Also known as a final drive, this component is what turns the tracks on an excavator. In the image you’re seeing, there are four hydraulic lines connected to it, each with a specific function.
It might look like a messy tangle of hoses, but there’s a clear logic behind it.
Let’s walk through each one.
The Two Big Hoses at the Center
These are your A and B ports. They handle pressure and return. They’re directly responsible for the forward and reverse motion of the machine.
One pushes high-pressure oil into the motor to rotate it in one direction (forward). The other returns the oil. Reverse the flow, and the track moves in the opposite direction. These lines carry all the force.
On larger excavators, you’ll often see them in a split flange configuration, like in the photo, built to handle high pressure and vibration without budging.
Recommended hoses:
- H600 for large machines — rated up to 6100 psi
- H280 for compact and mid-size machines — flexible and field-proven
The Smaller Hose at the Top
That’s the case drain line. It doesn’t move anything, but it plays a critical role in keeping the motor healthy. It quietly drains internal leakage from inside the piston housing back to the tank, preventing pressure from building up inside the motor body.
It’s not a flashy part of the system, but without it, you risk blowing seals or worse.
The Smallest Hose Looping Around
This is your two-speed pilot line. It controls the motor’s speed setting:
- Low speed / high torque – for power-intensive work like climbing slopes or pushing through mud.
- High speed / low torque – for faster travel across flat ground.
Why This Matters for Sales Reps
Understanding the basics of these hose connections builds your confidence in hydraulic conversations, and your customers feel that.
And when things do get technical? We’ve got your back. You focus on the relationship—we’ll help with the rest.
