Just bought a case 1840 2400 hours. Right side will move but very week. Gets worse as everything warms up. Spool was leaking on the tandom pump replaced the oring and stopped the leak but no difference. Swapped hoses to drive and problem switched to left side so definitely a problem on the right side of tandem pump. Popped end covers off servo piston and checked for metal or wear all looked pretty clean. Should servo pistons slide easy and should I be able to pull servo pistons out while still in the machine or does the whole tandem pump need removed and tore down to lap and polish. My belief is the servo pistons arnt stroking but not 100% sure
Another worry is I installed new orings and old ones were completely gone and no sign of them when I pulled spool