OM3013 02/99 Operation - Section 3 Operating Instructions Page 3-13 3. If the engine is NOT operable, never haul the truck over 800m (2,625 ft.). 1. Block disabled truck to prevent movement and confirm safety in the surrounding area. 2. At the parking brake relay valve, remove both air hoses (4) connected to the air chambers of the parking brake spring cylinder assemblies (5). If the towing distance surpasses that limit, be sure to remove the drive shaft between the transmission and the differential case (if final drive sun gears have not been removed). The towing speed must not be greater than 8 km/h (5 mph). 4.
Inspect tow bar for capacity (it should be strong enough to tow 1.5 times the gross vehicle weight of truck being towed). 5. Determine that towing vehicle has adequate capacity to both move and stop the towed truck under all conditions. 6. Protect both operators in the event of tow bar failure. 7. Release disabled truck brakes and remove all blocking. Do not tow the truck any faster than 8 kph (5 MPH). 8. Sudden movement may cause tow bar failure. Smooth and gradual truck movement is pre- ferred. 3. Connect these hoses together using a "tee" fit- ting with compatible thread ends. 9. Minimize tow angle at all times - NEVER EXCEED 30°.
The towed truck must be steered in the direction of the tow bar. 4. Connect third connector of "tee" to a hose from an air supply of sufficient capacity to release calipers. Apply air and release brake. 5. With parking brake released, turn adjustment bolt (2) counterclockwise, and check for "play" in linkage (3). Remove pin (1). Repeat for other caliper. Disconnect air supply. BRAKE RELEASE 6. With parking brake disconnected, remove blocking and immediately move the truck to a safe place. Refer to INSTRUCTIONS FOR TOWING THE MACHINE.
Releasing Parking Brake And Emergency Brake After Being Actuated In An Emergency If the pressure inside the air tank drops abnormally due to some problem, such as leakage of air from the air circuit, the parking brake and emergency brake are automatically actuated. RELEASE OF PARKING BRAKE If the air system is not operating, the service brakes will not apply; this is very dangerous. Be sure to tow the truck at low speed, keeping the engine running (if possible) and always be ready to steer. The parking brake is a dry disc brake mounted on the rear drive shaft at the differential input with two (2) spring-applied, air-released calipers.
Each caliper is individually applied/released through separate air chamber actuators (spring cylinder assemblies). If the parking brake can not be released after its emer- gency application - even if the parking brake valve lever is put in RELEASE position - take the following actions to release the parking brake: Refer to Section 4, Lubrication & Service; Parking Brake Inspection and Adjustment , for instructions for reconnecting and adjusting park brake.