Correct master cylinder for 1939

[Rustynutz52]

I am curious if anyone can give me some guidance as to the correct master cylinder for a 39. I was hoping mine was original but it appears to have been changed out at some point to one with plastic cap and no part number. The plan was to have it sleeved by white post, but dont want to waste money on it if its not correct.
Thanks Mike

[Kube]

I think this may help. Note the cap is metal. That little square in the center is vented of course and is only perhaps 3/16" in height.
Mike

[Charlie Stephens]

Don't go by the cap, it could have been easily replaced. Post some pictures. If you included your general location in your post or in your profile someone might suggest where to go to see an original. There is a good line drawing of a master cylinder on page 36 of the Green Bible. I hate to use this book as a reference but in this case it is probably correct.

Charlie Stephens

[Rowdy]

Most master cylinders have a part number on them. I do not have the correct Bendix number infront of me, but that would be a good place to start. With the parts I bought a couple of weeks ago included was a master cylinder and 39 brake pedal assembly. It is from a one ton, so it may have a different part number. I am hoping to use them and can look at the part number Tuesday. The one ton used the same front brakes (other than the drums and hubs) as the passenger car. Rod

[Gary in La.]

The P/n on the master cylinder casting should be 1050. It was used by most brands (Bendix,Wagner,Eisis).

[Rustynutz52]

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Kube, I am curious if the top of the body has rounded edges or more square edges. The photo looks like it is more square edged. Another member sent me a photo of a used core he has and it has rounded edges on the top portion.
i am going to look at diagram in green book.

Thanks Mike

[V12Bill]

I have bought master cylinders at NAPA. Be careful as some of them are from China.

[Walt Dupont--Me.]

Originally Posted by Kube

I think this may help. Note the cap is metal. That little square in the center is vented of course and is only perhaps 3/16" in height.
Mike

Kube, when you run through a rain storm do you have to take the body off and polish that frame, It's a beauty. Walt

[Terry,OH]

Here is a couple more photos, yes the body is rounded. The body on this is marked 1050 but does not have the typical Mfg name embossed. The caps are smaller that the larger plastic and are white metal, I have seen some from later cylinders that have steel caps.

[Vic Piano]

Every "new" or rebuilt master cylinder I've ever gotten has come with the plastic cap... I think its just an opportunity to "up sell" the correct cap at an additional cost.

[Kube]

Terry, OH. has offered up an important point, one that I misspoke of. The cap is, as he correctly states, white metal.
The factory installed master cylinders had seem to come in both the "rounded" design as well as the "squared" design. The drawings do not specify only one design as permissible. As this part was outsourced, often times, the aesthetics's were not a "cut in stone" feature. Rather, the functionality took precedence.
Also, one must keep in mind that this very cylinder was used on a lot of different vehicles (GM mostly) through the early 1950's.
I am not as yet convinced that any manufacturers name, etc. was cast in to the authentic 1939 - '40 cylinder. However, here too, the discretion was often left to the manufacturer.
I can state with confidence that "Made in the USA" as seen on many of these is incorrect.

[Kube]

Originally Posted by Walt Dupont--Me.

Kube, when you run through a rain storm do you have to take the body off and polish that frame, It's a beauty. Walt

Thanks for the kind words Walt. This chassis was for a '40 coupe I'd done fairly recently.
All jokes aside though, when in the rare instance a frame gets dirty, they clean up very easily. Most of what you see is powder finished. Another car I did, a '40 coupe, in 1994, still looks this nice underneath. For restoration purposes, heck especially for "drivers", I highly recommend powder finishing.