so looks like there are two options available to rebuild you 3 point cylinder, the first is to get the Hydraulic piston assembly( this has all the seals + the piston in the assembly)( TNA4010000C9 )( should be priced around $189 from who ever you purchase from ), the second would be to get each seal individually 1. U-Packing(TNA4020000A9 $45.45) 2. Back-Up Ring (TB3640000A4 $12.40) 3. Wear Ring (TNA401C000A4 $29.15) the costs on the are a rough estimate based on what Branson Suggests to charge these prices may vary depending on from who and where you purchase them. These Prices do not include typical freight costs to ship to you.
Hopefully this helps you out.