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07-19-2006, 03:05 AM | #1 |
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proportioning valve question
im converting my drums over to discs... is the proportioning valve specific to 71-72 or can i use off say a newer truck i could find at junkyard.... if i cant find one locally ill have to order i guess
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70 longbed 496/th400/Ford 9" |
07-19-2006, 08:12 AM | #2 |
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Re: proportioning valve question
There is a little more to consider -- are you using the 71-72 master cylinder and related lines?
If you look at a 71-72 versus the earlier years, the lines are very different, and I don't think you could just put a 71-72 prop valve into an earlier setup, unless you are going to try to bend some custom lines? The 71-72 master cylinder is much larger as well. The choice for me was easy... I needed all new lines, and a new master cylinder anyway, so I just put all 71 brake hardware on my 68. |
07-19-2006, 09:50 AM | #3 |
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Re: proportioning valve question
A prop valve is technically specific for a particular application. But you MUST have one for disc/drum set up. I can't say for sure, but a newer app (from a c-10) would probably work. Make sure you know the routing of the lines; which outputs go to the front & rear, and make the you know which outputs of the new master cylinder go to the front & rear and route them accordingly.
I've not done one myself, but the easiest way to convert is to change the entire front subframe from a 73-87 c-10. The prop valve is mounted low on the front, main frame crossmember. You should change the master cylinder to a disc/drum type as well, although I'm sure the swap has been done without it. The disc/drum master has different valving in it for disc. A drum type would, in theory, hold pressure on the front brakes.
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'68 50th Anniversery LWB Custom Fleetside, '77 305 v-8, turbo 350, factory speed alert (still works), '71 drivetrain w/front discs. Some call it ugly yellow, others call it Ochre '83 Jeep CJ-7, <80,000 miles, original owner '04 Chevy Suburban, 4x4, 2500, 6.0 ltr, Predator Diablo programmer '95 GMC K1500 Extended cab Last edited by 68speedalert; 07-19-2006 at 09:52 AM. |
07-19-2006, 01:29 PM | #4 |
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Re: proportioning valve question
well i know what all needs to be done to convert it over. i know about the master cylinder. ive bought all the correct equiptment to put the 71-72 spindles on my 70 suspension. i just needed to know about the proportioning valve. my prop valve is RIGHT off of the master cylinder... so i guess one off a newer truck wont work. ill just use all 71-72 parts then.
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70 longbed 496/th400/Ford 9" |
07-19-2006, 01:58 PM | #5 |
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Re: proportioning valve question
You seem to know what to do-
Good luck, I ran into a few things when doing mine. |
07-19-2006, 02:22 PM | #6 |
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Re: proportioning valve question
Would an aftermarket prop valve like from Summit be able to be plumbed in and work too.
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07-19-2006, 11:12 PM | #7 |
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Re: proportioning valve question
I used the aftermarket valve and it works just fine.
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ClusterTruck: 68 C10 Bought in 89, wrecked in 03. Slow low $ rebuild started '17. 6.0 & TKO http://67-72chevytrucks.com/vboard/s...d.php?t=788602 93 K1500 Short Step, 350, NV4500, EBL flash ECU. Vortec heads & roller cam someday... 05 Jeep Wrangler Unlimited. 3” lift & 6-speed 02 E320 the insurance total “free car” 13 Tahoe LTZ |
07-20-2006, 12:06 AM | #8 |
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Re: proportioning valve question
The only difference (externally) that I can tell between the 71/2 and the 73 up is one port that has a line on it on the newer pv is plugged on the older version.
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"If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck" |
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