12 ► MB05 User Manual
Use a “scoring” method of breaking when cracking 
the  material  becomes  difcult. This  technique  involves 
striking the rock or concrete at several places along a 
line where you want the crack to occur. Most materials 
break sooner when struck several places along a line 
than when struck repeatedly in one location. On each 
line, the breaker tool should be continually repositioned. 
Practice determines the best length of time to stay in 
one spot. (15 – 20 seconds) and how far to move the 
breaker tool.
Do not break continuously 
in one place.
15 – 20 seconds. If breakout does not occur within this 
time, move the breaker to another position.
On  at  material  such  as  concrete  runways,  starting  to 
break in the middle of the material may cause vibrations 
to be transmitted throughout the breaker and excavator 
because the material has no place to break to. Always 
try to start at a point which will permit the material to 
break out.
MAINTAIN DOWN PRESSURE
Maintaining hard contact with the surface of the material 
to be broken in addition to maintaining adequate “down 
force” is very important. Always keep “down pressure” 
or “down force” on the point of the breaker by lifting the 
wheels, tracks, or stabilizers slightly above the ground. 
This method takes the “slack” out of the bracket and 
boom pivots, and reduces the impact on the pivots in 
the boom.
The operator needs to be constantly aware of the amount 
of down pressure being applied and be able to adjust it 
if necessary. Not enough down pressure results in low 
production and accelerates wear and tear on the equip-
ment. Too much down pressure may cause the breaker 
housing to violently crash into the broken material when 
“break-through” occurs.
In any breaking job, the operator should make every ef-
fort to “follow” the breaker with “down pressure” as the 
machine breaks farther into the material. The breaker 
should be stopped as soon as “break-through” occurs or 
if it is apparent that good solid blows are not occurring.
BREAKING
The operator should note the sound of the blow when 
the breaker is running. With experience, the operator will 
be able to tell the difference between a good solid blow 
and a hollow sounding blow. A hollow blow means that 
solid blows are not occurring and breaker should be re-
positioned.
Continuous tool penetration usually does not do much 
good. If the material does not break with 3 – 6 inches of 
tool penetration, it usually won’t break with full penetra-
tion. The time used for additional penetration could be 
better used to strike blows in another place.
Many materials do not respond well to continued ham-
mering in one place. The breaker tool should be repo-
sitioned on the work each time the tool penetrates but 
does not crack the material.
Continuous penetration in the same area for lengthy 
periods will create excessive temperatures at the tip 
of the tool bit resulting in loss of temper (hardness) 
of the bit, mushrooming of the tip of the bit and may 
lead to failure of the bit.
OPERATION