1950 Dodge Master Cylinder Rebuild Question

[1950DodgeC]

I am in the process of rebuilding my master cylinder, but I am not sure where 1 gasket goes. I have a book but it doesnt seem to be very clear on where it may go. When I took the old one apart, this gasket was not inside it. The gasket or O-ring I am talking about is on the bottom part of the attached picture. The little black round one.

[Don Coatney]

This might help.

[62rebelP23]

it probably got pummelled to pieces over the years, and simply disintegrated.

[1950B2CToledoOH]

Does that rubber washer replace the metal one that goes between the piston and the main cup seal? New piston has a spring steel ring with holes punched in it about the size of the rubber washer. Bill

[De Soto Frank]

I am in the process of rebuilding my master cylinder, but I am not sure where 1 gasket goes. I have a book but it doesnt seem to be very clear on where it may go. When I took the old one apart, this gasket was not inside it. The gasket or O-ring I am talking about is on the bottom part of the attached picture. The little black round one.

 

Geeze... they didn't give you a piston return spring in the kit ?

That O-ring, or flat rubber washer that is about 5/8" to 7/8 -inch outside diameter, 3/8" to 1/2" inside-diameter, and about 1/8" thick, is the check-valve seat that goes in the "blind" end of the master cylinder.

 

If you look at the photo of the shop-manual page provided by Don Coatney in #2,  at the very left end of the top illustration (master cylinder), you will see a part labelled "Plug" ( with a second arrow pointing to the filler cap).  The "Plug" on the left, is the "end plug",  which threads-into the "blind" end of the master cylinder.  on the inside face of the end-plug, there should be a little "hub" or nipple in the center, that the rubber washer snaps-over.  This provides a sealing surface for the flat side of the salt-shaker type check-vlave at the top/center of your parts photo.  The piston return spring snaps-over the domed, perforated "shaker-top" of the check valve.  The "loose" cup  floats between the piston-end of the return spring and the aluminum piston itself.  The large, "skinny" washer/ring fits between the end-plug and the master cylinder body.

[wilbur46]

I did the job in the car.

I also did it from the back, by undoing the brake lines and removing the plug.

Its a lot easier to get at this end of the thing.

That o-ring seals the cap on the pedal side.

Loading it all from the plug end is duck soup.

Regards, W