Brake lone sizing?

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jmlcolorado

Well-known member
Joined
Jul 23, 2010
Messages
1,839
Location
The flat plains of Elbert County, CO
I'm about to start running my brake lines.
I have disks up front with drums in the rear. I took the master cylinder off a 70's Chevy van with the same setup.
The master cylinder has two lines, front and rear. One line is 1/4" and has the smaller reservoir and the other is 3/16" and is on the larger reservoir.

From what I read, the disks should have the larger reservoir since they require more fluid to operate then drums. Is that correct?
Also, I would figure the front brakes would require the larger line.
This master cylinder seems backwards.

Next, i got a wilwod proportioning valve. It has 2 in (front and rear) and 3 out (2 front 1 rear). All ports are 3/16" lines.

How can I change sizes from 1/4" to 3/16"?

The way I'm thinking this should run is this.
1/4" line off master cylinder to the 3/16" input on the prop valve.
I plan on taking 1 line out of the prop valve on the front, using a splitter to split to left and right wheels. Just the line size differences make me wonder [S

The rear is straight forward I think.
3/16" line out of the master cylinder into the 3/16" prop valve. Then 3/16" line out to the back and split to 2 3/16" lines to each wheel.

Am I on the right track?

Here are a couple photos. Sorry for the crappy quality.
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The big line is rear and small line is front. Take the fitting to parts store to match threads to the line size you need.Should be able to plugone of the FO if you dont want to two seperate lines up front.
 

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The big line is rear and small line is front. Take the fitting to parts store to match threads to the line size you need.Should be able to plugone of the FO if you dont want to two seperate lines up front.

Good deal! Thanks guys!

NOW, I messed up apparently. I thought I found a deal on eBay that had 20 48" pieces of stainless steel lines with fittings installed for $40 shipped. I jumped on it and now I'm seeing that you can't double flare stainless without a high $$$ tool :(

Are the lines sold at the auto parts stores stainless?
 
The 1/4 usually goes to a hose. The hose goes to a tee that mounts on the rear axle.from there its usually 3/16 out to the wheel cylinders.
 

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