51270-Series
Service Instructions
Disassembly - Clutch Unit
1. Remove snap-on cover
2. Unscrew spring retaining bolt at end of shaft.
Remove retainer, spring, and clutch cone. NB Bolt
is assembled with ‘Loctite’ (nutlock)
3. Remove one retaining bolt from guide tube
assembly.
4. Unscrew bolts holding engaging mechanism
housing to body. Remove complete clutch
assembly including pulley and engaging
mechanism from pump.
5. Remove key and shim from shaft.
6. To break down handle, pulley and engaging
mechanism, remove small retaining ring at
bearing, support pulley and press engaging
mechanism sleeves through bearing in handle
and remove handle from engaging mechanism.
7. If pulley bearing needs replacing, remove
retaining ring from pulley and push out bearing.
Disassembly - Pump
1. Remove end cover screws, end cover and gasket.
2. Remove impeller using suitable tool.
3. Loosen cam screw and remove cam.
4. Remove wearplate.
5. Remove bolts holding pump body to bearing
housing and remove pump body.
6. Remove mechanical seal from pump body.
7. Press shaft and bearing assembly out of bearing
housing.
8. Push out shaft from rear bearing supporting the
inner race and remove retaining rings from shaft.
9. Press shaft out of front bearing supporting the
bearing inner race.
10.Remove inner bearing seal.
Assembly - Pump
1. Press new inner bearing seal into housing with lip
facing away from bearing bore.
2. Press shaft into front bearing supporting inner
bearing race. Fit bearing retaining rings on shaft
and push second bearing onto shaft.
3. Grease seal area of shaft. Push bearing and shaft
into body by pressing on outer race of bearing.
4. Position slinger on shaft and replace pump body
and secure with four bolts.
5. Take new seal (cup rubber and seal seat), lightly
grease the outside edge of cup rubber and press
into the cavity in the pump bore with the
ceramic facing the impeller bore.
6. Slide mechanical seal sub assembly over shaft until it
engages against ceramic face of stationary seal. NB
Ensure seal faces are free from dirt and grease.
7. Fit wearplate.
8. Coat cam screw thread and back of cam with non
setting jointing compound and fit into body.
9. Lightly grease impeller bore and push in impeller.
10.Fit gasket, end cover, and end cover screws.
Assembly Clutch
1. Screw engaging mechanism/sleeve into housing
approximately 1 turn. Fit handle over sleeve and set
0.25mm (0.001”) clearance between housing and
handle, when in the off position, by screwing sleeve
in or out as required. Lock handle on sleeve with
grub screws. NB lubricate thread with anti-scuffing
paste.
2. Re-fit bearing and retaining ring into pulley. While
supporting clutch mechanism/sleeve press pulley
bearing assembly onto sleeve hard up against the
handle.
3. Fit pulley/handle/engaging mechanism assembly to
pump with three bolts.
4. Fit guide tube mechanism to handle and to
engaging mechanism housing.
5. Fit shim and key to shaft.
6. Fit clutch cone, spring and spring retainer and secure
with both. Tighten bolt until retainer is clamped
against the shaft. NB Lubricate between shaft and
clutch cone with anti-scuffing paste. Assemble
screws with ‘Loctite’ (nutlock)
7. Re-fit snap on cover.
Clutch Adjustment
When new, the clutch will begin to engage approx.
half-way between the ‘OFF’ and ‘ON’ position. As wear
takes place on engaging position will move towards the
‘ON’ position. When there is little movement left
between the engaging point and the ‘ON’ position the
clutch can be adjusted as follows:
1. When handle is in the ‘OFF’ position remove the
snap on cover.
2. Unscrew spring retaining bolt at end of shaft.
Remove retainer spring, clutch cone and key. NB
Bolt is assembled with ‘Loctite’ (nutlock).
3. Remove shim and re-assemble key, clutch cone,
spring retainer, screw and cover.NB Removal of shim
will restore engagement point to the original
position. Once the shim is removed no further
adjustment is possible and clutch cone and pulley
should be replaced.
Inspect all parts for wear or damage and replace as necessary
