VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1938 Master Cylinder replacement

I ordered a new master cylinder for my '38 Master Deluxe Town Sedan. I removed the two bolts that secure it to the frame, and disconnected the fluid line in the rear. I removed the lock nut and spring on the front of the unit. My questions: There appears to be a thin pin that secures the pedal shaft to the master cylinder housing. I believe I am supposed to drive the pin out. I saw on an old forum post that it is driven out with a 5/32" pin punch. I ordered the pin punch and it is on it's way. If I drive it out, what do I replace it with? My second question: I do not suppose the pedal shaft will simply slide out of the master cylinder female ends. Does anyone have any suggestions on how to leverage that cylinder out? As everyone is aware, there is very little workspace around the cylinder. Thank you for taking the time to read this.

When I have done them on the 40’s cars you take the pedals off and leave the arms that the pedals attach to on the master cylinder and swap them over to the new master cylinder when you have it on the bench.

Thank you! That is helpful. I was trying to avoid removing the pedals, as they are waaayyy up there and hard to reach from under the car, but it looks like it will be unavoidable. I assume there is some sort of cotter pin or clevis holding the pedal assembly together at the joint. I will try to look harder. Thanks again!

Should be a 3/8 bolt that holds the pedal on.

Thanks again! I am looking forward to getting under the car again this weekend and getting the master cylinder in place. Next step will be to complete replacing the steel lines (I have about one-half of them installed), and then bleeding. That 3/8" bolt .... I would assume there is a cotter pin holding a lock nut in place, I will look.

I've attached some pictures.

One picture shows 2 pairs of pedals. The pedals have a male end on the bottom that is clamped inside the ARMS.

One pictures shows a bunch of master cylinders with arms. They seem to multiply in captivity. These are not the correct master cylinders for your car but the arms will look the same. The ends of the arms have an opening for the male end of the pedal and a single bolt that tightens up like a clamp to hold the pedal.

Final picture shows a pair of correct 1938 master Cylinders. The arms in the picture above mount to a cross shaft that mounts to the master cylinder.

Thanks for the photos! They are very helpful. I spent so much time underneath my car trying to reach up to unhook the pedal arms from the shaft, that I forgot I could simply open the hood and reach down and use my 6-point 1/2" box wrench and unscrew them. I did that, and I got the master cylinder out of the car, went to my vise, drove out the pin with a 3/16" pin punch (didn't take but one or two strong strokes to get it moving), and then worked on getting the pedal shaft out of the cylinder housing. Came up with an idea to use a spare bolt head on the female end, the opposite side of the clevis holder, and struck the bolt head, which hit the pedal shaft uniformly and drove it right out of the housing. Sharing that here, so others might use that technique if the shaft doesn't want to come out of the cylinder housing. Then I got my clutch and brake pedal arm back on the master cylinder without a problem. Placed the cylinder on the frame, and began hooking up the pedal arms, when I realized I had "turned" the pedal ends by prying them to loosen them, and the bolts won't go back in the pedal ends - the pedal female ends are now slightly skewed to each other. Not sure what to do; thinking about taking the assembly back out and placing a bolt (or something like that) in the slot and using my vise to "push" the ends back together again. But I am worried that pushing them together will make it too hard to get the pedal arm back in the hole! I am giving it some thought while I am at work today......

Be careful using force on the clamps on the pedal arms. The reason I have such a collection of arms is that MOST of mine are broken!

I've collected enough pieces to get myself a good pair so if yours are in decent shape, be careful with them. Maybe shim them or use heat during gentle persuasion...

Thanks for the tip! I have been VERY nervous about using a hammer anywhere on the car, even on the brake drums. I think I am going to thread a smaller diameter bolt through and snug it down with washers on each end. Thanks again for the tip!

Hey Canadiantim, new master cylinder is on and all brake pedals are attached! Tried to re-install brake spring and it shot across the engine bay; had to search and find it. And the chain for the transmission arm is not going over the lip - yet. That is all I have to wrap up the new master cylinder installation. If you know of a special way to pry the spring on, it would help. Otherwise I will use a vice grip on the spring and keep pushing until I get it hooked. I do have a drum brake spring tool, I wonder if it might work. Thanks

Not sure any tricks to get the return spring on.

You've seen my master cylinders and arms and they are on a shelf still lol as my car is at the most basic point of reassembly - fresh primer and not a single bolt yet...

Thanks! Going to work on it this afternoon, I have some ideas in my head. Good luck and Godspeed with your restoration!