O rings?

[Ol 54']

Looking for possibly an oversize O ring if there is such a thing? It goes on a selector valve shaft. I have tried a brand new O ring that is .500" i.d.
.6875 o.d.
.093 c.s.
It still leaks, now I checked the bore vs. the shaft on the selector valve clearance and it is about .004" .005" so would I need the valve bored with a new bushing or did I get a bad O ring made in who knows where. I talked to a guy and he thought they made O.S. O rings. He also said that the .093 c.s. should be like .125". By him measuring it up he told me I need a 208 O ring.. This here valve goes on my Dearborn model 19-8 front loader..

 

[MARK ROBKE]

This is not my field of expertise, BUT, I think your bore to shaft clearance should be closer to .001 or even less. The valve/shaft is what does most of the sealing, I think, not the o ring. Mark.

 

[Jim.ME]

CS (cross section) is the diameter of the O-ring wire so; 0.500" ID plus 0 .186" (that is 0.93" cross section times 2) = 0.686" (0.6875") which is the OD you posted.

Unless made for a special application, O-rings are made to standard sizes, there are no oversize for the standard sizes that I know of.

The spools of the valves of that era were fitted and lapped to the bores of the valve body, metal to metal clearance provided most of the sealing of the spools, as Mark posted. In my opinion the best fix is a new valve.

 

[Stan Coryell]

CS (cross section) is the diameter of the O-ring wire so; 0.500" ID plus 0 .186" (that is 0.93" cross section times 2) = 0.686" (0.6875") which is the OD you posted.

Unless made for a special application, O-rings are made to standard sizes, there are no oversize for the standard sizes that I know of.

The spools of the valves of that era were fitted and lapped to the bores of the valve body, metal to metal clearance provided most of the sealing of the spools, as Mark posted. In my opinion the best fix is a new valve.

I agreed with Mark and Jim. That spool looks pitted from corrosion. That would make it tough to measure with a standard micrometer. The wear is likely more than 0.004".

The valve is toast.

 

[Ol 54']

You know pretty much thought that my clearance was a little big? With that being said, where could I purchase a selector valve for my Dearborn model 19-8 loader?

 

[Ol 54']

Yeah kinda goofed up there on the valve I was talking about? It's called a loader control valve not a selector valve..

 

[Jim.ME]

You know pretty much thought that my clearance was a little big? With that being said, where could I purchase a selector valve for my Dearborn model 19-8 loader?

There are a number of places that sell loader valves, but you should have more info to work with in your search

Trip dump or hydraulic cylinders on the bucket? This makes a difference as to whether you need a one-spool valve or a two-spool valve.

Single or double acting lift cylinders? If single acting it will be best if you can find a valve designed for single acting cylinders.

Current connection type and sizes of the hoses hooked to your valve. This can avoid having to change hoses or buying adapters to go between your hoses and new valve. You may need adapters in any case or have to change some hoses due to the new valve port arrangement. Just something to be aware of.

A true loader valve will have a float position for the lift cylinder spool.

You will be looking for an open center valve, likely 10 to 15 gallon per minute range for a flow rating.

 

[m16ty]

If you have to do any machine work to that bore or shaft, you'll likely ruin both pieces. The bore and shaft are a lapped fit.

At the end of the day a replacement valve from a manufacturer like Prince is reasonably priced, likely cheaper than hiring machine work on your old valve.