Graco 312068M important safety instructions Piston and Cylinder Seals, #28 Pump Size

Piston and Cylinder Seals

Piston Seal and Cylinder Seal Repair Kits are avail- able. See Table 1 on page 17 to order the correct kits for your pump. Also see kit manual 312071.

Repair

Reassembly

CAUTION

To prevent cross-contamination of the equipment’s wetted parts, never interchange component A (isocy- anate) and component B (resin) parts.

1.Install piston rod seal (15); ensure u-cup faces pis- ton rod (28) as shown in FIG. 1.

Disassembly

1.	Relieve pressure, page 3.
2.	Turn OFF the main disconnect and lock out power at
	the source.

18

28

15

TI9823a

3.	Disconnect the pump inlet and outlet lines; see your
	proportioner repair manual. Remove the four screws
	(30) holding the pump outlet flange (26) to the
	hydraulic cylinder. Disconnect pump from drive and
	take pump assembly to a workbench.
4.	Remove the four bolts (8) and washers (5). See
	Parts on page 15.
5.	Remove the flange retainer (27), gasket (17), bush-
	ing (13), and throat seal (29).
6.	Use a soft-faced mallet to help separate pump base
	(23) and outlet flange (26) from cylinder (12).
	Remove crossover tube (24)
7.	Remove piston from cylinder bore. Remove piston
	cap bolt (25), then slide bushing (18) and u-cup seal
	(15) from rod.

FIG. 1: U-Cup Orientation

2.Assemble piston bolt (25) to piston rod (28). Apply supplied thread sealant to piston bolt and tighten. See Torque Specification table for torque according to pump size.

15	28
3	TI9822a
25 1

1 Apply supplied sealant to threads.

#28 Pump Size 28

8. Thoroughly clean all parts in a compatible solvent

and inspect for wear or damage. Replace as

required.

25 18

15 1

r_24f290_312068

FIG. 2: Piston Head and Rod

Torque Specification

Pump Size	Torque
30	130 in-lb (14.7 N•m)
28, 40, 48, 60	22 ft-lb (29.7 N•m)
80, 88, 96, 120, 140	45 ft-lb (60.8 N•m)

312068M 7