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Air Motor and Throat Service
309966H 11
Air Motor and Throat Service
• Before you start, be sure you have all necessary
parts on hand. Repair Kit 246919 is available for the
motor. Use all the parts in the kit for the best results.
Parts included in the kit are marked with an asterisk
(*) in the parts drawing and list.
• Two accessory tools should be used. Order Padded
Pliers, 248198, to grip the trip rod without damaging
its surface. Use Gauge, 15E796 (included in kit), to
ensure the proper clearance between the poppets
and seat of the transfer valve.
Disassembly
1. Flush the pump.
2. Relieve the pressure before you proceed.
3. Disconnect the hoses, remove the pump from its
mounting, and clamp the air motor base (5) in a
vise.
4. Use a strap wrench or pipe wrench on the extension
tube (64) to unscrew it from the base (5). See Fig. 4.
5. Pull the extension rod (57) down as far as it will go,
exposing the displacement rod (8).
6. Use a hammer and punch to remove the roll pin (74)
from the displacement rod (8), and unscrew the
extension rod (57) from the displacement rod.
7. Manually push on the displacement rod (8) to move
the air motor piston (2) up as far as it will go.
Unscrew the cylinder cap nut (29a or 29b). Pull the
nut up. Grip the trip rod (11) with padded pliers, and
unscrew the nut from the rod. See Fig. 4.
8. Remove the six screws (21) that hold the cylinder
(17) to the base. Carefully pull the cylinder straight
up off the piston (2).
9. Use a screwdriver to push down on the trip rod yoke
(22). Always keeping fingers clear of the toggle
assemblies (L), snap the toggles down. Straighten
the lockwires (31) and remove them from the adjust-
ing nuts (30) of the transfer valves. Remove the top
nuts. Unscrew the stems (1) from the grommets (12)
and bottom nuts. Squeeze orange poppets (1) firmly
to check for cracks. See Fig. 5.
10. Grip the toggle rockers (26) with a pliers. Compress
the springs (27), and swing the toggle assembly (L)
up and away from the piston lugs (M), and remove
the parts. Check to see that the valve actuator (13)
is supported by the spring clips (14), but slides eas-
ily into them. See Fig. 5.
11. Remove the trip rod yoke (22), actuator (13), and
trip rod (11). Check the exhaust valve poppets (16)
for cracks.
12. Remove one of the air motor plates (18 or 20). Pull
the piston (2) up out of the base (5). Remove the
throat packing nut (38) and throat seal (6).
CAUTION
In step 7, do not damage the plated surface of the trip
rod (11). A damaged trip rod could cause erratic air
motor operation. Use the special padded pliers
(248198) to grasp the rod.
CAUTION
To avoid damaging the cylinder wall, lift the cylinder
straight up off of the piston. Never tilt the cylinder
while you are removing it.
To remove cracked exhaust valve poppets (16),
stretch them out, and cut them with a sharp knife.