Tweet
So what are the faults commonly associated with the final drive? In our many years of repairing plant and construction machinery we have found that some users are too hasty in blaming a machine fault on the final drive, on one occasion we had a customer who replaced a whole final drive unit believing it to be faulty, when changed the problem with the machine was still occurring – on closer inspection the customer found that the problem had been caused by a stone lodged under the pedal, once the stone was removed his problem was solved, but unfortunately he was left with a huge unnecessary dent in his wallet! We’ve provided you with a few bullet points to check when you suspect you may have a problem with your final drive:
One of the main faults we find is that the customer is not changing the oil in the final drive often enough – as a guide, you should be ensuring the oil is changed every 1000 hours.
If the final drive is down on speed/power this could be caused by a problem in the turning joint.
In a mini digger, generally the controls for the valve block are rod operated, check for wear in the pins and linkage as spool travel may be limited.
In machines over 12 tonnes, a common fault is a build up of mud and stones under the travel pedal, this can make the machine “crab off” (not track in a straight line).
Over pumped tracks (too tight) can overload the final drive – if your tracks are too tight you may also shorten the life of your idlers, pin and bushes, sprockets and rollers.
Check over the machine pressures – if the pressures are down it could be a fault in the motor or secondary valves. To determine if it’s the motor it is sometimes possible to do a leak test on the return line.
If the final drive (gearbox side) is full of hydraulic oil then this can indicate that either the motor is faulty or the shaft seal has gone – if the motor is good and the seal has blown, it’s a good idea to check there isn't a blockage in the casing drain line - if the machine is working in bad conditions a build up of clay and muck underneath the machine can crease the pipes and pressurise the casing.
One of the main faults we find is that the customer is not changing the oil in the final drive often enough – as a guide, you should be ensuring the oil is changed every 1000 hours.
If the final drive is down on speed/power this could be caused by a problem in the turning joint.
In a mini digger, generally the controls for the valve block are rod operated, check for wear in the pins and linkage as spool travel may be limited.
In machines over 12 tonnes, a common fault is a build up of mud and stones under the travel pedal, this can make the machine “crab off” (not track in a straight line).
Over pumped tracks (too tight) can overload the final drive – if your tracks are too tight you may also shorten the life of your idlers, pin and bushes, sprockets and rollers.
Check over the machine pressures – if the pressures are down it could be a fault in the motor or secondary valves. To determine if it’s the motor it is sometimes possible to do a leak test on the return line.
If the final drive (gearbox side) is full of hydraulic oil then this can indicate that either the motor is faulty or the shaft seal has gone – if the motor is good and the seal has blown, it’s a good idea to check there isn't a blockage in the casing drain line - if the machine is working in bad conditions a build up of clay and muck underneath the machine can crease the pipes and pressurise the casing.