Great Dane 42101401 - Manual (Page 15)

SUSPENSIONS
Check wear pads in hangers. If they are wearing thin,
install new pads or the spring will cause permanent
damage to the hanger. Do not operate with broken
spring leaves.
Check to see if all springs can make proper contact
with wear pads. Twisted springs and cocked hangers
can cause uneven spring contact with wear pads, and
will result in excessive wear on the suspension.
Check to see if there is sufficient clearance between
the springs and the sides of the hangers and rockers.
Improper spring centers or hanger spacing can create
binding in this area, resulting in excessive wear.
Check the equalizer to see that there are no obstruc-
tions to movement during operations. If equalizer
movement is restricted by an obstruction, the axle
“walk” will not be sufficient and damage will result.
Check the rocker beam to see if there is adequate
clearance between the ends of the spring and the
rocker beam hub when the axle is both loaded and
unloaded.
Check welds to see that no cracking has occurred
between the spring seats and axles, and between the
hangers and sub-frame.
Threaded fasteners should be checked for proper
tightness after an initial break-in period of 3,000 to
5,000 miles. Torque should be rechecked every
25,000 miles.
The replacement of worn bushings is considered
normal preventative maintenance. Bushings showing
signs of wear should be replaced before they damage
the parts they are pressed into. Routine torque
maintenance will prolong the life of bushings.
AIR-SPRING SUSPENSION
The air-spring suspension height is controlled by height
control valves that maintain a constant trailer height
by pressurizing or exhausting air in the air springs as
needed to support the load being carried.
You must build up to and maintain your trailer’s air
pressure at more than 70 psi for van trailers and 80 psi
for platform tailers before operating the trailer. The air
protection valve will not operate until you have 70 psi
on van trailer and 80 psi on platform trailers in the
system. This valve automatically maintains a safe air
brake pressure higher than 70 psi for van trailers and
80 psi for platform trailers in the event of an air loss
due to a failure in the suspension system.
If an air-spring failure occurs on one side, it is
recommended to completely deflate the suspension
and temporarily operate on the air springs’ internal
rubber bumpers to allow your trailer to be moved to
a shop for repairs.
To deflate or cut off the air pressure to the damaged
air spring, disconnect the height control valve actuating
levers from their link assemblies and rotate to the
vertical down position.
Check air lines and fittings for leaks.
Check air springs and proper clearance when inflated
– minimum clearance is 1 3/4".
Check axle clamp group to be sure that all bolted
connections are properly torqued. For proper torque
requirement refer to the suspension manufacturer’s
maintenance manual. Worn component parts or loose
U-bolts can allow the vehicle to roll or sway.
Excessive play in the front pivot connection area can
cause premature tire wear and erratic handling
characteristics. Loose bolts at this connection will
cause the rubber bushings to wear out prematurely.
Fill to
oil level line
on hub cap
window
Lubrication fill oil (static)
Lubrication fill semi-fluid grease (No. 00)
WARNING Broken spring leaves, missing or
loose U-bolts, or other defective conditions likely
to cause axle shift are hazardous.
13
Brush a light film of
grease on axle nut and spindle end and
around inner surface of hubcap being
careful not to cover vent plug
Fill to 3 and
9 o’clock level