Inspect all parts for excessive wear or for any nicks or burrs. Remove nicks
or burrs using an Emery cloth or a fine file. Replace any parts that are badly worn or damaged.
It is recommended that gaskets and o-rings be replaced whenever your
pump is reassembled. When reinstalling pump components after disassembly, refer
to the table in the manual accompanying your pump for hardware torque specifications.
It is recommended that the bearing be replaced during maintenance;
however, if the bearing must be reused, rotate the bearing by hand to
check for roughness or binding. If rotation is rough, or there is any
side-to-side movement between the inner and outer races, the bearing must be replaced.
The bearing is permanently sealed and requires no additional lubrication,
except a coating of light oil on external surfaces to ease reassembly.
External surfaces must be kept free of all dirt and foreign material.
Failure to do so could damage the bearing or its mating surfaces.
Coat the bearing with light oil. The bearing tolerance provides a light press fit
into the rotor adjusting sleeve. Replace the rotor adjusting sleeve if the proper
fit is not achieved. When replacing bushings, lightly oil the OD of the
replacement bushing before installation. If your pump is equipped with carbon
graphite bushings, be very careful when installing the bushings. Graphite is
extremely brittle and will crack if improperly installed. Use a press to
install the bushing with one continuous motion until the bushing is fully seated.
Stopping in mid-stroke will cause the bushing to crack. After installation,
check the bushing for cracks. When installing high-temperature graphite bushings,
heat the part that receives the bushing to 500 degrees Fahrenheit.
This will allow easier installation with less chance of breakage.
Position the back head on the bed of a press with the rotor end facing up.
Use a suitably-sized dowel to press the assembled shaft bushing sleeve and shaft
bushing into the back head until fully seated. Install a new gasket over the
shaft bushing sleeve. Position the balance hole as shown and secure the
back head assembly to the housing with the cap screws. Secure the foot bracket
to the back head with the previously removed hardware. Inspect the rotor and
shaft assembly for excessive wear, scoring or scratches along the shaft
sealing surface. If replacement is required, the shaft and rotor must be
replaced as an assembly. Small scratches can be dressed with a fine file or Emery cloth.
Replace the rotor and shaft assembly or any other parts if wear or
damage is extensive. Slide the rotor shaft assembly into the housing and back head.
Use caution not to scratch or chip the ID of the shaft bushing.
Clean the seal cavity and shaft with a cloth soaked in fresh cleaning solvent.
It is recommended that replacement packing rings pre-cut to the correct width and
length and packaged in sets be ordered from your Gorman-Rupp Distributor or the factory.
Lubricate the new packing rings with nondetergent oil before installation.
For best performance, do not stretch or separate packing braids.
Install the gasket first, then install the first packing ring.
Push each individual packing ring into the seal bore and compress it using a
blunt-ended sleeve and mallet.
Each successive layer must be compressed and rotated by 90 degrees to prevent excessive leakage.
Be sure the lantern ring, if equipped, is aligned with the lubrication port when
the packing is fully compressed.
Add enough packing to fill the seat sleeve to within 3/8 inch of the end.
Position the split gland halves on the shaft and install the gland retainers
over the ends of the split gland.
Install the hardware and tighten in an alternating pattern until the gland nuts
begin to compress the packing.
Do not overtighten the gland nuts. If the packing rings are compressed too tightly,
they may cause the shaft to overheat and damage the pump.
If the idler pin was removed, apply pipe sealant to the OD of the replacement
idler pin and the ID of the idler pin bore in the head. Position the pin in the
head with the chamfered side toward the head and the milled flat side facing the crescent.
Use a press to install the pin into the head. When properly installed,
the pin will be positioned 1/100 inch below the surface of the crescent.
Lightly oil the ID of the idler and use a press to install the idler bushing in the idler.
The bushing should be centered at both ends of the idler.
Place the head on a flat surface. Lightly oil the idler bushing. Install the idler
assembly on the pin. Spin the idler to make certain that it moves freely on the pin.
Install the head gasket and/or o-ring over the head.
Carefully position the head and idler against the housing and engage the idler
and rotor shaft assembly. Turn the rotor shaft until the idler and rotor teeth engage.
Do not force. Slide the head into the housing assembly. Rotate the head
until the groove in the head matches the groove in the housing. Secure the head to
the housing with the cap screws.
Clean the rotor adjusting sleeve and all component parts as previously described.
Inspect the parts for wear or damage and replace as necessary. Use thumb pressure
to install the bearing in the rotor adjusting sleeve until it bottoms out on
the shoulder of the rotor adjusting sleeve. If equipped, install the bearing
retaining cap and secure it to the rotor adjusting sleeve with the hardware.
Tighten the cap screws until snug, then fully tighten in a cross sequence.
Loosen the socket head set screws. Slide the rotor adjusting sleeve over the shaft.
Screw the rotor adjusting sleeve into the back head until the rotor
bottoms against the head.
It is recommended that a new bearing lock washer be installed any time the
rotor adjusting sleeve is disassembled. Reuse of an old lock washer may create a
preload condition on the bearing, resulting in premature bearing failure
Install a new bearing lock washer and screw the bearing lock nut onto the shaft until tight.
Align one of the slots in the locknut with one of the tabs on the lock washer
and use a hammer and punch to bend the tab on the lock washer into the slot on the lock nut.
For more information on pump hydraulics, equipment or application engineering,
watch Gorman-Rupp's YouTube Channel, and visit us at GRPumps.com