Slick 60's

Okay so I swapped out the old fruit jar M/C with a '68 Mustang non-power disc/drum M/C a year or so ago and now its sticking, most likely due to the truck not being driven enough. I called the parts store to get another one and they're not showing a non-power disc drum, only a power disc drum M/C. Can I use this M/C or do I need the non-power type?

before you go buy an mc best to check if the calipers are sticking.

I cracked the line at the M/C and the brakes released. Wouldn't that indicate M/C?

could be adjustment of the eccentric bolt that holds the mc rod to the brake pedal.
there should be a little movement of the pedal before the rod pushes on the mc piston.
if its too tight the mc wont fully release.

Disregard - I read the post incorrectly.

I've got plenty of free travel. When I first put this M/C on it worked fine but now after sitting for a while its sticking.

back to your original question about the mc
i think you need to use the correct non-power disc-drum mc otherwise you might get a real stiff pedal that takes a lot of leg pressure to work,
think how power brakes work with a non-running engine trying to stop.
if you cant find one from a mustang i would look for one from an early 70s truck.
sounds like you called only the one parts store, these days old parts are dropping off the warehouses and store shelves so you might need to do a bunch of phone work.

I checked with several of the Mustang specialty vendors online and nothing yet. I'll try Autozone next. All we have are AZ's and Oriellys here.

I don't know if the 68 mustang m/c is different to the 64-66 with disc/drum, but the m/c for those models with disk/drum was manual ONLY. Drum/drum did have power option however.

Try 67 mustang or 70s maverick

^ x 2 ...I used a manual disk/drum master cylinder from a 1974 Maverick on my 64 Comet disk conversion.

I'll give the Maverick M/C a try, hopefully they'll have one of those.

1976 maverick cardone part number 10-1614 for a remanufactured. I can't remember the prefix for the new ??-1614

Try Rock auto for looking up parts..

My wife works for on e of the major auto part places, we get 20-30% off parts and Rock auto is still cheaper with shipping. For the same brands.

Just did brakes on my 63 falcon wagon.. $80 cheaper at rock auto.

Nathan390 wrote:$80 cheaper at rock auto.

not to be getting off topic but is that USA made parts or imported.
i would rather spend the extra for USA parts.

Import versus import.. an apples to apples comparison..

It doesn't have to be from a mustang specifically. Try any ford passenger car 68 and up.

If this happened as a result of not being used, I would remove the residual valve to make certain it is not plugged. Seems easier and cheaper than a master cylinder!
Paul

Okay I pulled the old M/C and didn't really find much. Pulled the piston out and found just a wee bit of soft rust near the end, just past where the snap ring goes. Took some fine emery and removed it and replaced the piston assembly and bench bled it and put it back on and still have the sticking issue. I can see when I'm lying in the floorboard and operating the pedal that the piston is retracting fully and I've got enough free play. Any ideas as what to check now? I dont think this system has inline residual valves unless its built into the distribution block. Might pull the calipers and check the sliders but I dont think thats the issue as I've already done the diagostic check by cracking the bleeders when the calipers are stuck and they do release. Same as when I crack the line at the M/C.

'68 and up master cylinders have the residual valve(s) in the discharge port(s). It should be visible after removing the discharge port line fitting. That being said, I don't believe the Mustang cylinder utilized a resid valve on the disc port, only on the drum (forward port). If the sticking is alleviated by cracking the line at the m/c as you stated; the problem is either the residual valve or other blockage at or in the master cylinder.
As to substituting a power -assisted cylinder for the non-power; I believe you will find a substantial difference in the depth of the rod mounting area of the piston. Can it be adapted? Probably, but it would be much easier to replace in kind. Replacements ARE out there. As others noted it doesn't have to be a Mustang application. I would definitely stay with a '68 up application, however, due to the federally mandated changes.
Paul

One other thing to note and this may have been my oversight but the M/C that I put on it has the same size bowls front and rear. Wouldn't this indicate a non-power drum/drum M/C? I thought that the disc/drum M/C's had the larger bowl for the disc due to the increased fluid capacity of the calipers.