Plunger Pump Maintenance

Replacing Plunger & Installing Packing

Detailed instructions on how to replace and install a pump plunger and pump packing.

a) Remove valve chamber cover and yoke assembly from suction side of pump. It may be necessary to remove suction air chamber if equipped.

b) Rotate main shaft until plunger is in bottom position.

c) Tighten gland bolts to lock plunger into stuffing box.

d) Remove bolts holding stuffing box to pump body.

e) Rotate main shaft until plunger and stuffing box assembly clears pump body.

f) Swing plunger and stuffing box assembly toward suction side of pump. Brace connecting rod to hold assembly in outward position.

g) Loosen gland bolts. Slide stuffing box off plunger.

h) Remove gland and packing. Clean packing cavity.

i) Install new packing making sure joints are staggered at 90 degree intervals:

For “V” Style Packing:
- Bottom Ring – Flat side down
- Center Ring – Crowned side up
- Top Ring – Flat side up

j) Replace gland bolts or studs and nuts. Do not tighten.

k) Replace plunger:
- Remove jam nuts (located inside plunger, holding crosshead to plunger. Do not remove set screws holding wrist pin)
- Remove cap screws under plunger (on) PE 61A, cap screws are located inside the plunger
- Remove plunger
- Remove drain rod and install in new plunger
- Install new plunger. Reverse above procedure using new sealing washers supplied (plunger to crosshead cap screw)

l) Lubricate inside surface of stuffing box and packing. Also outside surface of plunger. Use available oil (motor or gear oil)

m) Slide stuffing box, packing and gland assembly on plunger. Tighten gland bolts to hold stuffing box in position.

n) Remove brace, swing assembly over pump body

o) Check “O” ring gasket. IMPORTANT: Make sure it is correctly positioned in stuffing box groove.

p) Rotate main shaft to properly position stuffing box on pump body. Replace and tighten stuffing box bolts.

q) Loosen gland bolts. (Do not remove)

r) Fill plunger to center of wrist pin with SAE 90 gear oil.

s) Rotate main shaft at least one complete revolution (by hand) to make sure that the pump operates freely.

t) Replace valve chamber cover, yoke assembly and air chamber.

u) Pour SAE 90 gear oil around plunger.

v) Turn on power. Adjust packing gland just enough to prevent excessive leakage. IMPORTANT: Tighten gland bolts slowly and evenly to avoid damage to packing and plunger. A slight flow of liquid from the stuffing box when the pump is running keeps the packing in good condition. Slight gland adjustment may be required until the packing is properly seated.