HOW TO: Split the brake lines (many have asked)

[Str8axle]

I should add that a disc/disc master is considerably larger in bowl size than a drum/drum master.
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[ChiefRocka]

Again ... I grabed one from '67 Impala...bolted right up.

The Vette ones are perfect for use with all around discs.

[jocko]

Thanks Str8 and ChiefRocka - picked up my 67 C10 MC this morning. Good to go. Same functionally as the 67 imp mc, just has the clip-held top vice the screw down type. Thanks again for the help!

[jocko]

Hey Chief - reviving this great thread one more time! Quick follow-up for you or anyone that has done this. I noticed that someone asked the question about whether or not the "forward" (i.e. the grill end) port on the master went to the front brakes and the "aft" (i.e. firewall end) port on the master went to the rear brakes. (this is on a DRUM/DRUM setup btw)

Your answer was yes. But I noticed that your fwd line on the master was the one you connected to the rear line's new union. Did that get switched later or something?

Or for anyone out there - on a drum/drum setup, which master cyl port (fwd/aft) goes to which brakes (front/rear), etc....

Thanks all!

[ChiefRocka]

The REAR PORT, closest to the PUSHROD is the main, or "primary" chamber.

This port is for the FRONT brakes....

The FRONT PORT, furthest from the PUSHROD is the secondary chamber....supplying the REAR brakes.

[jocko]

thanks Chief! You Rocka!!!

[ChiefRocka]

Originally Posted by jocko

thanks Chief! You Rocka!!!

[tomfg]

[QUOTE=Chuck78;3307005]
One was a 5/16" to 1/4" adapter, and the other one was 9/16"-18 to 1/4" I think. This fit my new remanufactured 1967 Chevy/GMC truck 1-1/8" bore drum/drum master cylinder. *5/16" tube x 1/4" tube adapter bushing for master rear line (check your master)
*9/16"-18 thread to 1/4" tube adapter bushing for master front line (check your master)
[End Quote]

Having just done this conversion to power brakes on my 64, using a Cardone
Master Cylinder / Booster combo unit, # 50-3715, for a1967 Chevy truck,
I thought I'd mention that for one of the outlet fittings I used on the master
was an....

Edelmann part #265401 (1/4" x 1/2" -20 thread)

and the other outlet port used

Edelmann 258540,
which is described as....
"Use for adapting a 7/16-24 Inverted port to a 5/16" Domestic fuel line.
Female - 1/2-20 Inverted
Male - 7/16-24 Inverted"

Not sure if there's more "correct" fittings, pressure ratings, etc.,
but this is what O'Reilly gave me that worked.

[old cruiser]

http://www.ebay.com.au/itm/Power-bra...65-66-CHROME-/
The system above is what I purchased a few months back as i was piecing together disc conversion as I could afford to. Now thinking of just spliiting lines and keeping drum/drum for a while. Question time, do I need to fit residual valves in the lines near m/c ? I know I,ll need prop valve when I evenyually put discs on front and when that happens would I keep the residual valve connected for rear?
Sorry to enter this thread with these Qs but keeping all break info together may help others.
Cheers Matt

[jocko]

Matt -residual valve and prop valve not required for the dual reservoir drum/drum master cylinder setup. Here's a link that may help, based on Chief Rocka's thread here - http://67-72chevytrucks.com/vboard/s...d.php?t=487384 When you go disk/drum, then you can buy a disk/drum (unequal) dual reservoir master cyl and the prop and residual valve. I'm not certain about whether or not you'll need the residual valve in either setup though - I always thought the res valve was only if you had a "low" mounted master cylinder. With a firewall mount, I do not believe it's necessary - but let's get that confirmed by someone on here. But for the drum/drum - you don't need either as long as the master is on the firewall, that much is correct.

[Rich 5150 69]

Residual valve is only needed when master is down low with the brakes to prevent fluid running back to master....Jocko is correct.

[old cruiser]

Thanks guys, that will make life a litle easier.

[lowmemory]

I did extend our push road for one inch.

Thanks for help!

[JrJc66]

I just finished reading this thread for the the fourth or fifth time. One question i have is, does it make a difference if you split the system front/rear vs front right left rear/ left front,right rear as I believe newer vehicles are?

[jocko]

yes it makes a differenence - do NOT do what you just mentioned. Aft port (closest to the firewall) goes to front brakes, forward port (closest to grille) goes to the rear brakes.

I won't swear by it - but I've never, ever heard of any vehicles, new or old, being plumbed the way you just mentioned. But definitely not correct for these trucks.

Excellent safety question, glad you asked! Big safety implications.

[JrJc66]

Thank you for the quick reply

[ray_mcavoy]

JrJc66, Actually a lot of cars do use a diagonally split braking system like you described. It's very common on front engine, front wheel drive cars. They don't have very much weight over the rear wheels so the rear brakes alone often aren't enough to safely stop the car if the front brakes were to fail. With the diagonally split system, at least one of the front brakes will still be working.

At first, it seems like that would be a good idea for a pick-up truck too since they don't have a lot of weight over the rear wheels either when they're not carrying a load. But from what I understand it's not done (or recommended) because the front suspension/wheel design usually has a positive scrub radius that would cause the truck to pull hard to the outside with only one front brake working. Cars with diagonally split braking systems are all designed with a negative scrub radius so they'll pull to a stop straighter (in theory anyway) with only one front brake working.

[Blue_Aura]

Originally Posted by ChiefRocka

Here's a shot at the R/F tee fitting....Located behind the crossmember under the frame rail:
-
Disconnect the rear line...and plug the tee...then install a union on the rear line....
-
-

Hey John, you used pre-made lengths of brake line, right? What lengths did you use to do the split?

Thanks!

[slepysal]

I used 2 premade line from autozone 1 was about 40" the other was about 60".

[Blue_Aura]

Originally Posted by slepysal

I used 2 premade line from autozone 1 was about 40" the other was about 60".

Thanks. I am just need to get two shorter ones, one from the tee that joins the front and back brakes, and the other at the front left to right tee.

I'll go check Autozone and see how much they are there.

[ChiefRocka]

Originally Posted by Blue_Aura

Hey John, you used pre-made lengths of brake line, right? What lengths did you use to do the split?

Thanks!

Na ... I use new stuff, and flare the ends myself to get an exact fit ...

[Blue_Aura]

Originally Posted by ChiefRocka

Na ... I use new stuff, and flare the ends myself to get an exact fit ...

That's what I originally thought, but then mistook something else that was said. Thanks for the clarification and the awesome write up.
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[hevymetl]

This thread was sent to me when I asked what I should do first on my 66 longbed c10. I agree, safety first. So I have most of the parts and am going to tackle this hopefully Sunday. My question is, do I have to replace the original single line going to the first T? It seems that I just need to add one to attach to the line going to the rear that I remove from the T on the right hand side. Am I missing something?

[LostMy65]

Originally Posted by hevymetl

This thread was sent to me when I asked what I should do first on my 66 longbed c10. I agree, safety first. So I have most of the parts and am going to tackle this hopefully Sunday. My question is, do I have to replace the original single line going to the first T? It seems that I just need to add one to attach to the line going to the rear that I remove from the T on the right hand side. Am I missing something?

You're not missing something.
That's how I did mine.

[hevymetl]

Thanks for the help Lost. Appreciate it.