Graco Inc 740, 800-909, 800-906, 735 Pump Service, Valves, Pumping Section, Servicing the Plungers

PUMP SERVICE

WARNING

To reduce the risk of serious bodily injury , including fluid injection, splashing in the eyes or on the skin, or injury from moving parts, always follow the Pressure Relief Procedure Warning before proceeding.

NOTE: The following metric wrenches are needed: M10, M13 and M30. Repair kits are available. Refer to the individual repair sections and the pump parts page for more details. For the best results, use all parts in the kits.

NOTE: There are two dif ferent tool kits to aid in servicing the pump. P/N 800–298 is used to ease installation of packings. P/N 800–271 includes the items in 800–298 and tools to aid in the removal of packing retainers.

Valves

NOTE: For a set of six valves, order P/N 803–664 or 803–666.

1.Remove the hex plug from the manifold using an M30 wrench.

2.Examine the o–ring under the hex plug and replace it if it is cut or distorted.

3.Remove the valve assembly from the cavity; the assembly may come apart.

4.Install the new valve. Install the o–ring and hex plug; torque to 75 ft–lb (103 Nm).

NOTE: Retorque the plug after 5 hours of operation.

Pumping Section

1.Remove the eight capscrews and lockwashers from the manifold using an M13 wrench.

2.Carefully separate the manifold from the crankcase.

NOTE: It may be necessary to tap the manifold lightly with a soft mallet to loosen.

CAUTION

Keep the manifold properly aligned with the ceramic plungers when removing to avoid damage to the plunger or seals.

3.Carefully examine each plunger for any scoring or cracking and replace as necessary.

Servicing the Plungers

NOTE: Plunger repair kit, P/N 803–677 is available to replace retainers, o–rings, washers and backup rings for three cylinders.

1.Loosen the plunger retaining screw five to six turns, using an M10 wrench. Push the plunger towards the crankcase to separate the plunger and retaining screw.

2.Remove the screw from the plunger and examine the o–ring, backup ring and copper bearing/gasket washer. Replace these parts, if necessary, using kit 801–474.

3.Remove the plunger and flinger from the plunger shaft. Clean, examine and replace parts as necessary.

4.Inspect the plunger shaft for oil leakage from the crankcase. If leaking is obvious, replace the oil seals. Otherwise, DO NOT remove these seals as they cannot be reused. An oil seal kit is available to replace the seals.

5.Lightly grease the oil seal, if it is being replaced, and the flinger and replace them on the plunger shaft. Then install the plunger.

6.Lightly grease the retaining screw and the outer end of the plunger. Place the washer, o–ring and backup ring around the screw and install the screw through the plunger. Torque to 14.4 ft–lb (19.5 Nm).

NOTE: If you plan to replace the packings, refer to Servicing the V–Packings.

7.	Lubricate the outside of each plunger	. Slide the
	manifold onto the crankcase, being careful not to
	damage the seals.
8.	Install the capscrews and washers	finger–tight.
	Torque the screws to 21.7 ft–lb (29 Nm) following the
	tightening pattern (Figure 4). Uneven tightening may
	cause the manifold to bind or jam.

5 1 4 7

8 3 2 6

Figure 4

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