Grease also needs to be able to withstand heat and pressure. “Breakers exert a tremendous amount of force on the tool,” says Becker. “The material causes heat and pressure in the tool bushing area. So a chisel paste must be used that can handle high temperature and pressure. A chisel paste with a high-temp moly base that has graphite and copper additives is the best for this application.”
Manufacturers typically recommend high-moly grease with a working temperature above 500° F. “The moly provides the added lubrication once the oil additives break down,” says Clinton.
Greg Smith, Allied Construction Products, adds, “If you apply a grease that breaks down at temperatures below 500° F, you have no lubrication once the unit has been run for a while.”
Also pay close attention to the greasing interval, which can vary by breaker and application. “Breakers should be greased at startup and after every two to three hours of operation,” says Jeff Crane, president/CEO, Furukawa Rock Drill USA.
There are visual signs that a hammer is not getting enough lubrication. “As a general rule, if the breaker is hanging in the air and you notice the tool and lower bushing area are dry or shiny, the tool needs lubrication,” says Becker.
Auto lube systems are capable of providing a steady supply of grease to the hammer. “An auto lube pump or lubrication system is a good investment,” says Becker. “This increases the chances that the tool and bushings will get lubricated on a regular schedule.”
The larger the breaker, the more likely you should use an auto lube system. On some larger hammers, you simply cannot supply enough grease by hand. “The breaker needs to be running grease all of the time,” says Crane.
Tramac recommends the use of auto lube systems on breakers 3,000 ft.-lbs. and larger. “We recommend an auto lube system, which will provide a 7mm shot of grease each time the hammer is in operation,” Becker states. “On smaller units, you hand grease. We recommend anywhere from six to 10 pumps of grease every hour and a half to two hours to maintain the proper greasing level.”
Of course, auto lube systems still require attention. “A major concern with auto lube systems can be a false sense of security. It’s not uncommon for the canister or cartridge to empty during operation,” says Crane.
Clinton agrees, noting, “An auto lube system is only as good as the people operating the system and their willingness to fill up that grease station.”
The key is to make sure sufficient grease is applied to the tool/bearing interface. “How often you grease or if you have an auto lube system really makes no difference as long as you monitor the tool and have a sufficient 4 to 6 in. of melted grease flowing from the hammer, properly lubing, cooling and flushing contaminants,” says Smith. “Intervals can vary anywhere from 30 minutes to four hours, depending upon application.”
Inspect for wear
In addition to greasing, routine inspection can save a lot of damage and repair expense. “By not inspecting the breaker properly, it can cost half the value of the breaker in repairs in a matter of weeks,” says Clinton.
A number of breakers are gas/hydraulic operated. “These designs use nitrogen gas in the backhead as a cushion and/or for increased power, and may also utilize an accumulator to absorb hydraulic spikes during operation,” Crane explains. “These gas charges should be checked for the appropriate pressure reading on a weekly basis, as a change in ambient temperature can affect the required pressure.”
Visually inspect for loose or broken bolts and worn out bushings. Keep an eye on tool and bushing wear. “If the tool appears loose in the bushings, the play should be measured and recorded,” says Becker.
“Worn out front bushings will cause misalignment between the piston and working steel. This may allow the piston to contact the inside cylinder wall during operation, thereby damaging the piston and cylinder — the two most expensive components of the breaker,” says Crane.
Tool retaining pins are also subject to wear. “The tool and tool retaining pins should be removed and inspected every 40 hours of operation,” says Smith. “This interval could be longer or shorter depending on material and application. Look for damage in the retaining pin area, as well as determine whether the tool is receiving sufficient grease.”