Short answer
When a breaker leaks oil, the usual response is a new seal. But the seal is often the symptom, not the cause: once the bushing wears, the tool no longer runs on centre, the seal takes an uneven load and the new seal fails within weeks. A lasting fix means measuring tool play first, and replacing bushing AND seal together if the limit has been passed.
What the bushing does, and what happens when it wears
The bushing is where the tool is held inside the breaker body. The front head bushing keeps the tool on centre; the thrust bushing limits its axial movement. While both are sound, the tool sits exactly on the piston axis and takes the blow along that axis.
As the bushing wears, lateral play grows. The tool no longer sits on centre and shifts slightly sideways with every blow. The point where the piston strikes the tool moves off centre, and part of the impact energy goes off-axis — into the breaker body itself.
How the chain works
- The bushing wears → lateral play of the tool increases.
- The tool runs off centre → the seal now works against a wobbling surface instead of a true one.
- The seal wears on one side and leaks → "the breaker is leaking", so the seal is replaced.
- The bushing is still worn, so the new seal sees the same uneven load → it leaks again within a short time.
- Meanwhile the off-axis blow also loads the piston nose, the front head and the tie rods.
A familiar picture on site
If the same breaker is on its second or third seal kit within three months, the problem is not seal quality — it is almost certainly the bushing. The seal is the part that pays the bill for a worn bushing.
How to spot bushing wear
The most practical method is checking tool play. With the breaker hanging on the carrier and the tool free, move the tool sideways by hand. A sound breaker has a perceptible amount of play, but the tool does not wobble. Obvious wobble means the bushing is past its limit.
The second sign is the tool itself. If a removed tool shows a one-sided, polished wear mark on its shank, it has not been running on centre inside the bushing. That mark is usually the clearest evidence that the bushing is finished.
The third sign is sound and feel. A breaker working off-axis has an irregular impact sound, and an extra vibration can be felt through the machine.
Why we do not give the figure
Acceptable play and the wear limit in millimetres differ for every model, varying with breaker size and bushing type. Applying another brand’s limit to your breaker leads to the wrong decision. Look the limit up in your manual, or send us your model code.
The right order of work
- Measure tool play first; do not simply ask whether it leaks.
- If play is within the limit, a seal kit is enough.
- If play is beyond the limit, replace bushing and seal together. Fitting only the seal means spending the money twice.
- When changing the bushing, check the tool as well; a one-sidedly worn tool will eat the new bushing quickly too.
- After the job, watch for leaks over the first hours of work and re-check tie rod torque.
What shortens bushing life
Lack of lubrication comes first. Grease carries away friction and dust between tool and bushing; an under-greased bushing lasts a fraction of its normal life. That is exactly why automatic lubrication systems exist.
Second is using the breaker as a lever. Lifting material, rolling stone or leaning the machine on the breaker forces the tool sideways and eats the bushing directly.
Third is a dirty environment. Dust and sand mix into the grease and turn it abrasive. Tools with dust channels and regular greasing reduce this.