If the hydraulic final drive motor on your vehicle is not functioning properly, it can be a frustrating and costly problem to deal with. Fortunately, there are steps you can take to diagnose and repair the issue yourself, potentially saving you the cost of a professional repair. Here is a step-by-step guide on how to repair a hydraulic final drive motor:
Gather the necessary tools and equipment: Before you begin, you will need to gather all of the tools and equipment you will need to complete the repair. This may include a hydraulic jack, a torque wrench, a variety of sockets and wrenches, a hammer, a punch, a pry bar, and a hydraulic pump. You may also need a replacement hydraulic final drive motor, depending on the severity of the issue.
Raise and secure the vehicle: In order to access the final drive motor, you will need to raise the vehicle off the ground and secure it in place. Use a hydraulic jack to lift the vehicle and place it on stands or blocks. Be sure to engage the parking brake and chock the wheels to prevent the vehicle from moving.
Inspect the final drive motor: Once the vehicle is secure, you will need to inspect the final drive motor to determine the cause of the issue. Look for visible signs of damage, such as leaks, cracks, or broken components. You may also need to use a hydraulic pressure gauge to test the pressure of the motor and determine if it is functioning correctly.
Replace any damaged components: If you find any damaged components during your inspection, you will need to replace them. This may include the hydraulic pump, hoses, lines, or seals. Be sure to follow the instructions provided by the manufacturer when replacing these components, and make sure that they are properly installed and connected.
Test the repaired motor: Once you have replaced any damaged components, you will need to test the repaired final drive motor to make sure that it is functioning properly. Start the vehicle and test the movement of the final drive motor to ensure that it is working as it should.
Reassemble the vehicle: If the repaired final drive motor is working properly, you can reassemble the vehicle. Replace any covers or panels that you removed during the repair process, and be sure to tighten all bolts and fittings securely.
By following these steps, you should be able to repair the hydraulic final drive motor on your vehicle. However, if you are unsure of your ability to complete this repair or if you encounter any problems, it is always best to consult a professional mechanic for assistance.
The sequence for pulling a final drive is broadly the same on every tracked machine, and we set it out in the excavator final drive removal and replacement guide. What changes between machines is the part that catches people out: how the drive is mounted, how much it weighs, what has to come off first and which variant your serial number takes. Here is what differs across the machine types we supply most often, and what each one means for a final drive motor replacement.
A dozer final drive is a different job from an excavator one. The drive is a bolt-on module carrying the sprocket segments at the rear of the track frame, and on a D51 class machine the sprocket segments are usually unbolted before the drive itself, which reduces both the weight and the awkwardness of the lift. Expect the assembly to be heavier than the equivalent excavator unit and plan the lift accordingly.
Two points are specific to dozers. The track must be fully released and, on machines with sealed and lubricated track, the adjuster grease fitting has to be cracked carefully rather than opened fast. And the final drive housing on a dozer often shares oil with the sprocket hub bearing, so check the manual for the correct fill point and quantity before you refit. Getting the oil level wrong here is a common cause of a repeat failure.
On PC-series excavators the drive comes out through the outside of the track frame once the hoses are marked, capped and released. Komatsu changed travel motor specifications several times within the same model designation, so the machine serial number decides which drive you need far more reliably than the model badge does. Our Komatsu final drive motors catalogue holds 441 part numbers for exactly this reason, and the casting number on the old motor is the fastest way to land on the right one.
Compact machines look easier and often are not. The drive is lighter, but access is tight, the hoses are short, and there is rarely room to withdraw the unit without removing the track guard first. On a machine of this size it is worth dropping the track completely rather than trying to work around it.
Mini excavators also carry a small gear oil volume in a housing that runs hot, which is why they are unforgiving about maintenance intervals. Parts for these machines are listed under New Holland final drive motors.
Skid steers and CTLs load the travel circuit far harder than an excavator does, because steering is done by driving one track against the other. Drives come off from the outside with the machine safely supported, and both sides are often replaced together since they have done identical work. Caterpillar owners should start from our CAT skid steer final drive motors page, where the range is broken down machine by machine.
Lifting equipment rated for the assembly, not improvised. Caps and plugs for every hose and port you will open, ready before the first connection comes apart. Labels or tape for the lines. The correct gear oil and the fill quantity from the manual. New mounting hardware if the old bolts have been on and off before, because stretched bolts do not hold torque. And the manufacturer's procedure for your specific machine, which overrides anything general you read online, including this page.
Three of them account for most repeat failures. Hoses reconnected in the wrong order, which sends pressure where the case drain should be and destroys the new motor on the first movement. Track tension set by eye and left too tight, which loads the new bearing from the first hour. And skipping the flush after a failure that put metal into the circuit, which feeds the debris from the old drive straight into the new one. None of the three is expensive to avoid and all three are expensive to repeat.
Confirm the drive is actually the fault, using the symptoms of a failing final drive, and check the economics in rebuild or replace a final drive motor. When you are ready, the full range for nearly 40 brands is in the final drive motors catalogue, new units, shipped across the contiguous United States and Canada, most dispatched the same day.
Hydraulic final drive motors are a key component in the drivetrain of many vehicles, providing the rotational power needed to drive the wheels. However, like any mechanical device, these motors can sometimes fail due to a variety of causes. Here are some common reasons why hydraulic final drive motors may fail:
By understanding these common causes of failure, vehicle owners and operators can take steps to prevent or mitigate the risk of hydraulic final drive motor failure. This may include proper maintenance, such as regularly checking and changing the hydraulic fluid and ensuring that the motor is properly lubricated, as well as avoiding operating the motor outside of its recommended temperature range.
