Single to Dual Res Master Cylinder Conversion

[jocko]

First of all - a big thank you to Chief Rocka for his great write-up on how to do this ("splitting the lines"), it helped me a lot, as did Chief in a few PMs (Thanks Chief).

After surviving my new T5's test drive, the brakes locked up as I pulled into my driveway (quite fortunate, actually... If they're gonna lock up, there's no better place than where you're gonna park it anyway).

So, had been mulling over a disk swap or a power drum/drum setup, but in then end, I just wanted to get this thing back on the road. Spent most of the summer on blocks for the T5 swap which is finally done. I had the correct non-power 67 C10 dual master laying around and the brake lines, so I just went for it. I still may add a booster, I have the good Captain's bracket already, but will need to purchase a new master and booster for that setup. I had a booster that would work, but bought the wrong master (i.e. a non-power, deep bore rod-piston master - the one in these pics...)

Also, on a side note, I was itching to try out my Speedomotive (I think it was anyway) pressure bleeder so I could avoid pestering all my neighbors with the bleeding process.... In the end, the neighbor had to come over to pump the brakes and the pressure bleeder ended up in the garbage - that turd would NOT seal to the master worth a darn especially with the cheesy chain link holding system it has, but it also didn't work with giant c-clamps. Or, worse yet, it WOULD seal, then let go when you least expect it. That's the danger with these pressure bleeders - if it even "thinks" about leaking, it's gonna be catastrophic under 15 psi - fluid EVERYwhere. I took TWO, yes TWO DOT 3 brake fluid showers that day.... Glad I got that itch out of my system - from now on, I'll just pester the neighbors, thank you.

Anyhoo, I'm safer with the dual res master at least. Braking perf is good, but really no better than with the single pot master - but that's what I expected - just switching to a same bore dia dual res master really shouldn't improve performance relative to a functioning single res, just adds safety. But it looks a little nicer I think. Learned a lot - probably bent each brake line twice to get it right, but hey, that's part of the fun.

Thanks again Chief - your thread gave me the idea how to do this. And by the way, since going from a non-power single res master cyl to a non-power dual res master cyl and both had the same depth rod hole - no adjustment was required for the push rod. Sweet! So now she's on the road again, and all I have left to fix is a squeaky speedo cable, a little more bleeding, grease the pedals. Oh yeah, and rebuild the motor. But that's another day.

Here's some pics (and I discovered that my firewall was originally that champagne/fawn/thingy color in the process. Cool!)

[pdxhall]

Good job Jocko, the lines look great and I agree, the dual master looks better and you've added an element of safety to your truck.

[T Smith]

Nice bending, you did a fine job, looks great!

[likaroc13]

i agree, nice work!

[old cruiser]

Looks good, gotta do mine one day

[boucher racing]

Looks Great.

[markeb01]

Excellent, both cosmetically and functionally.

[HEI451]

I single person manual gravity bleed these masters on the vehicle, not so hard to do if you haven't broken the system open at the wheel cylinders.

As with any fluid, air travels upward in them. Knowing this, I remove the master from the pedal and firewall, and tilt it forward, rear of cylinder higher than the front, and gently push the push rod into it until all air is bled out of the bleeder ports in the reservoir, done. Having the bleed port(s) higher than the rest of the master bore ensures the air travels out those ports, fully filling the bore, and lines. When I replaced the master on my C30 some months ago, I did the one person pump bleed above, worked well, but, I didn't have to open any lines past the master to line fitting, and, when I did the power booster and same drum master, did the same procedure, single person gravity bleed, no problems.

Gravity is a lot easier to work with, then pulling the air downward to, through, and out the wheel cylinders, if conditions are favorable.

If the system has been broken open at the wheel cylinders, I do recommend either the full manual two person method, or the power bleeder method.

If you still have that power bleeder in your trash, I'd like to have it, will pay shipping to Northern Nevada, will make something useful out of it.

