8999070: v3 03/09/2018
Page 5.2 of 5.2 pages
Original instructions (ENGLISH)
Website: www.spearheadmachinery.com
5.2
Shear bolt protection
The P.T.O. shaft is fitted with a shear bolt overload protection to prevent damage to the machine if an obstacle is
encountered during operation.
Figure 5.3
The shear bolt is located at the machine end of the P.T.O. shaft. The following procedure should be followed when
replacing or inspecting the shear bolt.
Disengage the P.T.O.
Raise the machine on the lift arms and move to an area with a firm, level surface.
Lower the machine and stop the tractor.
Apply the parking brake, and remove the starter key.
Release the guard restraining chains and disconnect the P.T.O. shaft from the tractor end first, and then from
the machine. This will give access to the shear bolt for inspection and replacement.
Inspect the machine, shaft and ground for possible causes of failure. Check that the blade rotates freely and
does not foul on the body.
Remove any bolt remains from the universal joint, and replace the shear bolt with the correct grade of new
bolt (four spare shear bolts and nuts are fitted to the top of the A-frame). Ensure the bolt is correctly
tightened; see ‘Torque Settings’, Section 6.14.
CAUTION!
Only use the size and grade of shear bolt as supplied by Spearhead Machinery. For further
information refer to Section 8.
Connect the shaft to the machine and then the tractor and attach the guard restraining chains.
Re-start the machine as described in Section 4.3, and check that it operates correctly.
