A travel motor holds a parked machine with a spring-applied brake that is released by hydraulic pressure when you travel, backed by a counterbalance valve that locks the motor ports. Creep comes from three places: the brake not applying, the counterbalance valve leaking past its seat, or the motor leaking internally. Park on a slope in neutral with the engine off and watch the tracks for ten minutes. Movement with the engine off means the brake or the counterbalance valve is not holding. Movement only with the engine running points at the brake release circuit or at motor leakage. A case drain measurement at operating temperature then separates a worn motor from a valve fault, and the whole sequence takes an hour and no parts.
What you will notice
| Symptom | What it usually points to |
|---|---|
| The machine rolls slowly when parked on a slope with the engine off | The brake is not holding. This is the one pattern that is unambiguous, and it is a safety fault rather than a performance complaint. |
| One track drifts while the other holds | A fault local to that motor: its brake, its counterbalance valve or its internal clearances, rather than anything shared by the travel circuit. |
| Travel is slow to stop after the levers return to neutral | Brake release pressure lingering, or a travel spool that is not returning fully to center. The brake applies late because the release signal stays on. |
| A single clunk or jerk as travel stops | Worn brake plates, a broken brake spring or backlash in the final drive. Noise on application is mechanical; creep without noise is usually hydraulic. |
Most likely causes
| Cause | How to confirm it |
|---|---|
| Brake piston seal failed, so release pressure reaches the brake | The brake is applied by springs and released by pressure. A leaking piston seal lets release pressure past the piston at all times, so the brake drags or never fully applies. |
| Counterbalance valve seat damaged by contamination | The valve is what holds the motor still when the spool is centered. A seat marked by debris lets the motor turn under load even with a healthy brake, which is why the slope test is run twice. |
| Worn rotating group in the travel motor | High case drain means oil is passing internally instead of holding. The brake can be perfect and the machine will still creep downhill as the motor slips. |
| Brake plates worn or a spring broken | Disc stack wear reduces clamping force gradually, so the machine holds on the flat and creeps on a gradient. A broken spring removes the clamp on one side with no warning. |
What the machine does, and what it proves
| Observation | Conclusion and next test |
|---|---|
| Creeps with the engine off, in neutral, on a slope | Brake or counterbalance valve. Measure brake release pressure at the motor port with the control in neutral: any pressure here is the fault. |
| Holds with the engine off, creeps only when running | Release circuit or motor leakage. Case drain flow at operating temperature decides which. |
| Creeps in one direction only | A counterbalance valve seat on that side, since the brake and the motor are shared by both directions. |
| Creeps badly when the oil is hot, holds when cold | Internal leakage. Clearances open as viscosity falls, and the brake itself is temperature-insensitive. |
| Holds on the flat, creeps on a gradient | Reduced clamping force: worn plates or a weakened spring. On many motors the brake can be rebuilt in place. |
How to confirm it
- Park on a firm slope with room to move and chock the machine
Use a slope you can measure, with a clear run-off in case the machine does move. Lower the attachment, release residual pressure and keep everybody clear of the tracks. A creep test on a machine that might roll is a test nobody should stand next to.
- Mark the track and the ground, then time ten minutes with the engine off
Chalk a line across the shoe and a matching line on the ground. Measure the movement after ten minutes and write the number down, because the difference between a healthy machine and a marginal one is centimeters, not meters.
- Repeat with the engine idling and the control in neutral
Pressure is present in the circuit but no travel is commanded. A machine that holds with the engine off and creeps now has a release pressure or leakage problem, not a brake problem.
- Measure brake release pressure at the motor
Tee a gauge into the brake release port. With the control in neutral the reading should fall to zero. Pressure that stays up means a leaking spool or a blocked return, and the brake never gets to apply fully.
- Measure case drain at operating temperature
Route the drain into a measured container for sixty seconds at rated speed in neutral, and compare with the specification as a share of motor flow. This is what separates a worn motor from a valve fault.
- Drain the final drive and inspect the oil
Metal or a silvery sheen means the final drive is contributing. Water or the wrong oil changes the diagnosis, and a brake running in contaminated oil will not hold for long even after a rebuild.
What to do about it
Creep with the engine off and no release pressure: the brake is at fault. Rebuild it with new plates, springs and piston seals, or fit an exchange motor where the brake is not serviceable separately. Check the release port is not holding pressure before the machine goes back to work, or the new brake will be dragged to failure the same way.
Creep only with the engine running and high case drain: the motor is worn internally. A reseal will not close clearances in the rotating group, so the honest repair is an exchange or replacement motor, and the final drive oil should be changed at the same time.
Creep in one direction with correct case drain: the counterbalance valve is the suspect. Strip and inspect the seat and the poppet, replace the valve where the seat is marked, and flush the circuit, because whatever damaged the seat is still in the oil.
Travel motors, brake plate and spring sets, counterbalance valves, seal kits and final drive components are supplied by Guangzhou Shenyue Machinery Technology Co., Ltd. from Guangzhou, with 3,000+ part types on the shelf and 100,000+ part numbers available to order, and every line declared as genuine, OEM-quality or aftermarket. The five brands for which the company holds authorized dealer status are Garrett, Mitsubishi Heavy Industries, TONGMYUNG, NIKURA and Marusan, and the Mitsubishi authorization covers MHI engine parts only. Kobelco is not among them, and Kobelco parts are supplied through original channels or as quality alternatives.
Parts you may need, by grade
| Part | Grades commonly quoted |
|---|---|
| Travel motor | Genuine; OEM-quality new; remanufactured exchange with core return. Confirm the brake type, since some motors use a separate brake valve. |
| Brake plates, springs and piston seals | Genuine; OEM-quality to the same stack thickness. A thinner stack reduces clamping force before it fails. |
| Counterbalance valve | Genuine; OEM-quality with the setting confirmed against the model. A valve set for a different machine holds differently. |
Need the parts this covers?
Send the machine model, serial number and the part numbers you need. We confirm fitment before payment and state the grade of every line — genuine, OEM-quality or aftermarket.
Request a quoteFrequently asked
Can I keep working with a machine that creeps only slightly?
Not on a slope. The brake is the only thing holding a parked machine, and a creep of a few centimeters a minute on a gentle grade becomes a runaway on a ramp. Repair it before the machine goes back on a stockpile or a trailer ramp.
Why does the machine creep when hot but hold when cold?
Oil viscosity. Internal leakage through the motor and the valve rises as the oil thins, and by the time the oil is at operating temperature the leakage is enough to let the motor turn. This pattern points at clearances rather than at the brake.
Do both tracks creep together when the brake is worn?
Usually yes, because both motors see the same hours and the same duty. One track creeping and the other holding points at a fault local to that motor instead, which is a cheaper repair and a different diagnosis.