Wheel Cylinders ?

[Kaiser2boy]

Ordered two wheel cylinders , a left and a right.
A little mix up came when I realized I was sent two lefts. Not a big problem the vendor said he will send out a right asap.
My question popped up when I took apart one of the originals just for fun.
They have two different pistons, a large one and a small one.
The originals have the large piston in the back and the small in the front. I am guessing this is right.

My delema started when I lifted the boot on the new one that had a small -L- stamped on it and it was just the oppisit. It has the small piston in the back and the large in the front.
Now I am wondering what one is right ?
Anyone know ..

[Doc Dave]

The large piston goes to the back to help the trailing shoe have more pressure and stopping power. The front shoe has a mechanical advantage with forward travel and does not need as much "oomph".
One other thing, are the pistons aluminum or steel? The originals were steel. Some of the replacements now are aluminum. Try and re-use your old steel pistons in the new iron castings.
You get corrosion from dissimilar metals when mixing aluminum and iron. I found out the hard way.

[Kaiser2boy]

Ha, I see that some one was in there prior to me. The pistons in the old cylinders were aluminum and looked like Swiss Cheese. The bores were pitted up badly also. One was sort of grown together and needed a few good thumps with a hamer to get the piston out.

Galvanic reaction I suspect.

The new ones are all cast iron and the pistons are steel. A magnet sticks to them so I know they are not aluminum.

Thanks for the tip on who goes in what direction and why.

[Clint Dixon]

Ha, I see that some one was in there prior to me. The pistons in the old cylinders were aluminum and looked like Swiss Cheese. The bores were pitted up badly also. One was sort of grown together and needed a few good thumps with a hamer to get the piston out.

Galvanic reaction I suspect.

The new ones are all cast iron and the pistons are steel. A magnet sticks to them so I know they are not aluminum.

Thanks for the tip on who goes in what direction and why.

Steel piston wheel cylinders are still available? What vendor were they purchased from?

[Kaiser2boy]

These came from Vintage Powerwagon inc.

[HWooldridge]

I just put my four wheels back together; two cylinder pistons are steel and two are aluminum. Not sure how well the aluminum will wear but I'm going to monitor them as time passes. I've also thought about building a few spares on the lathe - should be able to turn a decent surface finish then cut the slot with the mill.

[Kaiser2boy]

Interesting, were they all bought at the same time and place ?

The aluminum ones will work just as well as the steel and they wont rust. They do seem to sort of dissolve over the years. It may take 8 or 10 years for the galvanic action to eat them away. If the pistons have been anodized they last longer. If bare aluminum , not so long. The aluminum one are lighter, you may get better gas milage due to the lightness of them,,,, :-)

[HWooldridge]

Interesting, were they all bought at the same time and place ?

The aluminum ones will work just as well as the steel and they wont rust. They do seem to sort of dissolve over the years. It may take 8 or 10 years for the galvanic action to eat them away. If the pistons have been anodized they last longer. If bare aluminum , not so long. The aluminum one are lighter, you may get better gas milage due to the lightness of them,,,, :-)

No, I obtained them over time so two came from one source and the others from a second supplier. The aluminum ones are anodized.

[Doc Dave]

I don't think my aluminum pistons were anodized. I was sort of shocked at how they looked, vs the two cylinders with steel pistons.
I nearly had an accident due to one of the rear cylinders with aluminum pistons freezing up on me. I had to make a panic stop in the PW due to someone stopping short in front of me. With the Midland vacuum booster I locked 3 brakes up; the driver rear did not and this caused the rear of the truck to "crab" over into the other lane aways. Luckily no one was coming the other way right then.