SERVICE

Piston￿ Removal￿ and￿ Repair

8. Install￿ the￿ new￿ packing￿ (27)￿ and￿ guide￿ (26)￿ in￿ the

1.

To￿ disconnect￿ the￿ fluid￿ hose￿ (31)￿ from￿ the￿ covergun￿ body￿ (1);￿ screw￿ the￿ guide￿ in￿ loosely.

 

plate￿ (41),￿ screw￿ the￿ nut￿ (34)￿ off￿ the￿ adapter￿ (35).

DO￿ NOT￿ fully￿ tighten￿ the￿ guide￿ (26)￿ yet.￿ The

 

See￿ Fig￿21.

NOTE:

 

 

guide￿ must￿ be￿ loose￿ to￿ avoid￿ damaging￿ the

 

 

 

2.

Note￿ the￿ position￿ of￿ the￿ trigger￿ adjusting￿ nut￿ (24)￿ for

packing￿ (27)￿ when￿ pushing￿ the￿ piston￿ shaft

through￿ the￿ guide.

 

reinstallation,￿ then￿ screw￿ it￿ off￿ the￿ piston￿ ￿ shaft.

 

 

 

 

 

 

9. If￿ replacing￿ the￿ u￿cup￿ packing￿￿(37),slide￿ it￿ onto￿ the

3.

Remove￿ the￿ screws￿ (61)￿ and￿ lock￿ washers￿ (82)￿ frompiston￿ (42)￿ so￿ the￿ lips￿ of￿ the￿ packing￿ will￿ face￿ to;

 

the￿ cover￿ plate￿ (41).￿ Remove￿ the￿ cover￿ plate￿ (41),wards￿ the￿ front￿ of￿ the￿ gun￿ when￿ the￿ piston￿ is￿ in;

 

spring￿ (38),￿ and￿ retainer￿ cap￿ (74).

stalled.￿ Then￿ install￿ the￿ buna;n￿ o;ring￿ (30)￿ and

 

 

4.

Unscrew￿ and￿ remove￿ the￿ air￿ valve￿ guide￿ (26)￿ andVitonr￿ o;ring￿ (79)￿ on￿ the￿ piston.

 

needle￿ packing￿ (27)￿ from￿ the￿ gun￿ body￿ (1),

10. Install￿ the￿ piston￿ assembly￿ into￿ the￿ gun￿ body￿ (1),

 

 

5.

 

being￿ careful￿ not￿ to￿ damage￿ the￿ piston's￿ lip￿ seal.

Push￿ on￿ the￿ end￿ of￿ the￿ piston￿ shaft,￿ and￿ remove￿ the

 

piston￿ assembly.

11. Install￿ the￿ retainer￿ cap￿ (74)￿ into￿ the￿ cover￿ plate￿ (41).

 

NOTE: DO￿ NOT￿ remove￿ the￿ u;cup￿ packing￿ (37)￿ from

12. Install￿ the￿ cover￿ plate￿ (41),￿ spring￿ (38),￿ and￿ retainer

the￿ piston￿ shaft￿ except￿ to￿ replace￿ it￿ as￿ removalcap￿ (74)￿ with￿ the￿ screws￿ (61)￿ and￿ lock￿ washers￿ (82). will￿ damage￿ this￿ packing.

13. Actuate￿ the￿ trigger￿ and￿ tighten￿ the￿ air￿ valve￿ guide

6. Clean￿ and￿ inspect￿ parts￿ for￿ wear￿ or￿ damage.￿ Re;(26)￿ with￿ a￿ wrench. place￿ parts￿ as￿ needed.

7. When￿ reassembling￿ the￿ piston￿ assembly,￿ lubricate14. Screw￿ the￿ trigger￿ adjusting￿ nut￿ (24)￿ onto￿ the￿ piston shaft￿ to￿ its￿ previously￿ noted￿ position.

the￿ o;rings￿ (30￿ &￿ 79)￿ and￿ the￿ u;cup￿ packing￿ (42)￿ on

the￿ piston￿ with￿ petroleum￿ jelly.￿ Pack￿ the￿ spring￿ (38)

15. Connect￿ the￿ fluid￿ hose￿ (31)￿ to￿ the￿ adapter￿ (35).

with￿ petroleum￿ jelly.￿ Apply￿ Teflon￿ tape￿ to￿ the￿ air￿ valve guide￿ (26).

KEY

1

Gun￿ Body

34

Nut

42

Piston

 

24

Trigger￿ Adjusting￿ Nut

35

Adapter

61

Screws

 

26

Air￿ Valve￿ Guide

37

U;Cup￿ Packing

74

Retainer￿ Cap

 

27￿

Needle￿ Packing

38

Spring

79

Viton￿ O;Ring

42

30

Buna;n￿ O;Ring

41

Cover￿ Plate

82

Lock￿ Washers

 

31Fluid￿ Tube

37

7974

141

3538

Pack￿ with lubricant

30

Apply

 

Teflon

 

tape

61

26

24

82

27

3134

Fig￿ 21

24 307-712

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Graco Inc 307-712, PRO 5000, 218-745 manual Piston Removal and Repair