[hopped up]

maybe i missed it, but what dual master works on our trucks? i have a 64.
Posted via Mobile Device

[jchav62]

Beautiful work!! Where can I find Chief's write up?

[jchav62]

Originally Posted by hopped up

maybe i missed it, but what dual master works on our trucks? i have a 64.
Posted via Mobile Device

67 C10 dual master (drum/drum)

[jocko]

Originally Posted by jchav62

Beautiful work!! Where can I find Chief's write up?

here ya go! http://67-72chevytrucks.com/vboard/s...d.php?t=332148

[jocko]

Originally Posted by HEI451

I single person manual gravity bleed these masters on the vehicle, not so hard to do if you haven't broken the system open at the wheel cylinders.

As with any fluid, air travels upward in them. Knowing this, I remove the master from the pedal and firewall, and tilt it forward, rear of cylinder higher than the front, and gently push the push rod into it until all air is bled out of the bleeder ports in the reservoir, done. Having the bleed port(s) higher than the rest of the master bore ensures the air travels out those ports, fully filling the bore, and lines. When I replaced the master on my C30 some months ago, I did the one person pump bleed above, worked well, but, I didn't have to open any lines past the master to line fitting, and, when I did the power booster and same drum master, did the same procedure, single person gravity bleed, no problems.

Gravity is a lot easier to work with, then pulling the air downward to, through, and out the wheel cylinders, if conditions are favorable.

If the system has been broken open at the wheel cylinders, I do recommend either the full manual two person method, or the power bleeder method.

If you still have that power bleeder in your trash, I'd like to have it, will pay shipping to Northern Nevada, will make something useful out of it.

No problems bleeding the master, did that on the bench. But had to bleed whole system via wheel cyls since it was broken open and lots of air introduced. I'm actually gonna hang onto the bleeder - most of it still useful, but yikes was it frustrating!

[KroAutomotiveInc]

who needs breaks lol

[Rich 5150 69]

Good job Jocko...loos great.

[Str8axle]

Nice, clean install. Your lines look great. I've seen some crappy brake line routing/installations in my day. Yours is A+. You ever work in a brake shop? LOL!!!!

[jocko]

Ha! Nope, but I feel like I have now... It was kinda odd - first set of lines I bent weren't much different, but I wasn't satisfied with them so started all over. The second set took about 1/3 the time and came out a little better. Enough at least for me to be satisfied with em. My brake fluid explosion from the pressure bleeder actually ate paint off the frame where it dripped - nasty stuff, my hands are still sore where it got into some cuts! Luckily, I got it wiped off the firewall in time to salvage the mini-paint job.

[hopped up]

Thanks jchav
Posted via Mobile Device

[ol_skool_chevy]

nice work...I see you used a 1967 Drum drum. BUT did you have to change your lines? can i use my old lines? maybe I missed as to why you did lines also...

OPPS i see now why...stupid me...dual lines

[jocko]

ol skool - you can actually re-use the original line if you want (really worth reading Cheif Rocka's thread, embedded in here somewhere). Although he bent 2 new lines also - you could use the original line and add only one as long as you cap the tee and add the union in the right place, etc. But if you look at my one little spaghetti-lookin brake line in the first pic, you'll quickly see why I wanted to bend 2 new ones, woulda looked kinda silly I think becasue that original line just screamed sad.

[ChiefRocka]

Good Job Jocko !!!

Nice and clean work on the bends...

I'm gonna have to visit my thread again soon for my current truck !!

[jocko]

HEY thanks Chief, nice to hear from you! You get all the credit on this project! Thanks so much for your help and the splittin the lines thread you made a while back.

[ol_skool_chevy]

Is there any real Benefit to running a brake proportioning valve with Drum/Drum?

[Rich 5150 69]

It would still keep the front wheels from locking up in a panic..but then again it was designed for disc/drum ...may or may not.

[protrash64]

Nice job jocko......going across the x-member always seems to be the hardest part to me.