Displacement Pump Repair

WARNING

INJECTION HAZARD

To reduce the risk of serious injury, whenever you are instructed to relieve pressure, follow the Pressure Relief

Procedure on page 9.

NOTE: Packing Repair Kit 235–703 is available. Refer- ence numbers of parts included in the kit are marked with an asterisk, i.e., (121*). For the best results, use all the new parts in the kit, even if the old ones still look good.

NOTE: To minimize down time, and for the best sprayer performance, check the motor brushes (see page 20) and clean the transducer (see page 31) whenever you re- pack the pump. Replace these parts as needed.

Removing the pump (See Fig. 17.)

2.Align the hole in the rod (107) with the connecting rod assembly (15). Use a screwdriver to push the retaining spring (18) up and push in the pin (17).

Push the retaining spring (18) into place around the connecting rod.

3.Reconnect the suction and drain hoses (32,33). Install the front cover (13).

4.Tighten the packing nut (102) just enough to stop leakage, but no tighter. Fill the packing nut/wet-cup 1/3 full with Graco TSL. Push the plug (123) into the wet-cup.

1.Flush the pump, if possible. Relieve pressure. Stop the pump with the piston rod (107) in its lowest position, if possible. To lower the piston rod manu- ally, rotate the motor fan blades.

2.Loosen the swivel nut on adapter (38) and remove suction hose (32). While pushing in on the collar of elbow (36), pull out and remove drain tube (33).

NOTE: If repairing only the intake valve assembly, go to Intake valve repair, page 23.

3.Use a screwdriver to push the retaining spring (18) up and push out the pin (17).

4.Loosen the screws (21). Remove the pump (20).

Installing the pump (See Fig. 18 and 19.)

1. Mount the pump on the drive housing. Tap it into

107

20 21

		120
		*122
		*121
	36	*119
	118	*119
	118

		Torque to
		50 ft–lb (68 N.m)
		50 ft–lb (68 N.m)

2Apply sealant (42d)

the alignment pins with a soft hammer. Tighten the

screws (21) to 50 ft-lb (68 N.m).

WARNING

MOVING PARTS HAZARD

Be sure the retaining spring (18) is firmly

in the groove all the way around, to pre- vent the pin (17) from working loose due

to vibration. See Fig. 18.

Fig. 17

123

4654

If the pin works loose, it or other parts could break off due to the force of the pump action. These parts could be projected into the air and result in serious injury or property damage, including the pump con- necting rod or drive housing.

		Torque to
		50 ft–lb (68 N.m)
		50 ft–lb (68 N.m)

21	102
Fig. 18	4655

390sts, 231-353, 308-548 specifications

Graco Inc. has established itself as a leader in fluid handling equipment, and the Graco 308-548, 231-353, and 390STS models exemplify this commitment to innovation, efficiency, and reliability. These models are designed for high-performance applications in various industries, including automotive, construction, and manufacturing.

The Graco 308-548 is engineered with a powerful motor and advanced pump technology, providing user-friendly operation and outstanding reliability. Its design allows for easy maintenance, minimizing downtime and increasing productivity. The adjustable pressure setting ensures optimal performance for different materials, making it a versatile choice for spray applications. Its lightweight construction and portability enhance usability, allowing operators to move the unit with ease.

On the other hand, the Graco 231-353 model is known for its advanced airless technology, which enables users to achieve a smooth and even finish without the need for thinning. This model is equipped with an efficient pump that delivers consistent material flow, ensuring high-quality results in every application. A notable feature of the 231-353 is its ability to handle a wide range of coatings, including paints, stains, and sealers, making it ideal for both interior and exterior projects.

The Graco 390STS stands out in this lineup with its robust design and powerful performance, suitable for larger scale projects. It incorporates SmartControl technology, which provides precise pressure control and consistent spray patterns, contributing to an efficient work process. The ergonomic design emphasizes operator comfort, reducing fatigue during extended use. Additionally, the 390STS supports a variety of spray tips, allowing for customization based on specific job requirements, further enhancing its versatility.

All three Graco models feature durable construction, capable of withstanding rigorous job site demands. They are built with high-quality materials that resist corrosion and wear, ensuring longevity and reducing the total cost of ownership. The ease of use and intuitive controls minimize the learning curve for new users, making these models accessible to both professionals and DIY enthusiasts alike.

In conclusion, Graco Inc. continues to push the boundaries of fluid handling technology with the 308-548, 231-353, and 390STS models. Their powerful performance, advanced features, and user-friendly designs make them standout choices for anyone in need of reliable spray equipment.

Graco Inc 308-548, 390sts, 231-353 manual Displacement Pump Repair, Removing the pump See Fig

Models: 390sts 231-353 308-548