FMC Plunger Pumps Page - Cross Pump & Equipment (304) 925-2116

Servicing The M14 Power End

The plunger rod oil seals retain oil in the power frame (1) and prevent dirt, water, or other contaminants from entering the power frame (1) by way of the plunger rods. The fluid end need not be disturbed to perform this procedure.
Bleed off all pressure inside pump fluid end before starting any service work. Check to insure that the power is locked out.
Unbolt the plunger clamps (14) and remove them from the plungers (42) and plunger rods (6).
Rotate the crankshaft (2) by hand until one of the plungers (42) is moved fully forward, toward the fluid cylinder (34), and the plunger rod (6) is fully retracted.
Slide the deflector shield (21) off the end of the plunger rod (6).
Unbolt the four cap screws (16) holding the plunger rod seal housing (15) to the power frame (1). If needed the cap screws (16) can be used to jack the seal housing (15) away from the power frame (1) using the two tapped holes provided. Pull the seal housing (15) over the end of the plunger rod (6) and out of the cradle. Repeat these three steps for the other two seal housings.
Remove the three seals (24) and the o-ring (22) from the seal housing (15). Note the orientation of each seal prior to removing it.
Inspect the plunger rod (6) at this time. If it is scored or damaged in any way it must be removed. To remove the plunger rod (6) unscrew it from the crosshead (5). A new plunger rod (6) is screwed into the cross head (5) and torqued per the Fastener Torque Requirements section.
Install a new o-ring (22) and new seals (24) in the seal housing (15) in the same orientation that they were originally.
Replace the seal housing (15) in the power frame cradle over the plunger rod and into position in the counterbore. Tap into position using a rubber mallet. The four cap screws (16) can be used to evenly draw the seal housing (15) into place. Take care to avoid folding the seal lips back when they are pushed over the plunger rod (6) and cutting the o-ring (22) when the seal housing (15) is installed in the power frame (1). Apply a small amount of motor oil on the plunger rod and the seal bore in the power frame (1) to aid this process and provide lubrication to the seals (24) during start-up.