Super 55 3 point

My dad just bought a super 55 last week the 3 point worked fine when he purchased it. Yesterday the thing won't lift at all. It's like something fell out as there is zero resistance. Could something fell off the rockshaft or the Piston came out as I can't see the pump dying instantly.
Thanks again

Well is there oil in the unit? Does it make any noise when you try to use the 3 point? Now in 1957 the 3 point was changed, so how about a tractor serial number to help us along. Does it have a remote valve to control a cylinder, if so will it operate the cylinder. Start there first.

Plenty of oil ,no noise, no remote

Here's what the manual says: 1. Start with the easy fix, check the oil level. 2. Unit raises in the Position Control but not in Draft Control.- Adjust the internal and external draft control linkage. On tractors prior to serial number 18 135 500 install improved external link spring, adjusting plunger and the new heat-treated hardened steel internal draft control shaft. 3. Take out the drain plug and start the engine. If little or no oil flows you are going to have to repair the pump or drive gears. 4. If the pump needs repair, you could have a dirty or faulty internal valve. There is a relief valve ball located inside the spool. The pilot spool may be stuck in the valve body. Check for a scored spool or valve spool bore in the body and replace both parts if either one is damaged. 5. Check for a bent or broken internal control ink. 6. Check oil leaks fro all "o" rings and pipe plugs in the housing, 7. Check cylinder and housing for cracks or broken sections. 8. Dirt under the ball in the external valve relief valve; Dirt under this valve will prevent the three-point hitch from lifting. Disassemble and clean valve. 9. Mechanical failure of the lifting linkages. Examine piston, cylinder, rocker arm and cross shaft. 10. Pump Not primed- Move control lever to extreme down position and operate engine at high idle speed for two or three minutes.

Does the PTO work? If not, the clutch cover could be stripped.

You did not answer my question on the serial number so I can determine if you have the early or late style unit. Also see the post above on the 550 with the loader. See if you have oil coming from that port.