How to Remove an Excavator Final Drive
A Step-by-Step Guide Before Installing Your New ProSung Final Drive
Replacing an excavator final drive starts with safely removing the existing unit from the machine.
Although the exact procedure varies between manufacturers and machine models, most excavator final drives follow a similar removal process.
This guide explains the general procedure for removing your old final drive, including removing the track, identifying the hydraulic hoses, disconnecting the hydraulic system and safely removing the drive from the track frame.
Important: Always refer to the machine manufacturer's workshop or service manual where available. Final drives can be extremely heavy and hydraulic systems can remain pressurised after the machine has been switched off. If you are not confident carrying out the work safely, use a suitably qualified engineer
Before You Start
Before removing the final drive, make sure you have a clean and safe working area.
You will normally require:
Never rely solely on the machine's hydraulic system to support the excavator while working underneath or around the undercarriage.
Park the excavator on a firm, stable and level surface.
Lower the attachment to the ground, switch the engine off and remove the ignition key.
The machine must be safely secured before beginning work.
Follow the manufacturer's procedure for releasing residual hydraulic pressure before disconnecting any hydraulic components.
Hydraulic oil can remain under pressure even when the engine is switched off.
Never disconnect a hydraulic hose that may still be pressurised.
Before opening the hydraulic system, clean the area around the travel motor and hydraulic connections.
Excavators naturally operate in environments containing soil, sand, dust and other debris. You do not want this contamination entering the hydraulic system when the hoses are removed.
Pay particular attention to the area around:
Keeping the hydraulic system clean is extremely important when preparing the machine for a replacement final drive.
If the sprocket needs to be transferred from the old final drive to the new ProSung unit, we recommend loosening the sprocket bolts while the old final drive is still securely mounted to the machine.
Do not necessarily remove the sprocket at this stage.
Simply breaking the bolts loose while the drive is securely held can make the job significantly easier later.
Trying to loosen heavily torqued or corroded sprocket bolts once the final drive has been removed can be much more difficult.
The track needs to be moved away from the drive sprocket before the final drive can be removed.
Follow the machine manufacturer's procedure for releasing track tension.
On many excavators this involves carefully releasing pressure from the track adjuster grease system, allowing the front idler to retract.
Warning: Track tensioning systems can contain grease under extremely high pressure. Never completely remove a grease fitting or valve unless specifically instructed by the machine manufacturer.
Once sufficient tension has been released, the track can be moved away from the sprocket.
Depending on the machine, it may be necessary to completely separate or remove the track.
With the track tension released, carefully remove the track from around the drive sprocket.
The procedure will vary considerably depending on the size and type of machine.
Small rubber-tracked excavators may be relatively straightforward, while larger steel-tracked excavators may require lifting equipment and additional tooling.
Once removed, position the track safely away from the final drive working area.
You should now have clear access to the sprocket and final drive assembly.
Most excavators have an access plate on the inside of the track frame which allows access to the hydraulic connections on the travel motor.
Remove this cover.
You should now be able to see the hydraulic hoses connected to the rear of the final drive/travel motor.
Do not start disconnecting hoses yet.
First, identify every hose.
This is one of the most important parts of the entire process.
Before disconnecting anything, take several clear photographs of the original final drive and every hydraulic connection.
We also strongly recommend physically labelling the hoses.
Coloured cable ties or coloured tape work particularly well.
For example:
Place the corresponding colour or label next to the port on the original drive.
Do not rely on memory.
Your replacement ProSung drive may have a different port arrangement from the original drive, so knowing exactly what each machine hose does is more important than simply remembering its physical position.
Keep these photographs.
If you are unsure about the connections when installing your ProSung final drive, send the photographs to our technical team before connecting the new unit.
This deserves particular attention.
Most piston-type travel motors require a case drain, sometimes referred to as a leak-off line.
A small amount of hydraulic oil naturally passes internally through the rotating components of the hydraulic motor. The case drain allows this oil to return to the hydraulic tank at very low pressure.
The case drain therefore must be connected to the correct port on the replacement motor.
An incorrectly connected, blocked or pressurised case drain can cause pressure to build inside the travel motor and may result in rapid or catastrophic motor failure.
Never assume that the smallest hose is automatically the case drain.
If you cannot positively identify the case drain, stop and contact us before installing the replacement drive.
Once all hoses have been photographed and clearly identified, they can be disconnected.
Have suitable containers available to catch escaping hydraulic oil.
As each hose is removed:
CAP THE HOSE IMMEDIATELY.
Do not leave hydraulic hoses open while you continue working.
Also plug the ports on the old travel motor where possible.
This protects the machine's hydraulic system from:
Even very small amounts of contamination can damage hydraulic components.
Never use dirty rags to plug hydraulic hoses.
Use proper hydraulic caps and plugs wherever possible.
While disconnecting the old final drive, pay attention to the condition of the oil.
