that under the load roller on the opposite side
of the rail.
Perform the following procedure to adjust the
mast load rollers.
1.
Use a pry bar to move the rails from side to
side while measuring the movement.
Measure the movement in a minimum of
three different positions of the rails.
2.
Separate the rails and add or remove shims
as required. Slide the rail all the way from top
to bottom and find the tightest fit.
3.
Repeat Steps 1 and 2 until there is 0.001 to
0.010 in. clearance at the point of tightest fit.
DO NOT shim the load rollers too tight.
Check for free movement by sliding rail
through full extension by hand.
4.
Measure the distance between the channels of
the rails on the top and bottom. Change
shims to keep the distance equal at the top
and bottom so that the rails are parallel within
0.060 in.
Brass Set Screws
NOTE
The brass set screws can only be adjusted
with the mast installed on the truck and the
mast tilted forward.
The brass set screws reduce the front to back
movement between the rails. The brass set
screws are too loose if there is excessive front to
back play in the rails when extended. On the
triplex mast, there are two pairs of brass set
screws. One pair is located at the top of the outer
rail, secured by smaller set screws. The other pair
is located at the top of the middle rail, secured by
jam nuts.
1.
Tilt the mast fully forward. Loosen the small
set screw or jam nut.
2.
Turn the brass set screw through the rail so it
is tight against the next rail. Back the screw
off by ¼ turn.
3.
Tighten the small set screw or jam nut to lock
the brass set screw.
4.
Operate the mast and check the adjustment.
Outer Cylinder Shims
Shims between the outer cylinder rods and the
middle rail keep the mast from being cocked to
one side at full extension. If one cylinder extends
E
lectric
C
ounterbalance
H
igh
O
utput
Elevating
3/10/00
7.11
UPPER
LOWER
1
2
B
C
1
1
A
B
C
1. Shim load rollers to 0.000 -
A
0.010 in. at tightest point.
2. Brass set screws.
±0.060
±0.060
±0.060
1
2
LOAD
ROLLERS
LOAD
ROLLERS
FIGURE 7.8 - MAST ADJUSTMENTS
