willysmjeeps.com

Have been removing and cleaning brake parts and noticed this crack in my drum!
I have a bad feeling what everyone is going to say, but any hope for this drum or should I start looking for a replacement?

You need to replace it. Replace at least the hub if not the entire hub/drum/lug assembly.

In my restore I replaced both sides, same type of crack in same area. unexpected added expense, No fun.
Rusty

In the parts manual, it lists 2 different master cylinders. One is listed as a AL Body, the other is CI body. Can someone tell me the difference between the two.

It appears the different parts sources list varying master cylinders. Kaiser is a part number 805223, Debella is A-556, and Army Jeep Parts lists it as a CI body #805238 which matches up with the parts manual.

AL-ALUMINUM.
CI-CAST IRON.
I doubt you'll find any of the AL master cyls from the vendors.
Steer clear of Crown or Omix-Ada brands when shopping
brake parts if possible.

Thanks for that bit of information Rick! Makes sense...

Curious where folks have been getting their Master Cylinders from? I see Army Jeep Parts has a wagner.

I got mine from Kaiser. So far so good.
Rusty

Going to investigate my master cylinder to see if salvageable. Looks to be original AL body.

Corrosion was the big issue with the aluminum housings. The military dropped them very quickly. Ideally if you had a virgin housing you could have it anodized and that would slow down the corrosion issues. The problem with used cylinders is the military used the DOT 5 silicon brake fluid for a long time. It's in the pores of those old castings, both aluminum and steel, so that embedded silicon will always be an issue both with anodizing and with using with DOT 3/4 brake fluid.

I won't waste the space here arguing the pro's & con's of silicon Dot 5 vs old Dot 3/4 except to point out I don't use DOT 5 nor does the automobile industry today use it.

My advice with using a used aluminum housing you will have to stay with silicon fluid or expect problems down the road.