Brown Products TrenchMaster (F-704 & F-904) - Manual (Page 9)

OPERATING INSTRUCTIONS (CONTINUED)
NOTE: Use the smallest rotor possible when trenching in hard clay, rocky or other difficult soils.
Most cable TV or satellite dealers use a 4” or 5” deep rotor instead of the 7”. By using a smaller
rotor you may trench faster, you have less dirt to clean up and the rotors will last longer.
f. As a safety consideration, where the soil has a large content of gravel and small
rocks, it may be necessary to dig a hole by shovel to start the trench. This may
preclude property damage or an injury from flying debris. (This would apply when
near buildings or populated areas).
g. If you encounter an unusual vibration when trenching, stop and shut off the engine
immediately. Inspect to make sure that a point has not been broken. If a point is
missing or broken, replace the point if it is a rock rotor or replace the rotor if it is a
clay rotor.
h. When installing points on rock rotors, the points must be loose and free to rotate to
prevent uneven wear and breakage. The flat nut must go on first. When the flat
retaining nut is tightened to the end of the threads there should be a gap of 1/16” to
3/32” (thickness of a nickel) between the socket and the flat nut. Use two wrenches
to jam the lock nut against the flat retaining nut. See diagram below.
i. The diagram below provides guidance for positioning components when replacing spindle,
bearings or pulley on all models.
j. Bearing and/or Spindle replacement - To replace the spindle and bearings it is advisable to
remove the clay hood. Before loosening the lock collars you must remove the rotor
pulley.The pulley is cast iron and is easily broken if impacted on the outer edges.Use a
hammer and punch (or 3/4” bolt) against the thick center portion of the pulley. Soaking with
penetrating oil will help. When the pulley is removed, loosen the set screws on the lock
collars. Drive the shaft out from the pulley side. The back-up nut on the spindle is fixed and
should not be loosened. Each bearing seats against a shoulder in the housing. They must
be removed by placing a punch through the housing from the opposite side.
3-3
Rock & Clay
Rotor
Hardened straight nut
Short lock nut
3/32” - 1/16”
1/2" to 1" From edge of bearing housing to edge of rotor
pulley (Line up with Idler and Engine Pulley)
From outside edge of back-up
nut to edge of bearing housing
From outside edge of back-up
nut to edge of bearing housing
1-5/8”
Bearing Housing
Rotor Pulley