Disassembly and assembly
Disassembly of the drive unit, i.e. the complete planetary gear with hydraulic motor seems to be rather unproblematic; however we have included here several tips that should help you with this operation. Regardless of the suggestions provided, always follow the original procedures.
To disassemble the final drive, first dismount the rubber track, or detach the track chain. Then, loosen the screws at the sprocket side (allowing you to avoid unnecessary complications at the later stage). After that, disassemble the frame guard at the hydraulic motor side. A good practice at this point is to mark hydraulic hoses with a marking of your choice to prevent further problems with identifying them. Then, disconnect hydraulic hoses and secure them, as well as the hydraulic motor from oil leakage, and from penetration of dirt into the hydraulic system. The next step is to unscrew the screws fixing the final drive to the excavator frame, and removing the complete unit. Note that complete final drive, contrary to what it may appear, are very heavy, and thus require certain safety measures.
Assembly of the planetary gear along with the hydraulic motor - particularly an aftermarket one - may often cause certain problems which we have described below.
Before assembling a complete final drive into a tracked machine, it is recommended to fill the system with an abundance of clean hydraulic oil in order to ensure that the engine is properly lubricated. The drive may be installed afterwards. The first step is to mount the drive unit to the excavator frame. Note that complete final drive fit into the vehicle only in a specific position, which is dependent on the location of holes of the machine frame. When mounting the drive unit to the excavator frame, do not forget about cleaning the adjacent surfaces between the frame and the drive, and about tightening the screws up to specific torque and use a thread lubricant. Maximum screw tightening torque for installing a final drive is always specified by manufacturers in original service manuals for the machines. After screwing in the drive to the machine, proceed to plug the hydraulic hoses. It is likely that, when installing an aftermarket spare, the location of individual connections will be different than on the genuine part. Some threads in the adapters may also be different, so make sure you are well-prepared to this assembly step. It is very important to plug the hydraulic hoses correctly. This has been discussed in a separate chapter, which we recommend you to read. Here we will only mention that incorrect or incomplete connection of a hydraulic motor will cause its damage.
After connecting a hydraulic motor correctly, perform a preliminary test on the newly installed drive. Make sure that the test is performed at low speed, and that the machine is first driven forwards, and then backwards. At this point you can check if the drive is actually moving in the right direction. It is also worth to inspect oil level in the drive gears in case you are not sure if it is sufficient. After that, mount the sprocket, also using appropriate torque and glue, and then install the rubber track, or attach and pretension the chain. Then, test operation of the drive again without load, i.e. on a raised track. Once done, you may begin your normal usage of the machine.