well i did the dics brake conversion. there is a improvement but i really need a new master cylinder, its rusted and the top gasket leaks, surprised it still works. anyway the upgrade says to use a master cylinder from a 76-77 bronco because they came with disc brakes. is it worth making up new brake lines, 76-77 lines are on opposite side, to use the 76-77 master cylinder. i realize that 76-77 had disc brakes but i think the proportioning valve did the work and not the master cylinder. does anyone know if the 76-77 had a bigger bore than the 72.

 

You should be using a MC for disc/drum brakes and a prop valve. I suggest ordering a new MC and brake lines from Wild Horses or your vendor or choice. If you decide to make your own lines just make sure you put the curly-q in them to allow for flex. If you go ahead and get a prop valve (which you should) you're also gonna need a hard line to go from the prop valve to the dist block on the frame.

A quick note about the conversion... If you did the chevy swap make sure you grid your knuckles enough to allow for clearance when the brakes get hot and expand.

As far as the bore size, I don't know the answer to that. I had hydroboost on my last rig and haven't got to the brakes on my current project. I used the heavy duty MC from WH for the conversion. The bore size was correct for my application but I had to put a spacer between the booster and MC because the booster rod was too long causing the brakes to drag.

 

got a rebuilt form checker, it for a 79 F250. it says its for double piton front calipers. seeing as i have 3" pistons in my fronts i figured id go with it. works perfect. might still need a prop. valve but hard to tell seeing as my tires are about as hard as a rock and the streets have a lot of loose dirt on them. but it feels pretty much like they should. ive read where a lot of guys seem to get away with running the stock MC but with my calipers having the 3" pistons, well just not enough fluid to feed them. just nice to have them working again. i have to get 4" extended axle to frame brake lines in the near future so i figured id get the prop. valve then. as for grinding the knuckles, well id already seen that on youtube but good thing to bring up just in case.