Graco 308-017 warranty Displacement Pump Service, Disassembly

DISPLACEMENT PUMP SERVICE

Disassembly

When disassembling the pump, lay out all removed parts in sequence, to ease reassembly. Refer to Fig 6.

NOTE: Repair Kit 222-773 is available to replace the pis- ton and intake valve seals. For the best results, use all the new parts in the kit. Kit parts are marked with one asterisk, for example (11*).

Repair Kit 222-774 is available to replace the throat packings. For the best results, use all the new parts in the kit. Kit parts are marked with two asterisks, for example (3**).

1.Remove the displacement pump from the air motor as explained on page 9. Place the pump in a vise, with the jaws on the outlet housing (10).

2.Hold the flats of the priming piston rod (24) with a 12 mm wrench. Using a 22 mm wrench, unscrew the priming piston nut (30). Slide the priming piston (25) and piston guide (31) off the rod. Inspect the surfaces of the guide (31) and piston (25) for scoring, wear, or other damage.

3.Loosen the packing nut (2) using the wrench (1 10) supplied, or a hammer and brass rod. Remove the in- take cylinder (23), using an adjustable wrench.

4.Unscrew the intake valve housing (17) from the cylin- der (12), using an adjustable wrench. Pull the hous- ing off the pump. The intake check valve assembly

(S) should slide down the priming piston rod (24) as you remove the housing; if it does not slide easily , firmly tap on the top of the housing (17) with a rubber mallet to loosen.

5.Use an o-ring pick to remove the seal (21) from the intake valve housing (17). Discard the seal; use a new one for reassembly . Pull the intake valve seat (22) out the bottom of the housing (17). If the seat is

difficult to remove, insert a hammer and brass rod through the top of the housing and drive the seat out.Take care not to drop the check valve assembly

(S) as it comes free, and set it aside for later.

6.Push the displacement rod (1) down as far as possi- ble, then pull it and the priming piston rod (24) out of the outlet housing (10) and cylinder (12).

7.Remove the packing nut (2), throat packings (3, 5) and glands (4, 6) from the outlet housing (10). DO NOT remove the fluid outlet nipple (8) and o-ring (9) from the housing unless they need replacement.

8.Unscrew the handle of the bleeder valve (35) from its housing. Clean the threads and the bleed hole in the valve housing. It is not necessary to remove the valve housing from the outlet housing (10).

9.Use a 400 mm adjustable wrench on the flats of the pump cylinder (12) and unscrew the cylinder from the outlet housing (10). Remove the o-rings (11). Inspect the inside surface of the cylinder for wear, scoring or other damage by holding it up to the light at an angle or running a finger over the surface.

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10.Inspect the outer surfaces of the displacement rod

(1)and priming piston rod (24) for wear , scoring or other damage by holding them up to the light at an angle or running a finger over the surface.

11.Use a vise with soft jaws to hold the displacement rod

(1)by its flats. Place a 19 mm wrench on the flats of the piston and unscrew the piston (13) and priming piston rod (24) from the displacement rod (1). Re- move the spacer (33). Disassemble the piston guide

(14)from the piston (13).

12.It is not necessary to remove the priming piston rod

(24)from the piston (13) unless your inspection re- veals scoring, wear, or other damage to either part. To disassemble, place the piston flats in a vise and unscrew the rod, using a 12 mm wrench on the flats.

13.Place the flats of the piston seat (16) in a vise. Using a 13 mm (1/2 in.) dia. brass rod, unscrew the piston guide (14) from the piston seat (16). See Fig 4. Re- move the piston seal (15); always replace with a new one. Inspect the mating surfaces of the piston (13) and piston seat (16) for nicks, scoring or wear.

16BRASS ROD

14

0205

Fig 4

14.To disassemble the intake check valve (S), place the nut (18) in a vise and unscrew the intake valve body (19), using a 28 mm wrench. See Fig 5. Remove the seals (42, 20) from the nut and from the valve body; always replace them with new ones. Inspect the mat- ing surfaces of the intake valve body (19) and seat (22) for wear, scoring, or other damage.

NOTE: The seal (42) is press-fit in the nut (18) and may require cutting to ease removal.

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19

0206

Fig 5

15.Inspect all parts for damage and clean with a com- patible solvent. To reassemble, refer to page 12.