tank for connection to an outside air supply. The valve permits the
system to be recharged with air from an outside source, releasing the
spring-actuated parking brakes. The vehicle may then be towed in an
emergency.
An outside air source can be used only if the protected system is in
operating condition. If air pressure cannot be restored in the protected
air system, the spring-actuated brakes must be released manually.
Releasing spring brake manually
Do not attempt to disassemble the parking brake chamber under
any circumstances. The high spring load may cause serious
injury if the chamber clamps are removed.
If air pressure is released from the spring brake chamber the power
spring applies the brake and, unless air pressure can be re-established,
the spring brake must be released as follows in order to move the
vehicle.
Block the wheels to prevent the vehicle from moving.
Unexpected and possibly sudden vehicle movement may occur if
these precautions are not taken.
Impact wrenches should not be used as they may damage the piston and
prevent proper caging of the spring. Do not apply more than 68 Nm (50
lb-ft) torque to the release bolt nut.
1. Remove the stud tool and nut
from the carrying pocket on the
brake chamber assembly.
2. Remove the access plug from the
end of the spring chamber.
3. Insert the release stud through
the opening in the chamber and into
the spring pressure plate.
Driving
123
The M20 & M22 wheel nuts are right-hand threads. Refer to the
following chart for approved wheel lug nut torque.
Wheel type Bolt size Wheel nut torque
10-hole disc 285.75
mm bolt circleM22 (22 by 1.5 mm) 610-677 Nm (450-500
lb-ft)
8-hole disc 19.5x6.75
mm bolt circleM20 (20 by 1.5 mm) 610-677 Nm (450-500
lb-ft)
The disc wheel nuts on your vehicle were tightened before delivery.
Recheck torque of nuts at 160 km (100 miles) and 800 km (500 miles) of
new vehicle operation or any time a wheel is removed. Reset to
recommended torque levels.
Tires are one of the weaker weight carrying components of the
vehicle. Do not overload the vehicle beyond safe load carrying
capacity.
Avoid hammering rim with steel hammers.
Never run the engine with one wheel off the ground.
Failure to retighten wheel lug nuts as required could allow the
wheel to come off while the vehicle is in motion, possibly causing
loss of vehicle control and collision. Loose wheel studs may also cause
shimmy and vibration.
Use of aftermarket wheel assemblies is not recommended; they
may be incompatible with your vehicle and may result in
equipment failure and possible injury. Replacement with used wheels is
not advised; they may have been treated harshly or have high mileage
and could fail without warning.
Maintenance and Specifications
216
