SELF-ADJUSTING PACKING

UPRIGHTS

Make sure the O-ring starts in evenly and is not pinched

15. Push the piston into the cylinder bore until

or cut during assembly.

retainer makes contact with the cylinder.

NOTE

16. Work the retainer into position with a steady,

With the bushing seated in the

even pressure.

retainer and a new packing set in

place, the packing may extend

CAUTION

beyond the end of retainer about 1/16

Make sure the O-ring and back-up

of an inch. (Fig. 36)

ring are not damaged as they pass

the chamfer of the cylinder bore.

17. Turn washer into the cylinder a few turns. Push

piston back and forth a few times to eliminate any slight

mis-alignment. Turn threaded washer all the way into

the cylinder. Tighten set screw.

F. INSTALLATION

Use reverse of removal procedure. Refer to UPRIGHT

ADJUSTMENTS for adjustment procedures.

SELF-ADJUSTING PACKING

Figure 36.

The following instructions should be explicitly followed to

obtain maximum benefit from this type of packing.

(Figs. 34 and 35)

8. Push bushing and retainer assembly on the

piston rod from the piston end of the rod. Pushing from

1. The stack height (A), Figures 37 and 38, of the

the opposite end may damage packing lips.

packing should be such as to fit just snug in the installed

position. There should not be any excessive preloading

of the packing. However, the bushing may extend

9. Place flat piston half in position on the rod.

approximately 1/16 inch beyond the retainer, especially

Install packing on the remaining half, with lips away

when a new packing set is installed. (Fig. 36) The

from the flange.

initial sealing action of the packing is provided by

dimensional tolerances. Therefore, when installing a

10. Place O-ring on rod, at a position halfway

new packing set, the packing should extend

between rod threads and piston half.

approximately 1/8 inch beyond the bushing. (Fig. 39)

Under no circumstances should the packing height be

11. Slide piston half with packing on the rod until

even with the end of bushing. It should always protrude.

contact is made with the O-ring.

This insures that the packing lips will seal on the initial

surge.

12. Make sure the O-ring starts in the piston

counterbore evenly and continues to move in as the

2. Any excessive preloading of the packing will

piston is pushed into position next to the previously

give a corresponding shortening of the packing life.

installed piston half.

3. The self-adjusting feature of the retainer

13. Secure piston in position with nut.

assembly or piston will give extra sealing action at the

14. Slide threaded nut toward the piston end until

retainer and bushing contact the piston.

B-188