Understanding a 1947 Brake Cylinder . . I Think!

[Bingster]

So I was cleaning up my 1947 front Lockeed brake cylinders with the intent to rebuild them. As I was peeking into the "hose holes" opposite the bleeder valves, I discovered something that really had me puzzled for awhile. I almost tossed them. Maybe I still will, but I'm wanting another opinion about this.

 

On two of the cylinders, that hole next to the bleeder valve was threaded and had a hole in the bottom to let the oil pass to the back of the piston and on to the bottom cylinder. Fine.

 

The other two cylinders had these same holes next to the bleeder valve, but the bottoms of these holes were solid casting. No threads, no oil holes. I thought that rust must have plugged these holes solid, but probing with a small screwdriver proved that there never were holes drilled. It really was a solid bottom. 

 

I had just assumed that all four cylinders - with the exception of their being an upper left and upper right - were identical in design. So I must have two bum cylinders. Off I go to Rock Auto or Bernbaum.  But after staring at a parts book and service manual trying to figure out their oil path, it suddenly hit me:  maybe that blocked up hole on each of the two cylinders was designed to be blocked, and served as the "dead end" of the oil path between the upper and lower cylinders. There wasn't any need to pass oil through the bottom cylinder to any other parts like the uppers did.

 

Would that be an accurate assessment?

 

 

[Curt Lee]

First; against every temptation, never throw away small stuff like these. bag 'em tag 'em and keep them against that first day of the forty days of rain.

Second; you're probably 100% correct in your theory. A step skipped saved manufacturing time and gave the inventory guys two more numbers to track!

[Bingster]

Thanks.  I was looking at some contemporary cylinders online and they seem sturdy enough - it's a pretty simple concept - but I've heard mixed results about their being made in China.  Somebody (sorry) gave me a good idea to buy new and re-sleeve the old later, but the old castings look as though they could survive an atomic blast. They'd melt of course, but they are quite beefy compared to the new.

 

I haven't found any new pistons, however, online. The rubber part and the springs yes, but no pistons. I did get another tip on here to find the inside diameter spec of the cylinder and see how much you can hone.  The ID is 1 1/8, and the parts book showed a "standard" width piston and another at .010. This would allow however many hones between "Standard" and .010. So it doesn't look as thought my cylinders have been honed, at least not much.