Instructions for the  Lexmark T522, T520 Fuser Replacement Procedure
These machines have a 250,000 PM cycle which is the rating for the fusing assembly. Most your OEM fusers will last the whole life. Rebuilt fusers cost have as much and I’d say they have about half the life cycle of the OEM fusers. With that being said I do, on occasion, run into one that will surprise me and make it the whole life cycle. Most these machine don’t get the heaviest of usage so if they make it to 125 to 175 thousand and the fuser last 3 to 5 years then your in good shape. Below you will find the  Lexmark T522, T520 Fuser Replacement Procedure along with links to purchase a replacement fuser if it is still needed.
Lexmark Optra T 522 520 Fuser Kit 99A2423 Refurbished
Fuser Wiper Assembly Door Removal
1. Squeeze the two latches together, and pull up.
2. Remove the fuser wiper cover assembly.
Redrive  Cap Cover Removal
1. Pull up on the right side of the redrive cap cover to remove.
2. Remove the redrive cap cover.
Redrive Door Removal
1. With the redrive door partially open, lift and free the left side.
2. Remove the redrive door.
Redrive Assembly Removal
1. Remove the redrive door assembly.
2. Remove the redrive exit cover.
3. Remove the redrive assembly mounting screws.
4. Release the redrive assembly mounting latches and remove the redrive assembly.
Right Cover Removal
1. Open the upper and bottom front covers.
2. Release the cover latch and remove the right cover mounting screw.
3. Remove the redrive assembly.
4. Remove the right side cover mounting screw.
5. Remove the right side cover.
Low Voltage Power Supply Removal
1. Remove the right cover.
2. Remove the LVPS mounting screws from the rear of the  bottom pan.
3. Pull the LVPS assembly from the right side of the printer
4. Press the release latch on the fuser lamp cable connector  and disconnect from the LVPS.
Lexmark T522, T520 Fuser Replacement Procedure
1. Remove the redrive assembly.
2. Remove the ground screw.
3. Remove the fuser mounting screws.
4. Disconnect the AC fuser lamp connector from the LVPS.
5. Disconnect the DC fuser cable from the engine board.
6. Remove the fuser.