooler mount, auto shift column, rollbar.
The Terrible One
1972 Sport uncut, 302, C4 with 1974 column , T shift Dana 20, 3.50 gears w/ limited slip, 1966 U13 Roadster kick panel, and factory power steering.
1973 Stroppe Baja project
1972 Sport, 302, 3 speed with old school Duff floor shifter, T shift Dana 20 with JB Fab twin stick, 4.11 gears with Trac-loc, Lincoln hydroboost, Chevy disc conversion, WH gas lift gate shock kit, 33" Duratrac tires on slots and about 2.5" of lift, Stroppe installed: bumper braces, dual shocks on all four corners, GM power steering, trans cooler mount, auto shift column, rollbar.
The Terrible One
1972 Sport uncut, 302, C4 with 1974 column , T shift Dana 20, 3.50 gears w/ limited slip, 1966 U13 Roadster kick panel, and factory power steering.
1973 Stroppe Baja project