brake wheel cylinders on 41 plymouth

[MRR41 COUPE]

Thanks for all the information. I was wondering about that boot expander that was in the parts book. . It does make since to have it to at least protect the rubber boots from the edges of the internal spring. I have not seen this part anywhere except in the parts books. Thanks again for the information

[captbrian41]

Hi Mike, it's been a few years since I took the rears apart, with great difficulty getting the drums off I might add, but I remember the cylinder was two rubber cups and two pistons, 11/8 on the back and 11/4 on the front side of the cylinder, plus the dirt cup for the rods.  Cups first, pistons next, rods  and finally the dirt cups over the outside edge of the cyliner. Even though mine were 65 plus years old  and rusty on the bottom of each cylinder they honed up nicely the pistons still fit good and NAPA carries the rubber cups. So good luck, but it sounds like something might be missing in your cylinders. Go to a website called Detroit Iron and you can get a  CD that has all the serviced info for the early Plymouths with great exploded views of everthing. By the way I flushed the lines well with clear brake fluid and used Dot 3 after buttoning up everything. Also made a remote bleeder out of small home garden sprayer so that i could keep the Master filled while laying at the cylinder I was bleeding. Great little invention. No extra person and no pump and hold and refilling the master by hand. Always discard any fluid that passes through the cylinder even if it's clean just for safety sake.

[MRR41 COUPE]

I'm working on my rr wheel cylinder and noticed that the parts book calls for a cup expander. My 41 never had metal expanders on it. I have about 8 untouched wheel cylinders and the two I took apart do not have metal cup expanders, Were they eliminated or am I just missing them? These brakes did not work great for me in 1966 and their still a pain in the butt.
Mike