Front wheel cylinders

[95ttoplt1]

Well I got my front brake parts from roberts today and recieved the same kits I got from NAPA a week ago. They are for a stepped wheel cylinder 1 3/8 and 1 1/4 cups.

The wheel cylinders I pulled out of my truck are 1 3/8 all the way through, no step, with two 1 3/8 cups and red annodized pistons.

Which is correct?

[MBF]

Just replaced the rears on my 52 1 ton. They were stepped. Got them from NAPA. They're different left to right, but the front and the rears use the same cylinders. Mike

[95ttoplt1]

Just replaced the rears on my 52 1 ton. They were stepped. Got them from NAPA. They're different left to right, but the front and the rears use the same cylinders. Mike

I have dual single pistons in the rear, way different than the fronts. I think mine must have been replaced at some time??

[B1B Keven]

I have dual single pistons in the rear, way different than the fronts. I think mine must have been replaced at some time??

My '49 has dual single pistons in the rear.

[pflaming]

My '52 has one cylinder in the front which is stepped. It has two "single" cylinders in the rear. I am under the impression that there are two types of brake setups but I'm no expert.

[wallytoo]

I have dual single pistons in the rear, way different than the fronts. I think mine must have been replaced at some time??

your rear cylinders are supposed to be paired. your fronts should be stepped.

on the 1.5-ton and a little larger, front and rear are single, stepped cylinders (the BIG trucks are different, too.)

[Merle Coggins]

Yes, 1/2 and 3/4 ton trucks used twin single cylinders on the rears and double sided stepped cylniders up front. The 1 ton used the double ended cylinders at both ends.

If your front cylinders have the same size pistons at both ends than someone replaced them at one time with a "close match" that isn't as close as it should have been.

Merle

[ggdad1951]

my '51 had the two different bore sizes as well on all 4 wheels with each side matching.

[John-T-53]

From what I understand about drum brakes:

The different cylinder diameters coincide with the primary and secondary shoes, with the bigger bore being on the primary side. These are non-servo brakes, since the shoe ends are anchored.

I've seen stepped wheel cylinders used with shoes of equal length lining, compared to non-stepped cylinders used with shoes of differing lining lengths, thus two ways to achieve primary and secondary shoes - the first by piston pressure, the second by fricton surface area.

I'm deducing about 50% of this from observation only, please correct me or contribute more info if you can.

Thanks,

[pflaming]

I didn't realize the front shoes could be different, assuming mine are originals. I figured the dual size bores was so that one shoe activated one easy stops and the second on a hard stop and in so doing saved on wear.

The more I work on this old truck, which is taking longer than I thought, the more a appreciate the inginuitey of those engineeres. The brake light switch atop the MC is a real marvel.

[95ttoplt1]

So i went back to NAPA today to get wheel cylinders and it turns out that mine are correct!

There is an "early" 1 3/8 non stepped, and a "Late" style that is stepped.

The part number for the stepped rebuild kit is 6.

They dont make a kit for the non-stepped, kinda odd. But I can combine the #6 kit from NAPA and the kit from Roberts to make it all work.

The kit from NAPA is a little more complete than the kit you get from Roberts. It comes with a new spring, but they do cost a little more. It was $27 with tax and everything for the kits from NAPA.