Replacement of Worm Gear Bearings
Where to buy Molykote 321-R Bote-Spray 400ml in the Canarias :
SIEMENS MAQUINARIA, S.A.
c/ Los Dragos, P.235
35119-POLIGONO DE ARINAGA
The sales person is : 'Ricardo Guardia' ,
móvil 630978959, in La Palma the telephone number is 922402681.
Address of the La Palma shop is (found on the WWW):
Pedro M. Hernandez Camacho, 10
38760 - Los Llanos Aridane
- Unscrew the bracket holding the D-type connector.
- Remove the four motor screws.
- Loosen the two grub screws attaching the motor shaft to the
- Unscrew the worm gear assembly from the wheel assembly been
careful not to loose the shimes.
- Once the worm gear is free put its screws back into the wheel
assembly with the shimes in their original positions.
- Unscrew and remove the end cover.
- Remove the spring clip which is know visible from the end
of the worm shaft, using the proper spring clip tool, found in the electronics
- Take out the eight spring washers.
- Knock out the pin holding the worm to the shaft. To do this support
the back of the worm on the special tool and from the hole in the gear
housing push a pin out with the pin extractor tool and plastic hammer.
| Removal of worm gear pin. Note
the special tool mounted in the vice
| Removal of worm gear shaft and
- Knock out the shaft from its housing using the plastic hammer.
- Remove the worm gear. Note it comes in two halves with a spring
between and are aligned with each other by the scratch marks.
- Knock out the two bearings from the inside. For the first one use the
short arm of a large Allen key. For the other you can knock it out through
the hole left by the first bearing.
- Once everything is dis-assembled clean with acetone.
| From top left: flexible coupling,
end cover two halves of the worm gear and their spring, pin, worm gear shaft,
spring washers, spring clip and an old bearing
| Fitting the worm gear assembly
to the wheel assembly. A screwdriver is been used to compress the two halves
of the worm gear together
- Push in the new bearings, with the flanges on the outside, and press
them in using the brass tube so you only push on the outer ring of the bearing.
- Put the worm gear in and slide through the shaft. Check the two
halves of the worm gear are correctly aligned by the scratch marks. Don't
forget the spring.
- Align and knock the pin in place.
- Replace the eight spring washers. These washers go in in alternate
faces starting with the first like a saucer then the next an upside down
- Replace the spring clip, using the spring clip tool, ensuring the
clip sits in the slot.
- Replace the end cover.
- Remount the worm gear assembly on to the wheel assembly been careful
not to loose the shimes. It is necessary to compress the two halves of
the worm gear together for them to mesh with the wheel gear. Do this by
pushing up on the flexible joint by levering with a suitable device, such
as a Allen key or screwdriver, on the housing.
- Keep the worm gear assembly pressed against the wheel replace the
four mounting screws. It may require two people to do this.
- Replace the motor, four screws, and tighten both grub screws in the
- Replace the connector and check you can turn the worm wheel by hand,
it should turn with some resistance.