3 point hitch O ring.

[Neat 1500]

My 3 point ( on the 1500 ) wont hold its ground any more, even closing the valve it still drops so i am assuming my O ring is leaking past. i want to pull it down but have it together quickly. i have a fairly comprehensive O ring kit so i should be OK, question is does someone remember what size it is? i take it shes the round type and not a square one? i have looked at the Hoye diagrams but no specs ( an O rings an O ring!) might even have 2 on it. looks to be just a matter of unbolting the top section and lifting it off?

 

[HoyeTractor]

The oring on the lift cylinder is a P55. They are a JIS (Japanese Industrial Standard) size oring which is not very common here. It is actually a 54.4mm ID.