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HKM

Breaker Troubleshooting Guide

Breaker Leaking Oil

Where the leak appears tells you most of the cause. Establish the source first: the tool area, the body joint and the fitting area point to completely different causes.

← All symptoms

First checks on site

  1. 1Clean the leak area and look again after a short run. On a dirty surface it is impossible to find the source.
  2. 2Distinguish oil from grease. Grease pushed out of the tool area by over-greasing is often mistaken for an oil leak.
  3. 3Check tool play: if the tool moves excessively sideways the bushing is worn, and that is very likely the real cause of the seal damage.

Causes by leak location

1.Leak at the tool area: seal kit has reached the end of its life

Is this the one?
Oil comes from where the tool enters; tool play is normal and there are no other marks on the body.
How to check
Measure tool play. If play is normal, the cause is most likely the seals alone.
What to do
Renew the seal kit. Have the bushing condition checked at the same time.
Related part →

2.Leak at the tool area: bushing wear (the real cause)

Is this the one?
Oil comes from the tool area AND the tool moves noticeably sideways. If seals were replaced recently and it started leaking again soon after, the diagnosis is clear.
How to check
Check lateral tool play. When the bushing wears, the tool runs off centre and continuously crushes the seal on one side, finishing it quickly.
What to do
Replace the bushing and the seal kit together. With bushing wear, replacing only the seals is a temporary fix that produces a repeating cost.
Related part →

3.Scoring or chrome damage on the piston surface

Is this the one?
The seal leaks again quickly and a regular scoring mark appears on the new seal.
How to check
Inspect the piston surface during disassembly, looking for scoring, heat marks or chrome flaking.
What to do
Have the piston assessed by a service workshop. A damaged surface cuts every new seal; changing seals alone is not a solution.
Related part →

4.Leak at the body joint

Is this the one?
Oil comes from the line where the body sections meet. Usually seen together with tie rod loosening.
How to check
Check tie rod torque and look for cracks in the joint face.
What to do
Apply torque as specified in the manual. If loosening keeps recurring there may be blank firing fatigue behind it.
Related part →

5.Leak on the gas chamber side: diaphragm

Is this the one?
The leak comes with the gas chamber failing to hold pressure. When both appear together the diagnosis is very likely this.
How to check
Assess whether the pressure loss and the leak appeared at the same time.
What to do
Have the diaphragm replaced during service.
Related part →

6.Fitting, coupler or hose connection

Is this the one?
The leak is at a connection point rather than on the body; the breaker itself is dry.
How to check
Clean the connections and check again after a short run.
What to do
Tighten the fitting to the correct torque and renew the O-ring or hose. This is the easiest of all leak causes to resolve and should be eliminated before any unnecessary disassembly.

When to stop

  • Do not close a leak by replacing seals alone without finding the cause; if the bushing is worn the cost will repeat quickly.
  • Do not keep working with a leaking breaker; if the level drops the circuit heats and the damage grows.
  • Do not over-torque fittings to stop a leak; the O-ring is crushed and the leak gets worse.

Frequently asked

I replaced the seals but it still leaks. Why?

In this picture the real cause is usually bushing wear. When the bushing wears, the tool runs off centre and crushes the seal continuously on one side; even the best seal fails quickly. The bushing and seal must be assessed together.

How do I tell whether the fluid at the tool area is oil or grease?

Clean the area and look again after a short run. Grease is darker and stickier and usually collects right around the tool seat. Over-greasing is frequently mistaken for an oil leak and leads to unnecessary disassembly.

What does it mean if the oil leak comes with falling gas pressure?

The two appearing together points to diaphragm damage. In that case neither recharging the gas nor replacing the seals will work; the diaphragm has to be replaced.

Related symptoms

Breaker Blank Firing

Striking into air after the material has broken — the fastest way to wear a breaker out.

Breaker Overheating

Oil temperature climbs and the body becomes too hot to touch.

Send us the symptom and your machine model; our service team will walk through the field steps with you. Brand does not matter — we supply parts and service support for all breaker makes and models.

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