Master Cylinders

[bmcgc]

Ive done alot of surfing the past month looking at the various ways that people have repaired/replaced/upgraded their Slicks.

I see on the full size Bronco forums that 78-79 owners are going to the F350 dual diaphragm brake booster, F350 MC, F350 rear cylinders. 78-79 T-bird dual piston calipers. They say that braking is vastly improved. All bolt on, no mods required, under $400. It sounds like that would be the way to go for someone who is starting with a 4 drum setup.

What I have not been able to determine is if the 87+ plastic MC will adapt to our trucks.

Since Im getting ready to do the brake swap, I think I will go to the p-n-p and grab one and see if I can make it work. They used them on F150s with disc/drum 87-96. The mounting holes line up. Im pretty sure the fittings are metric, but I will grab the MC lines with it.

Those are so clean and compact, no rust or leaking cap either.

I have a 78 brake booster bracket. Its the same $ to go the F350 route as the F100 route.

Opinions?

[cavinandpavin]

i just put all 74 disk stuff under mine and it stops very well. no booster
i found a 74 with new rotors calipers and pads at the yard and got all but the master and i got it new. (i beams and all ) it was an easy swap (mines a 65)

[jaythejug]

I have disc brakes on the front. I have no idea what the previous owner installed. I think it is one of the conversion kits though. thier powered by the original master cylinder with no booster. They work great. But, i just found a leak behind the pedal. do you think i should install an updated master cylinder or just go with the stock and rebuild it?

[cavinandpavin]

Good time to upgrade to a dual resvior master. I don't trust a single myself, you loose a rubber brake hose and ALL your brakes are gone

[bmcgc]

Jay, the easy way for you is to replace the MC, its less than $20.

Hands down the dual MC is safer, but on the other hand these trucks have been running the single pot MC for over 45 years.

[bmcgc]

Double post

[Toyz]

Jay, the easy way for you is to replace the MC, its less than $20.

Hands down the dual MC is safer, but on the other hand these trucks have been running the single pot MC for over 45 years.

Good point, 45 y.o. truck, even with new brake lines,; things can, and do, fatigue. If that "thing" happens to be a rear shock mount, and the newly freed shock just happens to take out a brake line, you MIGHT want to start practicing your handbrake stops!
Paul

[Hawkrod]

Just a minor point in this thread, 78-79 Tbirds never had dual piston brake calipers, they are all single piston. Also, the F350 booster is hard to get and most guys are using the F250 and think they have the F350 booster(I will try and post some pics today of both as I have the F350 booster on my CrewCab and F250 boosters on everything else I own!). To get a rebuilt F350 booster you almost always have to have a core as they are so uncommon that they send yours out to be rebuilt. Hawkrod

(edited)Pictures as promised. Sorry for the dirt but these are in long term storage! You will note that the F350 booster is larger in diameter and it is longer with the master cylinder face almost flat with the front of the booster while the F250 mounting area sticks out on the front of the booster. The F350 booster also has the extra support on the booster. The big F350 boosters are rare and even most trucks in the junkyard don't have the big booster. The F250 booster is plenty fine for 99% of teh vehicles out there and unless you have a source I would stick with that. Also note that the F250 booster also comes in a linkage style booster that is super easy to adapt to earlier trucks because the pushrod is a flat bar with two holes in it. Very easy to make your own the right length. I do have a few F250 booster cores with brackets if anybody is looking for one. Hawkrod

Pictures:
F250 dual diaphragm booster:


F350 dual diaphragm booster:

[bmcgc]

I think Im going with the 66 booster and the 87 MC. All will bolt up just fine.

Ive got a couple other irons in the fire so it will be a week or two before I get back to brakes.

[BigMike]

This is the setup that I was on my truck when I got it. The MC that was on it leaked from the lid. I installed a new MC and while not as bad, this one too leaked from the front reservoir part of the lid. I got yet a 3rd MC and it did the same thing. I bench bled both of the new ones and there was always pressure squirting up from the front reservoir. I took the new MC back and got a refund. I reinstalled the first new MC and just can't get the damn thing sealed up and it's dripping onto my newly painted frame.

I got so fed up with the whole thing, I bought a new booster and MC of ebay for $167. It uses a Corvette style MC. I'm going to install it tomorrow.

Sorry for the thread jack, good luck with your install. I just had to vent.