PLUNGER AND PACKING
REPLACEMENT
Pump maintenance is vital to keeping your machinery performing at its peak, and an important part of that maintenance is replacing your worn out plungers. Whichever model of plunger pump you're running - Gardner Denver, SPM, BJ Pacemaker, JMAC, Pinion, or anything else - we can help get you all of the parts and tools you need, along with this guide outlining the process for making the change. Still stuck? Let us know, we're more than happy to help!
1 Remove suction cover retainer nut with a Retainer Nut Removal Tool.​
2 Remove any other covers over the top of the plungers to get access to the plunger clamp/extension rod area.
3 Remove the cap screws that hold the plunger clamp, then remove the clamp.
4 Loosen the packing nut to help free the plunger from packing. Then remove the plunger and complete packing assembly through the suction cover opening.
5 Loosen the packing nut to help free the plunger from packing. Then remove the plunger and complete packing assembly through the suction cover opening.
6 Clean and inspect the stuffing box bore to ensure it is clean and all debris is removed. Make sure that the bore is smooth and it is not washed out.
7 Inspect the trim and plungers for damage. Replace if they have significant scoring or poor surface finish.
8 Lubricate packing set with standard packing lubrication oil.
9 Install trim and packing one ring at a time, pulling each component (spacer, head ring, pressure ring, and lantern ring) completely against the shoulder in the fluid end.
10 With the plunger removed, tighten the packing nut hand tight plus 1/4 turn to ensure that the packing is seated.
11 Draw a line with a marker from the stuffing box to the gland nut (Figure 1).
12 Back off the packing nut 3/4 to 7/8 of a turn, coat the plunger with a thin film of oil and install the plunger by pushing it into the stuffing box bore. Do not beat the plunger with a hammer (Figures 2, 3, 4).
13 Tighten the packing nut to realign with the mark on the stuffing box. This alignment mark also provides a visual indicator if the gland nut should back off during operation or transportation (Figure 5).
14 Inspect the clamp surfaces, plungers, and extension rods for cleanliness. Then install the clamp and tighten screws.
15 Replace the seals on the suction cover, install the suction valve spring retainer if necessary, and then tighten the suction cover retainer nut.
Fig. 1 Alignment mark with packing hand tight plus 1/4 turn.
Fig. 2 Gland nut backed off.
Fig. 3 Installation of plunger.
Fig. 4 Installation of plunger by pushing.
Fig. 5 Gland nut tightened back to alignment mark.