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master cylinder ?

bobtail

Sr. Member
Joined
Apr 3, 2013
Messages
365
Loc.
high in the desert
I converted to front disc brakes now my master cylinder leaks into the cab. I want to replace the master cylinder which one should I buy? I don't have a power booster. The one I have now has two compartments one larger than the other. is there a rebuild kit? or should I buy a new one.
 

bronconut73

Bronco Guru
Joined
Aug 7, 2012
Messages
9,916
Hit the parts store for a standard disc brake mc.
Like a '76 eb with manual disc.
I use a '73 F-250 camper special manual front disc with dual piston calipers master cylinder.
It's a tight fit but it works great. Best part is it's only $18 bucks at Autozone.
The easier thing would be to get the '76 mc mentioned above.
 

Crude dude

Jr. Member
Joined
Feb 4, 2012
Messages
136
Not sure how it compares to the master cylinders already mentioned but I installed an 84 Dodge Ramcharger master cylinder and it works really good. All you have to do is drill the two mounting holes out to 3/8" and its a perfect fit to mount. You will also need to go to a parts house and pick up 2 adapters for the brake lines, different threads.
 

Apogee

Contributor
Bronco Guru
Joined
Nov 26, 2005
Messages
6,033
The Ramcharger MC is a 1.125" bore unit with 1/2-20 and 9/16-18 inverted flare outlet ports, cast aluminum body and shared plastic reservoir with screw-on caps. There are similar variants of that Mopar MC in 1.06", .94" and .88" bore sizes that I know about (different outlet port sizes on some), and probably others as well.

There seems to be some confusion as to what a "Camper Special" unit actually is...at least on my end. If I'm not mistaken, the manual/power brake unit from the F250 with single-piston calipers is a 1" bore and would therefore match the 76-77 EB unit in terms of bore size and performance, making it the better choice. The power brake F250 unit for 2-piston calipers has a 1.25" bore size and I think was only supplied in power configurations, way too big for stock Ford or Chevy single-piston caliper setups IMHO unless you're running hydroboost or correspondingly large vacuum booster and have the gain to push it.

Reservoir size can indicate whether the MC was designed for disc or drum, however is not definitive and has little to nothing to do with how the hydraulics actually perform since the added volume in a disc application (versus a drum application) is just there to account for pad wear over time. Bore size is what determines the pressure output for a given input force at the pedal while stroke is determined by the volumetric requirements of the calipers and pedal ratio.
 
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