Graco 306981AD important safety instructions Displacement Pump Service, Disassembly, Reassembly

Service

Displacement Pump Service

Disassembly

When disassembling the pump, lay out all removed parts in sequence, to ease reassembly. Refer to Fig. 5.

NOTE: Repair Kit 235635 is available. For the best results, use all the new parts in the kit. Parts included in the kit are denoted with an asterisk, for example (17*).

Clean all the parts thoroughly when disassembling. Check them carefully for damage or wear, replacing parts as needed.

1.Remove the displacement pump from the air motor as explained on page 13.

2.Unscrew the intake valve housing (33) from the outlet housing (35). If it is difficult to remove, squirt penetrating oil around the threads and gently tap around the valve housing with a plastic ham- mer to loosen it. See Fig. 5.

3.Remove the ball stop pin (29), o-ring retainer (31), o-ring (30), guide (32) and ball (28) from the intake valve housing (33).

4.Loosen the packing nut (36). Push the displace- ment rod (26) down as far as possible, then pull it out the bottom of the outlet housing (35).

5.Secure the flats of the displacement rod (26) in a vise. Screw the piston stud (34) out of the rod. Re- move the ball (17), retainer (22), packings (18, 23) and glands (24, 25).

6.Remove the packing nut (36), throat packings (18, 23) and glands (24, 25) from the outlet housing (35).

7.Inspect all parts for damage. Clean all parts and threads with a compatible solvent before reassem- bling. Inspect the polished surfaces of the dis- placement rod (26) and sleeve (20) for scratches, scoring or other damage, which can cause prema- ture packing wear and leaking. To check, run a finger over the surface or hold the part up to the light at an angle. Be sure the ball seats of the pis- ton (R) and intake valve housing (S) are not chipped or nicked. Replace any worn or damaged parts.

NOTE: If the sleeve (20) needs replacement and is hard to remove, contact your Graco distributor.

Reassembly

1.Lubricate the throat packings and install them in the outlet housing (35) one at a time as follows, with the lips of the v-packings facing down: the male gland (24*), one leather v-packing (18*), one PTFE (23*), one leather (18*), one PTFE (23*), one leather (18*), one PTFE (23*), and the female gland (25*). Install the packing nut (36) loosely. See the Throat Packing Detail in Fig. 5.

2.If you removed the sleeve (20), reinstall it in the outlet housing (35), making sure to replace the gasket (19*). Be sure the tapered end of the sleeve faces down, toward the pump intake.

3.Lubricate the piston packings and install them onto the piston stud (34) one at a time in the following order, with the lips of the v-packings facing up: the female gland (25*), one PTFE v-packing (23*), one leather v-packing (18*), one PTFE (23*), one leath- er (18*), one PTFE (23*), one leather (18*), the male gland (24*), and the packing retainer (22). See the Piston Packing Detail in Fig. 5.

4.Use thread sealant on the piston stud (34). Install the piston ball (17*) on the piston and screw the piston valve assembly into the displacement rod (26). Torque to 55–65 ft–lb (74–88 N.m).

5.Insert the displacement rod (26) into the bottom of the outlet housing (35), being careful not to scratch the sleeve (20). Push the rod straight up until it protrudes from the packing nut (36).

6.Install the ball (28*), guide (32), o-ring (30*), retain- er (31), and ball stop pin (29) in the intake valve housing (33). Apply thread lubricant and screw the intake housing into the outlet housing (35). Torque to 55–65 ft–lb (74–88 N.m).

7.Reconnect the displacement pump to the air motor as explained on page 13.

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