78 power brakes on the 67??

[67chevemall]

So I have a new mastercylinder/booster, and port. valve from my 78
that I parted.
Buddy told me that I could make the 67 power brakes with these parts.
Which is easier than going to disc.
He says it will bolt right up? Might have to adj. the lenght of the rod going
to the pedal asm.

Has anybody done this? Would it work and can the drum brakes handle
the power assist???

Cheers

[MDC]

Not sure about the 78, but I believe it will. I put one from a 71-72 on my 67. Used my MC and prop valve. Works great, you won't believe the difference. Best two hours spent so far, and I am slow.
There is a thread somewhere, I'll try to find it.
MDC

[MDC]

http://67-72chevytrucks.com/vboard/s...d.php?t=163387

There you go. Nice write up by Farside

[67chevemall]

nice! That MC looks like a 67-72
The 78 is big and round, not sure if it will work.

[john]

I wouldn't use the disc m/c and valve on drum brakes. Booster should work with right rod. John

[Robert1970C20rstbukt]

Get a dual diaphragm booster from a one ton truck. My 3/4 ton originally had a single diaphragm booster and I replaced it with a dual from a 1972 GMC 3500, it made a huge difference in stopping power.

[Tx Firefighter]

I'm also running a 1 ton booster on my 72 truck. They do stop well that way.

[pa_snowman]

can anyone tell me what all year boosters and mounting brackets will fit on a 67-72 truck? is it only this year group or will others work?

[dennislbrooks]

http://67-72chevytrucks.com/vboard/s...d.php?t=182807

[dennislbrooks]

couple of pics of a 79 C10 booster for a 67-72

[67chevemall]

^ that is close to what I have. Mine is a 78 C 20 booster and MC.

Are you bolting that up to drum brakes?

[dennislbrooks]

you could, just re-use your stock splitter block--do not use a later model proportioning valve--the 79 booster above was modified for the firewall mount.

[pa_snowman]

how/ what was modified and why?

[dennislbrooks]

well, besides all the holes not aligning, the 73 up will mount at an angle on the 72 and down firewalls. The master cylinder will not be level. If/when you remove your oem master cylinder , do a trial fit and you will see the differences. If you have stock column shifting you may also run into interfence with the 73 up vacuum booster.

[dennislbrooks]

here are a couple of more pics. The gray one is a modified 79 with a 79 master cylinder on it. The black one is an modified 84 Fiero -- takes the alumnum 1 1/8" bore master cylinder setiing beside it. Both have been modified for use on a 67-72.

[67chevemall]

^ cool the fierro one looks interesting...

[67ChevyRedneck]

Not sure how the later model prop valves work, but drum brake trucks use MC's with equal reserviors. Equal brake pressure (as far as I know) goes to the front of the truck and to the rear. A disk MC has a larger front reservior and sends more braking power to the front and less to the rear (to keep the rears from locking). I think using a disk MC on your drum brakes would cause your front brakes to lock VERY easily. Not sure if you could use the booster...

[dennislbrooks]

There are many possibilities and if you know of drawbacks please say so. But if you want to go to the newer aluminum master cylinder with a more compact vaccum booster --this modified 84-86 Fiero is a nice package. MC fittings are the same. If you run disc/drums -- you will need a proportioning valve---if you run alll drums--just use your stock splitter block. If you run disc all around-- run no like drums all around or an adjustable proportioning valve. I completed this one last nite for 67-72 --may even work on a 65/66.

[pa_snowman]

why can't you use the stock 67-72 master cyclinder on the fiero booster

[dennislbrooks]

The Fiero booster has a short rod --- I believe the 67-72 master cylider has an inset for the booster rod touch--- there probably is one that would work if you do not like aluminum --like a 79. Or the inset hole could be plugged.