Graco Inc GX-7 400, 311321H, GX-7A Replace End Cap and Air Piston Assembly, GX-7 DI Shown

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Replace End Cap and Air Piston Assembly

	End Cap
	Spacer
Piston Assembly
		Rear
Front U-Cup Seal	Piston	U-Cup
	Piston	Seal
		Seal

Spring

Socket Head Cap Screw

Cylinder Clamp

GX-7 DI Shown

FIG. 25: GX-7 DI End Cap and Air Piston Assembly

1.Clean gun according to Clean Spray Gun Procedure, page 20.

2.Loosen rear packing nut 1-2 turns.

3.Push safety stop partially forward, rotate counterclockwise, and slide safety stop off air cylinder.

4.Remove valving rod. See Remove Center- line Components, page 22.

5.Disconnect air supply from gun.

6.Remove rear head cap screw and cylinder clamp from handle.

7.Remove end cap from air cylinder.

8.Inspect end cap o-ring. Replace if dam- aged. Install new end cap o-ring after lightly coating it with Lubriplate grease.

9.Inspect rear U-cup seal or o-ring for dam- age. Replace if necessary. If removed,

Repair

ensure “cup” faces front of air cylinder when replacing.

10.By hand, pull piston assembly out of air cyl- inder and inspect o-ring for damage. Replace if necessary. Apply Lubriplate grease prior to installation.

11.If air was escaping around piston rod dur- ing operation, replace front u-cup seal or o-ring. Apply Lubriplate grease and ensure “cup” faces rear of air cylinder.

12.Insert piston and rod assembly into air cyl- inder. Take care to not damage front cup seal as rod passes through.

13.Insert piston spring. (For GX-7 DI models, also insert piston spacer.)

14.Reinstall end cap into air cylinder.

15.Retighten rear socket head cap screw and cylinder clamp to handle.

16.Reinstall valving rod. Connect valving rod to draw bar. Lubricate and thread into end cap.

17.Adjust valving rod; see Valving Rod Adjustment, page 16.

18.Slide safety stop onto rear of air cylinder. Push safety stop partially forward and rotate clockwise to set to OPEN.

19.Set safety stop to CLOSED (SERVICE).

20.Tighten rear packing nut.

311321H

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Image 25

Contents 311321H Important Safety InstructionsGX-7 Models ContentsPersonal Protective Equipment Fire and Explosion Hazard Pressurized Aluminum Parts Hazard Model GX-7A Overall ViewModel GX-7 DI Locknut Model GX-7Valving Rod Rear Stop Gun Block Air Cap Valve TriggerGX-7A Centerline Components Centerline ComponentsGX-7 400 Centerline Components GX-7A Mixing Module Mixing ModuleOperation Basics Safety PositionIsocyanate Hazard Keep a and B Components SeparateAir Hose Connection Disengage Safety StopConnect Air Hoses Disconnect Air HosesCoupling Block Installation and RemovalManual Valves Optional Configuration Air Inlet ConfigurationRemove Coupling Block Do not Overtighten Mixing Module and PCD InstallationGX-7A and GX-7 400 Models Only Valving Rod AdjustmentGX-7 DI Model Only Initial Set Up Daily Shutdown Daily Start-upTrigger Gun Pressure Relief ProcedureGun Service Kits MaintenanceClean Spray Gun Procedure Flush Gun Repair Service Screen ScrewRemove Centerline Components Remove valving rod. Rod Draw Bar Valving Rod Install Centerline Components GX-7 DI Shown Replace End Cap and Air Piston AssemblyReplace Trigger Valve O-Ring Replace Trigger Valve O-RingsUnthread Cap from PCD Body Clean Mixing ModuleInstall Mixing Module Install Mixing ModuleGX-7A Model Shown Clean Pattern Control DiscParts GX-7A Model Final AssemblyNo. Part No. Description GX-7A Model Final AssemblyModule see GX-7A Mix Mod GX-7 DI Model Final Assembly Module see GX-7 DI Model Specifications , GX-7 DI Model Final AssemblyNo. Part No. Description Qty GX-7 400 Model Final Assembly Module Kit , GX-7 400 Model Final AssemblyGX-7A Model Handle Assembly Description GX-7 Model Handle AssemblyGX-7 DI Model Handle Assembly Description Qty GX-7 DI Model Handle AssemblyGX-7 400 Model Handle Assembly GX-7 400 Model Handle Assembly All models Coupling Block AssemblyGX-7A Mix Module Kit SpecificationsTip Set-Up Chart for GX-7A ModelGX-7 400 Mix Module Kit Module Kits Cleanout Drill Iso PortQuantity In/mm Module Only Size RefTip Kits for GX-7 400 Gun No. Ref Quantity Set-up Chart for GX-7 400 ModelModule/Tip Data for Chemical Sprayed at 2500 PSI Output GX-7 DI Model SpecificationsPattern Lbs/min Round Spray PatternTool Kits Tip KitsFor GX-7A and GX-7 DI Models Round Tip Kits Size QuantityCategory Data Technical DataGraco Standard Warranty