Air Motor
carefully pry the handle off of the detents.
11. Remove the handle. A screwdriver can be used to
12. Using a 5 mm hex key, remove the air motor tie rod
screws (43).
13. Remove the air motor base assembly and inspect.
14. Remove the snap ring (38) in order to replace the guide
bushing assembly (39) located in the air motor base
assembly (40). Inspect the guide bushing assembly and
replace if required.
15. Remove the air motor cylinder (37) and check the air
motor cylinder o-rings (36). Replace if necessary,
16. Inspect the air motor piston o-ring (29) and replace if
showing wear.
17. Inspect the transfer tubes (41) and transfer tube o-rings
Air Motor – Trip Rod
(42). Replace if worn or damaged.
18. Remove the valve head end cap bolts (7) and remove
the valve head end cap (8).
19. Inspect the dampening spacer (11) and replace if
necessary.
20. Remove the trip retainer nut (12) and remove the
piston/rod assembly from the motor.
21. Unscrew the air motor piston rod (35) from the piston
(30). Be careful not to drop the o-ring, guide ring, and
retainer (31, 32, 33). Replace these three items if worn.
22. Inspect the trip rod assembly (34) and replace if
required. Lubricate the trip rod with high quality grease
such as Binks part no. 41-4458-K.
23. Reassemble the trip rod assembly into the piston rod
and piston.
24. Also, at this time, inspect the trip rod u-cup seal (28),
spacer (27), and trip rod guide bushing (25). The guide
bushing is held in place with a retaining ring (26).
Air Motor – Spool Valve
Inspect these items and replace if required.
25. In order to service the spool valve assembly, the detents
must be removed. First, remove the air dampening
baffle (44) to expose the spring housing set screws (23,
24).
26. Loosen the spring housing locknut (24) and place
thumb over the end of the detent bearing bushing (22).
Then loosen the spring housing set screw (23). The
bearing bushing will then slide out of its bore.
27. With the detent components (18, 19, 20, 21, 22)
removed, the pilot valve carrier assembly and (14) and
spool valve assembly (16) can be removed and
inspected. Replace the spool valve assembly if required.
SERVICING THE Binks 4/12 BARE PUMP
28. With the spool valve and pilot valve carrier assembly in
place, reassemble the detent components (18, 19, 20,
21, 22). First install the toggle (18) and the toggle
bearing (19) into the bore. Be sure that the toggle is
fitted to both the carrier assembly (14) and the toggle
bearing (19)
29. Lubricate the valve spring (20) with high quality grease
and assemble the spring and the valve spring guide (21)
into the bearing bushing (22).
30. Insert the bearing bushing containing the spring and
guide into the bore. Take care to be sure that the toggle
bearing (19) that was previously installed is guided into
the bearing bushing (22). A screw driver can be used to
help align the toggle bearing. See picture below. Hold
up the toggle bearing with the screw driver and guide
the bearing bushing into the bore with your other hand.
The bearing bushing should slide in easily.
31. After the bearing bushing is completely inserted, tighten
Air Motor – Re-Assembly
the spring housing set screw (23) and locknut (24).
32. Reinstall the piston/trip rod assembly and tighten the
trip rod retainer nut.
33. Install the upper air cylinder o-ring (36) and air motor
cylinder (37).
34. Position the transfer tubes (with o-rings) in the air
motor base assembly (40). Be sure that the guide
bushing assembly (39) is in place.
35. Install the lower air cylinder o-ring, and reassemble
using the air motor tie rods (43).
36. Replace the air dampening baffle (44) and reassemble
the valve head end cap (8) with the valve head end cap
screws (7).
Safety Valve
37. Replace the handle.
38. Replace the safety valve (45) if pump exceeds normal
operating pressure.
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