![]() |
Register or Log In To remove these advertisements. |
|
|
![]() |
|
Thread Tools | Display Modes |
![]() |
#1 |
Registered User
![]() Join Date: May 2014
Location: Boring, OR
Posts: 39
|
disc swap 74 into 69 c30
So I'm having a hell of a time finding a backing plate for the 69 drum setup so i'm looking closer at throwing the disc frontend from the 74 I have into the 69. Both are c30's, I think the front of the 74 has the smaller rotor setup on it, the wheels are pretty flat, not dished. Main question is, I have a new 69 master cylinder and brake booster (painted it so I can't return it) and was wondering if I could use it with the disc brake frontend if I used the valve that is in the 74? There is what looks like a proportioning valve on the 69 already right up by the master. The 74 has both sets of lines going right down to the front crossmember to a valve mounted on it. I have also put the rearend from the 74 into the 69. I know i'd be best off to just put the 74 master and booster in, but I'm trying to do this on the cheap. And already have the new master/booster that i'm stuck with. Sorry for the long post. Thanks in advance. I'll try to get pics today
|
![]() |
![]() |
![]() |
#2 |
67-72 parts collector,…
![]() Join Date: Nov 2002
Location: Mid-MO
Posts: 22,699
|
Re: disc swap 74 into 69 c30
Sorry but you need a disc brake master cylinder and prop valve.
The 71-72 version would be a bolt on.
__________________
Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823 |
![]() |
![]() |
![]() |
#3 | |||
Registered User
Join Date: Oct 2013
Location: San Fernando Valley, CA
Posts: 84
|
Re: disc swap 74 into 69 c30
Man I have to type faster, give shorter answers or do less proofreading.
"I missed it by that much" - Maxwell Smart aka Control Agent 86 Quote:
Don't know if the 74 has the vacuum or hydraulic brake booster. If it's a vacuum unit check if the new one you have for the 69 is the same unit as the 74. If it is use the new unit. However, if your 74 has a hydroboost system you may want to consider swapping it over to the 69. The hydroboost system provides better braking over the vacuum booster system. The proportioning valve on the 74 will need to be used, the valve on the 69 is actually a distribution block and won't properly regulate the pressures for the front discs and rear drums. Quote:
Quote:
Are you sure you are stuck with a new master cylinder and brake booster? While they have been painted have they been installed? Have you tried to return them to exchange for the proper parts to do the swap? The worst the parts store could do is say no. But then again they could exchange them for what you need with a store credit. If the parts store won't exchange them you could always sell the new parts albeit at a small loss. But still less of a loss than just sitting on a shelf gathering dust waiting to be used.
__________________
1971 Chevy C30 Custom Camper Cab Chassis Dually 402 TH400 4.10:1 Eaton HO72 1969 Ford Mustang "Mach 1" 428CJ 4 speed "R Code" 1970 Mercury Cougar "Eliminator" 351C-4V C6 1972 Ford Ranchero GT 351C-2V C6 1974 Honda XL-350 Member of the "6 C's and a D" 1-Ton Fun Club! |
|||
![]() |
![]() |
![]() |
#4 |
Registered User
![]() Join Date: May 2014
Location: Boring, OR
Posts: 39
|
Re: disc swap 74 into 69 c30
Bummer, that's kinda what I figured. Just cause I want to do it cheap doesn't mean I don't wanna do it unsafe
![]() |
![]() |
![]() |
![]() |
#5 |
Registered User
![]() Join Date: May 2014
Location: Boring, OR
Posts: 39
|
Re: disc swap 74 into 69 c30
Nice call lolife99. I spent awhile comparing boosters and masters, you're spot on. jb7 brake system, same diaphragm size for the 74 and 72, but with the right mount for the 69, and the 74 and 72 use the same master cylinder. Sucks doing all the work just cause of a backing plate, but obviously it will be easier to find parts for it this way. Thanks guys! Now i'm off to try and move the thing without a rearend in it.
![]() |
![]() |
![]() |
![]() |
Bookmarks |
Thread Tools | |
Display Modes | |
|
|