Pioneer 4050-3 O-ring / backup ring question

[nfrost]

Does the Pioneer 4050-3 female coupler utilize a backup ring?

I've recently purchased a tractor with loader that utilize the Pioneer 4050-3 female and 4010-3 male fittings. All 4 loader connections were leaking when I bought it. The Parker literature indicates that this coupler takes a -116 (3/4 X 15/16 X 3/32) nitrile O-ring. I've installed new -116 O-rings in all 4 female couplers and they continue to leak just as bad. The -116 O-rings do not fill up the groove which leads me to think that they might require a backup ring, although the Parker spec sheet doesn't make mention of one. I even tried stepping up to a -210 (3/4 X 1 X 1/8) O-ring which fills up the groove nicely, the male will plug in, but the collar on the female won't slide down to lock it in. All coupling halves are old, but they don't look gouged up or abused.

Are my couplers just worn out? Seems that they shouldn't be since they're on a loader connections that don't get used often. What am I missing here?

thanks,

 

[oldnslo]

Backup ring should have size number as the O-ring.