'85-'68 Frame Swap - Brakes?

[bluec10]

I'm working at swapping an '85 front suspension into my '68. The '85 proportioning valve has different size lines connecting it to the master cylinder. Why are there different size lines? Do I need to use an '85 master cylinder with these brakes, or can I use an earlier (71/72?) with different sized lines? Thanks for any advice.

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Dream: '68 C-10 Custom with a 396 and a 700R4
Current Reality: '68 C-10, 250, 3 speed, parts in two garages, but lots of hope.

[Fast68Chevy]

85 is metric, try and find a 73-79 parts truck to rob the combo valve off of, you can mount it anywhere you wish to, down on the front V crossmember or at the master cylinder or wherever, just depends on how much line running you want to do.
you can swP the end fittings of the old lines or whatever onto existing or new lines to make them thread into whatever you wish, the fronts are 3/16" and rear is 1/4", all of them years. the fittings sizes are not same on front, from left to right at the hoses inlet ends. use whatever fittings will work, do swapping and re flare the ends(doubleflare)


good luck

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Randy- Lincoln, IL
randy@ccaonline.com 2177353230
*many GM parts bought, traded, or sold -am parting out: '81 Cutlass Supreme Brougham

current fleet: -71 C-10 350/CH465/3.07- basketcase, #1
-90 Cavalier 2.2L sky blue, a driver
-84 Z28 5.0L/700R4/3.73 daily driver
-84 Firebird/SE 2.8L/T-5/3.73/engine bad, project #2
-82 purple Trans Am, project #3
*Paint is overrated*
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[Gee_Emm]

I had done the same conversion you did, I don't remember what Master cylinder I used but I got a brass proportioning valve and mounted it in the frame rail by the pivot point for the shifter then just ran lines up the the master cylinder, it sure cleans things up in the engine compartment that way.

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1969 Chevrolet Custom Camper 20 350/400 70k original miles, 99% rust free, Never winter driven

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[Blue68]

To answer part of your question, disc brakes require different pressure than the drums, thus the smaller brake line to the front calipers.

I swapped in a '75 cross member myself. I've always gone with the 71/72 prop valve and master cylinder. You can get pre-bent lines for these from various sources (just check out Classic Truck mag).

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'68 C-10 LWB, '98 Z-71 350 w/accessories (Serpentine), Edelbrock Performer, Edelbrock 1405 (600cfm) carb, GM HEI, CompCam Extreme 4x4 roller cam, Thorley Headers, Carter Electric Fuel Pump, Vintage Air, 700r4, 3.73, disc brakes and power steering upgrades.


Way too much money and time..But it's a hobby.