Maintenance
133
C3M2-OM-EN-02
Note
The majority of bearings used on masts fitted to Combilift trucks are
maintenance free, however a small number of masts utilise bearings that
must be greased every 500 hours. Check the mast bearings for lubrication
passages and grease with EP2 grease if applicable.
Chain Tension Adjustment
The chains on the mast must be adjusted so that each chain acting as one of a pair is
under equal tension to the opposite chain in the pair for proper load distribution and
mast operation.
Checking and Setting the Chain Tension
1. With the mast unloaded raise the sections to put the chains under tension.
2. Press the centre of a strand of chain with a suitable rod and then press at the
same place on the opposite chain of the pair.
3. Each chain in a pair should have equal “give”.
4. If the tension is not equal, tighten the bolt on the anchor of the slack chain.
5. Test the tension again. Adjust until the tension is equal.
6.16.4 Mast Bearings
The bearings on the mast do not require periodic greasing. Check the mast bearings
for cracks or flat areas on the surface and also check for restrictions to rolling.
Replace if any of these are detected and try to eliminate the cause(s) of the failure.
Principle Causes of Bearing Failure
Insufficient Lubrication
The rollers stop rolling and the external surfaces rub on the adjacent
mast channel and start to wear causing flats on the surface.
Shocks
Violent frontal collisions during loading can cause bearings to fail.
The external surface will show cracks that cut the surface parallel to the
rolling axis.
Large Load Centre
Another possible cause of breakage is the mounting of special equipment
to handle loads with a very large load centre e.g. carpets, even if their
weight is lower than the rated capacity.
This condition creates oscillations that cause the detachment of the
external hardened surface of the bearing. In this case circumferential
cracks will appear and will run completely around the roller.
Caution
Never place hands inside the mast to check chain tension.
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