How to replace the oil pipe and cylinder of a two-post car lift?

Replacing the oil pipe and cylinder of a two-post car lift needs to be done carefully because it involves the hydraulic system and safety-critical components. I'll outline the process step by step so you can follow safely:
Safety Precautions
1.Disconnect power supply to the car lift.
2.Lower the post car lift completely and ensure no vehicle is on it.
3.Support the arms and carriage with blocks or a jack to prevent accidental movement.
4. Wear gloves and eye protection-hydraulic oil is under pressure.
Replacement Steps
1. Drain Hydraulic Pressure
Press the "down" button of the 2 post car lift to release system pressure.
Open the oil tank cap slightly to equalize pressure.
2. Remove the Oil Pipe
Locate the hydraulic hose connecting the pump unit to the cylinder(s).
Place a pan under the connection to catch leaking oil.
Use wrenches to disconnect the fittings carefully.
Cap or cover open fittings to prevent contamination.
3. Remove the Cylinder
Depending on your car lift design, the cylinder is usually fixed inside one of the posts.
Disconnect the top pulley and chain/cable (mark positions before removal).
Unbolt the cylinder from the base bracket.
Carefully slide or lift out the old cylinder (may need assistance, it's heavy).
4. Install the New Cylinder
Place the new cylinder into the post and secure it with bolts.
Reconnect the chain/cable and pulleys (adjust to original positions).
Make sure alignment is correct and movement is smooth.
5. Install the New Oil Pipe
Route the new hydraulic hose the same way as the old one.
Connect fittings tightly using PTFE tape/sealant if required (don't overtighten).
Ensure no twisting or sharp bends in the hose.
6. Refill Hydraulic Oil
Fill the oil reservoir with fresh hydraulic oil (ISO 32/46 depending on manufacturer).
Do not overfill.
7. Bleed the Hydraulic System
Raise the lift slowly (without load) to the top, then lower it fully.
Repeat several times to expel air from the cylinder and hose.
Check oil level again and top up if needed.
8. Inspection
Inspect all fittings for leaks.
Check lift synchronization (both arms rising evenly).
Run the lift with no load before testing with a vehicle.