Here's how one guy says to remove the rod, about half way down the page: http://www.mustangsteve.com/granadadiscs.html BTW, i just replace my '70 drum/drum MC with '76 disc/drum MC, the rod that came with the new MC was longer (too long?).
I just tried to remove the pushrod on my '75's old M/C. It don't come out. I actually stretched the pushrod trying to pry the master off of the pushrod that was held in the vise. I'm sure if I tried harder I'd either pull the pushrod apart or break the clip out of the M/C. BTW I had to cut and re-weld the pushrod to get the pedal height down to where it needed to be. But then again, that's on a Dodge M/C. The total length of the pushrod end to end was 3 3/4" which bought the pedal height down to where I like it. I had asked about a adjustable one at the parts store, but the shortest that it would go was 4 1/4"...which was of course too long for what I needed.
This thread happened at just the right time. I installed my new disc/drum MC this morning as part of my conversion. Sure enough, the rod was too long. Frome the rear of the MC mounting flange to the hole center of the rod was 5 1/2", the old drum/drum rod measured 5" flange to hole center. I cut 1/2" out of the new rod and welded it back together. Then I realized the new MC is the type that doesn't secure the rod, no internal groove to capture the snap ring. The brake pedal can move far enough rearward to pull the rod right out of the MC (thanks for the heads up M.A.V.). Is that a dumb design or what? I'm using a big hose clamp around the steering column to hold an L bracket to act as an adjustable pedal stop. It's up under the dash so you don't see it.
I'm glad you guys mentioned the fact that the rod can come out of the M/C. I know a guy that raced a Pinto for years and his came out on a pass, ran through a fence, out into a pasture, and got pretty close to a chicken house before he spun it around and drove it back. kinda scary if you think about it, I'm gonna triple-check mine before I even try to make a shake-down pass.
Okay guys, here's the deal. I did the front disc conversion on my '73 almost 14 years ago (October of '90). You basically have two options (besides cutting the pushrod). 1. Right now I am using a '75 non-power disc master cylinder with a pushrod from a '73 drum master cylinder. Had to buy 2 master cylinders to achieve this, one of each, (they're cheap enough though) and they both came with the pushrods in the box and not installed. The drum m/c pushrod is shorter. They both have the groove and the snap-ring so it cannot come out once it's put in. Pedal height is same as it was originally with the drum brakes. 2. The other option (which I originally used) is to use the '74-'77 non-power master cylinder along with its supplied pushrod, AND get a brake pedal from a '75-77 Maverick or Comet (should be dirt-cheap from a junk yard). The geometry is different so the pedal will not be as high as your '70-'73 pedal, HOWEVER the '75-'77 pedal uses a bolt and nut to mount it instead of a steel pin & clip, so the hole is ever so slightly smaller which does not allow the little plastic bushings to fit (the pin fits but not the bushings). If you leave the plastic bushings out, there will be lots of side-to-side pedal "slop" and it will hang crooked. So if you decide to go this route, you need to take the later model pedal to a machine shop and have it bored/honed to be the same size as your original pedal. Only a very slight amount of metal will have to be removed because the opening is barely smaller than that of your original pedal. I like these two methods better than cutting and re-welding stuff. *NOTE*: The ONLY Maverick master cylinders I am aware of that do not have the groove for the snap-ring are the power units. All of the manual units I have ever seen have the groove so that the rod cannot come out while you're driving. I'm not sure about how the '74 pedal geometry compares to '73 and older or '75 and newer, but I know it uses the same mounting system (steel pin and clip) as the '70-'73. Of course I am still curious to know if there is a special tool for removing a pushrod, as this obviously must be done to rebuild core master cylinders. I hope this information is helpful to anyone who wants to convert their Maverick/Comet to disc brakes (which I HIGHLY recomend)...
