Ford 1220 Three Point not holding

[Justadudewithatractor]

Hi and again, thanks in advance,

The three point lifts and operates almost as should, but as soon as I turn the tractor off, the three point lowers to the ground with the lever in the up position. There's a trim mower on the back at the moment and it never did this. I'm thinking there might be a crack in the ring on the piston. I haven't checked because it's a TIGHT area under the seat.

This started about a month ago when the adapter for the return line cracked. We fixed that, but now this is happening.

Any suggestions?

Thanks!

NOTE: I just ran the tractor for about 1.5 hours. I was hearing some loud noises coming from under the seat and the three point lift was barely operational. In my limited experience, that points to the ring around the piston. I think! Thanks again!

NOTE: Just started the tractor fairly cool and the 3point lifted no problem. I believe the type of hydraulic fluid is the issue. The owner of the tractor put 132 in and I believe it needs 134D. I'll start there.