Totallyplant
Member
- Joined
- Jan 10, 2013
- Messages
- 10
- Location
- United Kingdom
- Occupation
- Managing Director of Totallyplant.com
Common problems associated with final drives are extensive, but there are some common faults which regularly occur, having some knowledge of these faults could help you to pinpoint a problem quickly and hopefully save you money on what can be a very expensive problem.
Firstly, what is a final drive? A final drive is a reduction gearbox driven by a hydraulic motor. The hydraulic motor drives the final drive through a series of reduction gears. On most machines the speed is determined by the angle of the swash plate in the motor which give more or less flow depending on what mode the machine is in. If the machine is in high speed you will not get as much power as you would if the machine was running a lower speed.
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 in the final drive often enough – as a guide, you should be ensuring this 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 is 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.
These are just a few problems that are commonly experienced by our Engineers at Totallyplant.com which may help you to determine the problem with your machine. It’s is always advisable that you only carry out mechanical or technical work on your machinery if you are experienced, otherwise you should always consult a fully qualified plant engineer or refer to the machine manufacturers recommendations where available.
Firstly, what is a final drive? A final drive is a reduction gearbox driven by a hydraulic motor. The hydraulic motor drives the final drive through a series of reduction gears. On most machines the speed is determined by the angle of the swash plate in the motor which give more or less flow depending on what mode the machine is in. If the machine is in high speed you will not get as much power as you would if the machine was running a lower speed.
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 in the final drive often enough – as a guide, you should be ensuring this 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 is 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.
These are just a few problems that are commonly experienced by our Engineers at Totallyplant.com which may help you to determine the problem with your machine. It’s is always advisable that you only carry out mechanical or technical work on your machinery if you are experienced, otherwise you should always consult a fully qualified plant engineer or refer to the machine manufacturers recommendations where available.
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