Look for:
If the previous final drive suffered a major internal hydraulic failure, contamination may have entered the machine's hydraulic system.
Do not simply connect a new final drive to a contaminated hydraulic system.
If you find significant metal contamination or debris, the cause should be investigated and the hydraulic system may require cleaning or flushing before the replacement drive is installed.
A new final drive cannot correct an underlying hydraulic system problem.
Before removing any mounting bolts, support the final drive with suitable lifting equipment.
Final drives can range from relatively small units to assemblies weighing hundreds of kilograms.
Never assume you can safely support the unit by hand.
Attach an appropriately rated sling or lifting device and take the weight of the final drive.
Apply enough tension to support the assembly without pulling against the mounting bolts.
The final drive must be fully supported before the final mounting bolts are removed.
The final drive is normally secured to the track frame by a series of bolts around the mounting flange.
With the final drive properly supported, loosen and remove these bolts.
Depending on the machine, the bolts may be accessible from inside the track frame.
Keep the mounting hardware organised if it is going to be reused.
Before reuse, inspect the bolts and threads for:
Refer to the machine manufacturer's specifications regarding bolt reuse and replacement.
Once the hydraulic hoses and mounting bolts have been removed, the final drive can be carefully withdrawn from the track frame.
The unit may not immediately come free.
Years of dirt, corrosion and loading can cause the mounting flange to become stuck.
If necessary, carefully work around the mounting flange to release it.
Do not repeatedly strike the hydraulic motor housing with a hammer.
This can damage the motor and may make inspection of the failed unit more difficult.
Maintain control of the final drive using the lifting equipment as it separates from the machine.
Once free, lower the assembly onto a suitable pallet, stand or stable working surface.
If your replacement ProSung final drive does not include a sprocket, the existing sprocket will normally need to be transferred.
If you loosened the sprocket bolts earlier, they should now be considerably easier to remove.
With the old final drive safely supported, remove the sprocket bolts and separate the sprocket from the drive.
Inspect the sprocket before transferring it.
Check for:
A badly worn sprocket can accelerate track wear and should be replaced rather than transferred to the new drive.
Before installing the new ProSung final drive, thoroughly clean the mounting area on the track frame.
Remove:
Pay particular attention to the mounting face.
The new final drive should sit correctly and evenly against the track frame.
Also inspect the hydraulic hoses and fittings while access is available.
Look for damaged hoses, cracked outer coverings, corrosion, leaking fittings or damaged O-rings.
Before Installing Your New ProSung Final Drive
You are now ready to prepare the replacement drive for installation.
Before fitting it, we recommend placing the old drive and new ProSung drive next to each other and comparing them.
Check:
Mounting flange
Confirm the mounting diameter and bolt pattern correspond with the original unit.
Sprocket mounting
Check that the sprocket mounting pattern corresponds with your existing sprocket.
Overall dimensions
Minor visual differences are normal between OEM and replacement drives, but confirm there are no clearance issues.
Hydraulic ports
Identify every port on the ProSung drive before connecting any hydraulic hoses.
Main feed ports
Confirm the two main travel lines.
Case drain
Positively identify the case drain connection.
Two-speed connection
If your machine uses two-speed travel, identify the two-speed pilot connection.
Do not connect hoses purely according to where they were positioned on the old motor. Port locations can differ between motor manufacturers and designs.
STOP — Before You Install the New Drive
If you are unsure about any hydraulic connection, do not guess.
Incorrect hydraulic connections can damage a new travel motor extremely quickly.
Take clear photographs showing:
Send these details to Pro Construction Parts and our team can help you identify the correct connections before installation.
What NOT to Do When Removing a Final Drive
Avoid these common mistakes:
Don't disconnect hoses without labelling them.
You may struggle to identify the correct connections when the new motor arrives.
Don't leave hydraulic hoses open.
Cap them immediately to prevent contamination.
Don't guess which hose is the case drain.
Incorrect case drain connection can destroy a travel motor.
Don't remove mounting bolts before supporting the drive.
The assembly can be extremely heavy.
Don't hammer the travel motor housing to remove it.
Use appropriate removal methods and lifting equipment.
Don't automatically install a new drive after a catastrophic motor failure.
Check the hydraulic system for contamination first.
Don't assume the new drive's ports will be in exactly the same positions.
Identify them by function, not simply by physical location.
Ready to Install Your ProSung Final Drive?
With the old final drive removed and the mounting area cleaned, the next stage is preparing and installing your replacement ProSung drive.
Our installation guide covers:
Next Guide: How to Install a ProSung Final Drive
Need Help Identifying Your Final Drive?
If you haven't ordered your replacement drive yet, Pro Construction Parts can identify the correct ProSung final drive from your machine details.
Send us:
Machine Make
Machine Model
Machine Serial Number
Final Drive Part Number, if known
Photos of the existing drive and hydraulic ports
We supply ProSung final drives for thousands of excavator, mini excavator and tracked machine models worldwide.