Based on the comments within the provided link above if I am interpreting things correctly I CAN use my 1986 Disk drum master with no problems because ......... The master in the picture is for "drum disc", the drum side is the small side. So if you want to use it for "drum drum", it should work fine, plenty of volume.

The problem would be if you wanted to use a "drum drum" master to do "drum disc" brakes, there will not be enough volume for the disc.............

I am a bit confused because on another board in which I have posted the same questions too a member said this within his comments ...............Additionally, the 86 master is for disks up front which use very little fluid to actuate compared to drums...............I am as I am sure you have all guessed using the stock drum drum set-up, Thanks again for all the great input, Ill get this truck back on the road yet with all of your help!

 

I am searching on-line and I can see now that a residual valve and a proportioning valve are clearly not the same. I guess I am finally now starting to figure out why my brakes just plain stunk! Just plain didnt know what I was doing the first time, hopefully that wont happen again

 

Sorry I've been off-line, but it sounds like you've got it figured out. You shouldn't need a proportioning valve, but you do need residual valves, ones with the ratings for drum brakes. Your MC may have one in the drum port already.

 

Thats why the old mustang drum/drum dual MC is a good choice . It has residual valves in both ports .

 

Can mayby add a little here. I did my 54 f-750 brake system over.

Here is what I found. and did

 

excuse, fat fingers on the type,
54 f-750
Ran all new lines
rebuilt all wheel cylinders. ( 6 )
rebuilt master
Sent my original boster under the frame ( 10 in type) out for rebuild.. This has to be bled out also.
What I understood at the time, with the 6 wheel cylinders, is that you are moving a lot of fluid. After some bleeding and adjustments, brakes are great.

When I was first bleeding, I got to a point where they would not bleed any more and make a difference. I still had a similar problem as yours. the rest of the pedal slak was taken up with adj the brakes. You could possible have over sized drums by now and the brakes are traveling more then normal to fill the gap.

the second part of the problem was the wheel cylinders were larger then what the parts book called for. they use to do that on some trucks, if they were heavy duty use. I wound up putting plungers that were the next size larger.


Hope this helps

JimG 1098

 

Prob. a nieve question but will the old mustang ( approx year ? ) bolt directly onto my 1986 power brake booster. I guess what I am asking is are the spacing pretty consistent in size?

 

Thanks for that, unfortunately when I purchased the truck it was in boxes with many pieces missing so I do not have any of the original stuff.

 

I used an outfit out west that rebuilds them, but he actually had the exact one I needed. If you need his number, let me know. Did a great job. They were comon on a lot of trucks, back in the day

 

C7ZZ-2140-G .. Master Cylinder-Use with Power Drum Brakes / 1967/70 Mustang/Cougar.

 

Couldn't say for a fact, but AutoZone normally stocks the Mustang MC, so take yours in to match. More than the hole spacing needs to match, the hole in the booster has to match up with the spigot on the MC.

 

I guess I am getting a lesson on brakes. evidently the original master cylinder ( 1952 F-7 ) used a piston bore diam of 1.5 inch, talking with a so-called brake expert ( dont want to say what company ) he says that I need to find a master with same bore diam.

This is proving to be impossible in finding one that will bolt directly onto my 1986 F-250 brake booster. Ford just did not use one this large on these later trucks with this booster and remember the booster has to work with my 1986 F-250 pedal assy that is already installed and is NOT going anywhere considering the amount of time I have in to make all of that work!

I am and have ordered a master cylinder that was originally intended for ( if I remember correctly ) 68 - 76 F-350 with a piston bore diam of 1 1/4, this I am told will bolt directly onto my booster.

I have to replace the booster anyway so I have also ordered a booster/master assy that was originally intended for a 1986 F-350 that should bolt directly to my pedal assy with no modifications. The piston bore diam of that master though is 1 1/8 .

The original 86 F-250 master that I was using had a piston bore diam of 1 inch.

I dont know wether this guy ( brake expert ) is making a mountain out of an anthill.

Maybe he is being overly ****, I understand that brakes dont want to be fooled with but the truck stopped fine with the 1 ich bore master cylinder that I have been using, the problem was or has been noted above.

Consider I dont have alot of choices I have to make a choice I guess and roll the dice and see if one of these larger masters along with two 10 pd residual valves will fix the problem.

 

When I was cobbling together my brake system I ended up with a Ford Focus booster and a Cadillac MC.....nope, they didn't line up. the mounting studs on the booster were a little wider than the hole spacing on the MC. In typical farm boy fashion I elongated the holes in the MC slightly and bolted it together.

Sometimes you just have to make things fit....lol

Bobby

 

Im not apposed to a little cobbling but would like to do the best I can at it first

 

I understand

I've never messed with the braking system on the larger trucks. I wish you luck on it

Bobby