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Writer's pictureRALPH COPE
May 10, 20213 min read

8 FAQs on Excavator Maintenance




Question 1: What is the most common cause of final drive failure? Answer 1: There are numerous causes. One relates to water. If a machine is operating in mud and water, it is possible for water to get past the seal. This will turn the water milky and given that water is not a good lubricant, it creates a less than an optimal condition in which the gears of the final drive are operating. This will lead to a failure in the final drive and the only solution would be to replace the entire final drive. Another reason for final drive failure is not servicing the final drive at regular intervals. This leads to the oil getting thick and drying out which in turn means that the gears are not lubricated.


Question 2: What type of oil should you use in your final drive? Answer 2: This depends on the manufacturer. Most machines come from the factory with mineral oil and it is not uncommon for synthetic oil to be used at the first oil change. In some cases, this can lead to metal filings in the final drive which may require numerous changes of mineral oil to eradicate. You need to do your research – speak to the manufacturer and go online to find what is best for your machine. Question 3: How often should you change the oil in your final drive? Answer 3: Some manufacturers recommend an oil change every 1,000 hours while others recommend every 2,000 hours. There is a compelling argument to overservice your final drives and change the oil every 500 hours. Final drives are exceptionally expensive. New oil is considerably less expensive than a replacement final drive. You do the maths. When you service a final drive, only 90% of the oil comes out. The remaining 10% remains in the final drive and this will contaminate the new oil. If you change the oil every 500 hours, it is highly unlikely that your final drive will fail for a reason linked to oil contamination.


Question 4: Under what conditions should final drives be changed more often? Answer 4: If your excavator is traveling/walking a lot, the wear on the final drive is going to be greater. If your machine is sitting in a scrap yard moving material around without walking long distances, your final drives are going to last longer.


Question 5: When you change the final drive oil, is there anything else that you check for? Answer 5: You want to check the sprocket attached to the final drive. You want to look to see if it is wearing which would be indicated by a sharpening of the teeth. Is it breaking apart, is it chipping, is there compacted dirt that is affecting the working of the sprocket. Question 6: Why does diesel engine oil always turn black right after you have changed it? Answer 6: That is the dirty soot of the diesel that gets past the rings and it’s the unburned carbon that turns black. This is not a bad thing – all diesels do it.


Question 7: Why is it so important that primary and secondary air filters are fastened properly? Answer 7: Air filters need to create a good seal. If any air goes past that air filter without going through it, that is dirty air getting into the engine. This is known as dusting the engine. It starts to sand the rings and the cylinders down. Question 8: Can you put too much oil into the engine? Answer 8: You don’t want to fill up the engine oil too fill. Every dipstick has a minimum and maximum mark – you need to make sure you don’t go above the maximum mark. As the crankshaft spins, it is going to be close to that oil level. If it starts hitting that oil, it starts pushing that oil up into the cylinders. This means that there is too much oil in the cylinders. As the rings come down to wipe the oil off, it can cause a runaway engine. The engine starts to run on the excess oil and accelerated RPM and can cause catastrophic damage to your engine.


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