Face Seal O-Ring Fittings

[bvan]

I have a question about the sizing of face seal o-ring hydraulic fittings on a 1988 John Deere 80 series loader. I know they are fine thread but are the sized by outside OD, inside OD or something else? A 13/16" open end wrench is the smallest wrench that fits over the female end theads. The male lock nut is 15/16". A 3/4" SAE bolt fits inside male end with threads just touching. Thanks for your help.

 

[gatractorman]

The inside diameter of the fitting (where the oil actually flows thru) is how they determine size, however just to confuse things there are instances where fitting size and thread size matters, say if you wanted to step up or down a fitting or hose size then your fitting and thread size will be different, also the fitting nut sizes are not an industry standard some mfgrs. make the o.d. of the nut bigger than other mfgrs. which is not real important unless you have to walk 100yds. to swap out a hose then find the wrenches you had that fit the old hose dont fit the new hose. /forums/images/graemlins/mad.gif