GMT 050 - 9 Troubleshooting Guide; General; Checklist; Common Malfunctions

GMT 050 User manual
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9. Troubleshooting guide
9.1 General
In manufacturing the GMT 050 felling grapple, care has been taken to tailor the features of the chosen
materials and components in such a way that they perform well in practice. This has been done to
ensure the least possible number of malfunctions.
However, if you encounter unexpected malfunctions, please refer to the troubleshooting guide.
In order to prevent hydraulic malfunctions, it is of crucial importance that the hydraulic system is kept
clean. Cleanliness of the hydraulic fluid and timely replacement of hydraulic hoses will contribute to
error-free performance.
9.2 Checklist
1. Become familiar with the system.
 Take note of service intervals and other instructions.
2. Questions for the operator.
 What went wrong?
 What functions may be affected?
 Is this the right carrying vehicle?
 Has maintenance been done correctly?
 Have valve block settings been changed?
 Have parts been replaced or removed?
3. Operate the machine and the felling grapple.
 Try to trace possible errors/malfunctions.
 Check whether the carrying vehicle actually meets the required specifications.
 Operate at/work with different speeds in order to trace the potential problem.
4. Inspect the machine as a whole.
 First check the hydraulic reservoir.
 Then check the felling grapple. Start with the valve block, hoses for grapple open and grapple
close and the drain line valve.
 Check pressures by measuring them.
 Check all three cylinders (for leaks around couplings or seals).
9.3 Common malfunctions
9.3.1 Sawing problems
Always make another attempt at sawing after fitting a new saw blade and chain. If this does not
solve the problem, please refer to the following potential causes and solutions;
Saw blade does not extend or barely extends from the saw casing:
 Is the piston rod bent?
 Is the blue regulator valve used for saw blade and chain exchange still closed?