Let me see if I can put into words what I am trying to do. First off its my 39 Ford Sedan and I am removing the old M/C and replacing with a new Mustang M/C for front disk brakes. I have a front brake kit from Speedway and will install after I get the m/c figured out and plumed. I figured the m/c would be the hardest part of the deal since I am working in a small area with car jacked up and laying on the floor under it. Not bad if your a young man but I am far from that now. Anyway, the old is off and I am mocking up the new. I am using the Chassis Engineering adapter which is 3/4 inch thick which fits good. The new Mustang m/c did not come with a push rod so I figure I will use the stock one from car. I had a good peddle with old setup so if I extend the old push rod the 3/4 inch to compensate for the adapter will I be in the ballpark so to speak? I know that I do have to have a small amount of play to keep the rod from pushing aginst the piston. Its easer to make adjustment off the car than under and in that small space. Glad to hear from anyone that has done this and I am open to suggestions. Thanks, Doug.
I wouldn't assume you could extend the rod 3/4" and be ok. The piston in the new master may not be the same. You're going to have to measure and compare the masters and figure out how long the push rod has to be.
If it's an original Ford master cylinder pushrod it should be adjustable. As cretin said, measure the master cylinders to make sure the piston is the same, otherwise you'll have to adjust for that also.
I think you will need more than 3/4 inch, more like 1 1/2 inches. I've done this a few times, and just did it last week. The new MC should have come with a pushrod. I cut the old one off at the base, drill into it about a quarter of an inch. Then I cut the new one about a quarter of an inch below the last ridge. I then inserted the new rod into the newly drilled hole, and weld around perimeter. I'll snap a shot later today. Rich
Power masters would not come with a push rod, unless they are a universal replacement. (Their push rod is part of the booster) Ford (Bendix) power masters normally have deep push rod bores, needed on manual systems that don't use stock type push rod retainers. With the pedal fully returned by it's own return spring, adjust the push rod for about 1/16" clearance. Most important is to make sure the pedal can fully stroke the master before the pedal runs out of travel.
I did this conversion on my '40 over 25 years ago.....non-power. Used a Mustang 15/16 inch bore MC. The original rod did not extend far enough. Machined a new rod 1 inch longer. It has been working well ever since. The cover on the Ford MC is too high to clear the floorboard....had to section it, and modify the bail to fit correctly. If I did it again, would recommend the Corvette MC....which is on my '35.
Thanks for the ideas. The new non power m/c did not come with a push rod and the stock one had very little adjustment in it to be safe but did come apart in two peices. I measured the two m/c pistons and the were the same. I know the thickness of the C/E adapter was 3/4 inch so I started with a 1 3/4 inch coupling nut and cut it down to 1 inch put the pushrod and m/c back together and it was to long so I just played with the coupling nut taking off a little at a time till I got the length I needed with 1/16 of end play. Thanks again.
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