- Wheel Tractor-Scraper:
- 621H (S/N: DBK1-UP; EAZ1-UP)
- 623H (S/N: DBF1-UP)
- 627H (S/N: DBW1-UP)
The new special instruction contains the information and procedures that are required in order to upgrade the powered access ladder actuator on certain Wheel Tractor-Scrapers. The new actuator contains an internal limit switch. The internal limit switch will stop the actuation at a certain position when the powered access ladder is raised to the STOWED Position. The new actuator still uses an internal clutch to stop the actuation when the powered access ladder is lowered.
For a complete list of materials and the correct procedure that is needed in order to install the new actuator, refer to Special Instruction, REHS9821, "Procedure for Replacing the Actuator on Certain H Series Wheel Tractor-Scrapers Equipped with Powered Access Ladders"
The special instructions can be found on the Caterpillar Service Information System (SIS) and through the normal literature distribution system at your local Cat dealer.