The Stovebolt Site Forums The Shop Area Driveline Brake line routing ’49 3600

I am converting my 49 3/4 ton to front disc brakes. Bought the kit from TVM everything is installed now it’s time to route the brake lines. Does anyone have any schematics or drawings showing the best brake line routing from the proportioning valve to front and rear brakes? Thanks!

If it helps, stock brake line routing and line lengths are shown in the 29-54 Chevy Master Parts catalog.
Lengths are shown on following pages. The proportioning valve is like the first division block.

Thanks Kevin, I’m specifically looking for routing from the proportioning valve which appears to require separate lines to the left front and right front calipers. With enough time under the truck I can probably figure something out but was hoping I could shortcut my efforts – anyone out there specifically dealt with this issue?

I just finished with the same conversion and just left the existing brake lines in place and only had to hook up one line then to the proportioning valve. Works fine

If your proportioning valve has two outlets for the front brakes, you could plug one of them and just use a single line forward and then split it to the front brakes. That would require a division block, of course. The two front outlets on the valve can also serve that purpose.

Would you have a link to the lit you bought? Thanks

Got my kit from TSM Mfg. Great guy to deal with

Dave,
Thanks for you reply– I am converting from the original single master cylinder to a dual M/C as part of the conversion to front disc brakes, the disc brake kit is from TSM, the dual M/C is from CPP. The truck has 1/4” steel brake lines, same as original. Am facing a couple issues. First, the outlet from the proportioning valve to the rear brakes is 1/2” which is LARGER than the standard for 1/4” brake lines, why I don’t know but I presume I can find some lengths of stock brake lines with a larger fitting and then put a standard 1/4” fitting on the other end and join it with the existing rear brake line. The outlets on the proportioning valve for the front brakes are SMALLER than what is standard for 1/4” brake lines and I will have to use 3/16” brake lines to each of the front brakes ? This set up seems odd to me –- ever seen this ? Is there an issue running 1/4” lines to the rear and 3/16” to the front ? I purchased pre-formed lines from in line tube and now it looks like the lines to the front brakes will have to be custom bent and formed.
Anyone know why the proportioning valve has different size outlets for front and rear brakes neither of which are the same size as the standard 1/4” lines ?

You will be ok with the different size lines front and rear. It is recommended to have a 10 psi residual valve to the rear drum brakes and a 2 psi residual valve to the front disc brakes. Run a short line to each from the proportioning valve with appropriate size fittings which can be purchased at any parts store. From the residual valves you can use adapter fittings to connect to your existing brake lines. When I purchased my kit from TSM they did not have the flex lines at the time so I bought some from Jegs with adapter fittings to fit existing 1/4" lines. Worked perfect so I didn't have to run new lines. You just plug one of those 3/16" ports on the proportioning valve. Good luck. You'll love the disc brakes.

Thanks for your help,I will plug one of the 3/16 ports and pick up adapter fittings so I can use my 1/4” lines front and rear. I read that with my proportioning valve supplemental residual pressure valves are not necessary, that the proportioning valve holds pressure for the rear brakes and also decreases the amount of pressure to the rear brakes to avoid “overwhelming“ them (my words, not mfg.) Your thoughts?

Most of the "proportioning valves" I see advertised are more properly called combination valves as they have metering valve, proportioning valve and failure warning switch all in one unit. I assume that's what you have.

I don't have any additional RPVs in my setup. I have Camaro front disc brakes, Camaro rear drum brakes, Camaro combination valve and Camaro master cylinder. So it's all matched like GM designed and the brakes work great. (note that I have a 1/2 ton)

I see people on this forum adding RPVs. I assume that they have to do this because they are not using matched components and the rear brakes are not doing their share of the work.

You will have to do some testing.

When I did the researching for what was needed there were a lot of discrepancies as to what the proportioning valve actually does. I contacted Master Power Brakes and they said that even with a proportioning valve I will still need the residual valves due to the MC being installed under the floor. Everything works good.

The MC on my truck is mounted below the floor, but it's still above the calipers as the suspension is stock leaf spring and straight axle. The MC has a built in RPV for the rear brakes. That's why I don't need additional RPVs.

Thanks guys ! I appreciate your feedback – going to call CPP tech line and see what they say. Question, why would it matter that the MC is above or below the calipers?

See this thread:
https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=11545

Got it – thanks insomniac !