4.0 Operation and Adjustment
4.1 Operating
Before attaching a subsoiler to a tractor is essential that the stands are in the down position to ensure a
short top link once attached. Once attached securely to the tractor the machine can then be raised and the
stands lifted out of the way. When the machine is removed from the tractor is equally as important to
leave the machine on the stands.
Due to the physical nature and weight distribution of the Sumo Subsoiler a category three enclosed ball
top link is highly recommended as the best option for dealing with the exaggerated loads experienced
during normal working conditions.
The top link should be as short as possible whilst remaining as close to horizontal as is achievable. In the
majority of cases this means using the bottom hole on the Subsoiler and the top hole on the tractor. It is
important to ensure the machine is running level to allow the optimum level of soil disturbance as well as
to prolong the life of the wearing parts.
Changing the points on the Subsoiler must only be done on level ground. When it is deemed necessary to
change the points, the stands should be lowered to the static position and other appropriate jacks, stands
and chocks put into position in sensible locations. To avoid the risk of sinking and potential injury it is
important to only change the points where ground conditions permit, i.e. solid concrete, tarmac etc. Care
should be taken to ensure the subsoiler is firmly and safely held before changing the points. The tractor
engine must be turned off with the parking brake applied. In order to change the points it is first necessary
to remove the nut and bolt behind the point freeing the worn part. Then a new point can be replaced in the
same position, with the appropriate nut and bolt tightened up to secure the point in position.
Bearings should be greased (see 5.0 Maintenance), stands must be in the raised position and all relevant
pins in the correct holes prior to commencing work.
Forward working speed should be governed by the local conditions as well as the finish produced by the
Subsoiler.
4.2 Adjustments
Depth adjustment of the subsoiler legs is achieved by altering the height at which the packer is set and a
combination of the top link length and lower linkage height. The machine should always remain level in
when working. The lower packer pin must be placed in the upper-most hole under the packer arm to
prevent the arms chasing and wearing in the slots every time the machine is raised. Failure to do this can
result in excessive wear to the packer arms, main side plates and the quadrants.
4.3 Auto-Reset
The pressure in the hydraulic circuit controlling the auto-reset subsoiler legs can be altered depending on
circumstances and preference up to a maximum of 50 bar. (Exceeding this pressure may result in damage
to the machine). The higher the hydraulic pressure, the more resistance the legs have to tripping.
To increase the pressure, open the flow control valve tap (item 8 on page 17) and then continue to
pressure the spool valve until the desired system pressure is displayed on the pressure gauge. At this point
close off the tap. To reduce pressure in the circuit, slowly open the tap whilst watching the pressure
gauge, once the desired lower pressure is reached, shut off the tap immediately.
