1993 F-350 Dually 2 wheel drive
It has the axle that the drums can be pulled right off.

This got confusing. Got wheel cylinders from NAPA. When dissembling them for inspection and cleaning I saw that the bores were 1 1/16" and the old ones that I removed are 1 3/16" bores. I verified at NAPAonline that that the part numbers matched but they did not show the bore size. Cost Less had wheel cylinders with the same 1 3/16" bores. After I got home I was asking myself how do I know that the correct ones were installed.

The factory manual does not tell the bore size but gives a wheel cylinder part number of 2261.

Do you know what bore diameter is correct?

 

Called NAPA and talked to someone who knew what they were doing. The guy that got me the parts gave me one for a dual, the 1 3/16 and one for the single, the 1 1/16. The correct one was already installed. It could have been real bad if I did not catch the problem.

I will pay more for better quality if it is there, but the NAPA is the same drum as the one from Cost Less but $20 more. The NAPA drums might be poorer because they don't have a balancing weight. Neither one have the dust/water seal groove and weigh 3 pounds, 10% less. I am returning them to NAPA. The wheel cylinders are the same but $4 less.

 

Thanks for the reply back. I could not recall what the correct wheel cylinder bore size was off the top of my head. You found the answer before I could make it back to my PC.

 

Thanks for thinking about me.