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Seal Replacement
The seal assembly in 4100/4120 pumps can be changed without disassembly of the rest of the pump.
• Place the pump in a vise with the shaft facing up so that one jaw grips across the two ports. Do not tighten excessively as the
pump housing may become distorted.
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Inspect the shaft at the keyway, flat or tang. Any burrs will interfere with removal of the housing plug and bearing assembly.
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Remove the housing plug with a face-type spanner wrench, available from Tuthill as part number 0L506.
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Remove the seal from the shaft. The rubber boot will be bonded to the shaft, so it is necessary to push down on the seal
to break this bond. Grasp the metal outer shell with any suitable device and pull the seal assembly upward. Remove the
spring and washer.
•
Models 4101/4121, 4102/4122, 4103/4123, and 4104/4124 have a retaining ring on the shaft to back up the seal assembly.
Do not remove this retaining ring unless you are completely disassembling the pump. Models 4105/4125 and 4108/4128
do not have a retaining ring. A step on the shaft is used as the seal backup.
• Remove the stationary seal face from the housing plug by pressing out from the opposite side.
•
If damaged, remove the o-ring from the OD of the housing plug.
• Clean all parts thoroughly using great care to eliminate all dirt.
•
Oil the shaft with suitable lubricating oil. (If the pump has an EPR seal, apply a siliconbased lubricant instead.)
• Apply the appropriate lubricant to the inside of the new seal assembly.
• Install the seal head
•
For standard full-length shafts with flat and/or keyway place seal assembly on the pump shaft
•
Push seal down with your fingers to a position approximately half way down the shaft
•
For modification “A” tang shafts use a tapered plastic sleeve available from Tuthill (part # 1LPF531-7010)
• Lubricate the sleeve and place seal assembly on the sleeve
•
The tapered end of the sleeve fits into the spring end of the seal assembly
• Place the slotted end of the sleeve on a bench
•
Press down on the carbon face of the seal with your fingers and slide the seal to about the midpoint on the sleeve
• Place the slotted end of the sleeve over the tang on the pump shaft
• Line up the outside diameters of the sleeve and shaft by eye
•
Push seal down with your fingers so that it passes from the sleeve to a position approximately halfway down the shaft.
• Press the stationary face completely into the housing plug. The lapped surface must be up. Protect this lapped surface by
covering it with a piece of paper when pressing down on the face. Use your fingers for this operation.
•
Place a new o-ring on the OD of the housing plug, if required, and lubricate.
• Lubricate the carbon face liberally.
• Re-assemble the housing plug into position over the pump shaft. Do not nick the seal face by hitting the pump shaft. Tighten
the housing plug with the spanner wrench. The seal will automatically be positioned by this operation.
•
If the pump is equipped with a ball bearing (modification K), press the bearing onto the shaft. Press on the bearing inner
race with a suitable sleeve. Do not hammer into position or press on the bearing outer race.
•
Check pump for free rotation by turning the shaft with a suitable wrench. There will be a definite resistance to turning
because of the seal load. The pump must turn freely without binding.