The Stovebolt Site Forums The Shop Area The HiPo Shop What size lines for disc/drum set up?

I need to replace the hard line that runs across the front to the soft lines that go to the calipers.

What size should be used on a '51 3100? ...or is stock size ok?

My dual MC came with one 20" piece of 3/16" brake line and one 60" piece of 1/4" brake line which will run from the MC to the split that runs to the wheels. ...it was labeled "universal".

The rubber hoses I got with my kit had 3/8 fittings which are not possible on 1/4 inch lines, so they intended you use 3/16. Since I already had a stainless kit with 1/4 for the front, I just used adapters at the rubber hoses to accomplish this. They DO fit thru the hole, but just barely.

I have mine pretty much figured out after speaking with Van at CPP today. I'm going with the universal 3/16" line from the MC to the front brass T and from the T to the flex lines stock will work because they are larger. With the residual valves in place, once the lines are full, they're full and will always hold the correct pressure. The rear is a no brainer since it's still the original drums.

So your 1/4 lines from one wheel to the other in the front? So the kit comes with 3/8 fittings on the rubber hoses to the calipers, so how are you going to reduce? When I called CPP over this issue, they said the kit was designed for 3/16 across the front, so I had to use adapters. I was kind of taken by this since all of this vintage was stock 1/4 inch lines with 7/16 ends. Not so with this kit.

I don't have the rubber hoses yet, other than what's on there now for the drums. Was actually considering the braided lines. They didn't mention any of the potential issues with fittings.
After looking around a bit I was just thinking about maybe going with a full set of stock lines and hoses then getting an adapter at the MC (if I even need it) for the front MC to brass T line. That way everything matches up for sure. Worst case I have to bend the pre bent stuff a bit to get it to line up with the outlets on the proportioning valve.

Where did you put your residual valves?

I put my residuals at the M/C. If you are going to buy new metal tubing and will have to bend it I strongly suggest looking into buying the copper/nickel tubing. It is a snap to bend. Cost more but worth it. It's the same stuff the "high price spread" cars from Europe use (BMW, Saab, etc.). If your lines need to be pretty then polish it and spray it with a clear rattle can paint. I build streetrods and use it everywhere I can, brakes, fuel, vacuum. It makes for a lot of fun when the unknowing say, "Hey, you can't use copper tubing for a fuel line."

I like the look of that copper/nickel stuff when it's run as fuel and vac lines. Adds a cool steampunkish look, especially when it's coiled as it rises.

Sounds like you have it figured out. When the caliper/rotor kit arrived, it came with hoses but those hoses had 3/8 fittings for 3/16 lines. If you get them elsewhere you may not have that problem. Also, for my taste, the hoses are a bit too short. I would like to have seen them about 2 inches longer.

I have my brakes fully installed, bled and tested now. Everything is working great. Thanks everyone!

So my stock drum brake lines are a 1/4" line from the single MC to a brass T at the frame rail then 3/16" for everything else (rearward to the to a brass L block, into a flex line, into a brass T and across the back axle as well as forward to a brass T and into the flex lines going to the wheels).

Can't tell if it's stock or not and I called a few places and none of them including Inline Tube could tell me what size their stock line and fitting kits are!

SOOO, since the existing line is newer, and it stopped fine with 3/16", and the line that goes into the original rear drums is 3/16", and the new proportioning valve is 3/16" to the front and 1/4" to the rear...I'm just gonna run a 3/16 and a 1/4 line to the frame rail and connect into the existing line using the residual valves as my splices.
...when I get to pulling the cab off for bodywork and frame painting, I'll clean everything up and run a nicer line.

Someone else could chime in if they know for SURE, but most of the trucks I have seen have 1/4" lines with 7/16 ends throughout. The stainless kit I got from the vendors was all 1/4" except for the one piece that runs across the differential.

I am not a hydraulics engineer so I don't know the true ramifications of using smaller line. Wish I did. The proportioning valve in this front disc brake kit has 3/16 (3/8") fittings and so does the rubber hoses to the calipers. I had to use an adapter at the prop valve to keep my 1/4" lines and two more at the rubber hoses. Testing the system today, works really nice the way it is, but is this okay? No idea! I chose to NOT use a booster but it really feels like all four corners are working very nicely.

My disc kit is the same, 3/16" line with 3/8" 24 fittings and I too am not using a booster. My current drum set up is the same line and fittings aside from that first section which is the 1/4" with 7/16" fittings at the MC and that first block. My new residual valves are also 3/8" 24 fittings for a 3/16" line.

I've never had any issues stopping with the current set up even with the mc almost dry it still manages to stop pretty well. lol.