When should a breaker front head be replaced?
The front head carries the tool and the bushings and holds the retainer key. Wear and cracks that new bushings do not cure show that the head is due for replacement.
The bushing seat is worn
Bushings sit tight in their seats in the front head. A worn or oval seat lets even a new bushing move or turn; the tool works at an angle and the new bushing soon fails. If the seat is past the limit in the breaker’s manual, replace the head.
The key holes are oval
The retainer key passes through holes in the front head. Oval holes let the key move, take shock loads and break often. If a new key is still loose, the problem is in the head.
The head is cracked
Cracks mostly start around the key holes, the tie-rod holes and the corners. A crack grows under impact and the head can break in work. Do not keep working with a cracked head; have it checked by a specialist.
To make the head last
Replace bushings and tools in time; working with worn bushings passes the load straight to the head. Grease regularly, avoid blank firing, never pry with the tool and keep the tie-rod nuts tightened as the manual says.
When you choose a front head
A front head is made for one breaker model; its bushing seats, key holes and tie-rod holes must fit that model. Search your breaker’s make and model on the front head page; for some models the head is also offered with the bushings fitted.