Section 7. Component Procedures
Model 5200 High-Level Orderpicker
Mast Shimming
Mast Section
Mast Shimming Shimming a mast makes a smooth running unit that is not too tight or too loose. If you find any marks within the telescopics or main frame where the rollers have been running, remove them using a sanding disc and 80 grit paper. Do not attempt to remove all marks, only the ridges. Shim the bearings to the tightest spot on the assembly (as the rollers run up and down the rail). Buff small areas that are slightly higher than the rest of the web to avoid shimming the major portion of the rail too loose. The shims used under each roller bearing come in the following sizes: thin, medium, and thick. Although you can use different combinations of shims to obtain the correct adjustment, you should try to maintain equal shim thickness on each side of the mast.
Mast and Bearing Inspection Observe mast operation in free and main lift with no load. •
When stopping a lift or lower, there should be a slight bounce.
•
If the bounce dampens out quickly, the mast may be shimmed too tight.
Compare the wear pattern on the rail (where the roller rides) to the examples shown in Figure 7-207. •
If the wear pattern is optimal, shimming is adequate.
•
If the wear pattern is excessive, shimming is too tight.
•
If the wear pattern varies between optimal and excessive, the telescopic weldment is suspect.
NOTE: Uneven wear can also indicate which bearing set is too tight. Approx. 1 in. (25.4 mm) wide wear pattern
OPTIMAL WEAR PATTERN Shimming is adequate
Side of rail bearing rides on
Observe the mast operation at full elevated height, just short of hitting the hard stops, with no load. •
The telescopic should all act as one.
•
The interface between the telescopics should be snug with no excessive relative motion between the telescopics when the lift truck is moved back and forth slightly. If motion is excessive, the mast may be shimmed too loose.
•
If a 0.010 in. feeler gauge can be inserted between the roller and beam web at the tightest spot, they are shimmed too loose. Some telescopics can be narrower at the top or bottom, therefore shimming clearance should be measured at the tightest location.
7-108
EXCESSIVE WEAR PATTERN Shimming is too tight
Wear pattern greater than 1 in. (25.4 mm) wide
Example of good wear pattern on mast with several hundred hours
Figure 7-207. Mast Bearing Wear Patterns
Publication Number: 1043922A, Revised: 2 Sept 2015
