McConnel SR460 - PTO Shaft; PTO Setup & Adjustment (First Use); Bottoming out Test

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3.3 PTO Shaft
3.3.1 PTO Setup & Adjustment (first use)
Equipment Required
 Tape Measure
 Marker Pen
The PTO of your machine will be delivered as it left the manufacturer, so will
require to be shortened to give the correct effective length between the machine
and the power take-off of the tractor.
In order to determine the correct length of the finished driveline, hook the
machine to the tractor and proceed to install the two uncoupled/unprotected
semi-shafts to their respective tractor/machine PTO’s. For guidance on fitting
input shafts; see Section 4.5.1.
Place the tractor/machine in the position so the two halves of the shafts are at
the minimum distance between the two ends; see Figure 3.5. At this point,
verify any interference of the outer tube with the yoke inner tube and establish
how much the outer tube needs to be shortened.
On trailed machines, the minimum distance “Dmin” (see Figure 3.5), occurs
between the joints during steering. Verify that in the condition of maximum
extension “Dmax”, which generally occurs when the machine is aligned going
sleeply downslope, the coupling between the two tubes is still sufficient.
The input shaft should be shortened to ensure:
 At least 25mm (1”) clearance at the shortest point (Dmin) between the
end of the shaft and the universal joint
 At least 1/3 of the shafts length overlap engagement at the longest
point (Dmax) between the two CV tube halves
Figure 3.5 – Max/min Input Shaft Overlap
Check and ensure that the shaft has been sufficiently maintained and prepared before proceeding to use using
the machine following the guidance given in Section 5.2.2.
3.3.2 Bottoming Out Test
Equipment Required
 Coloured tape
 Tape measure

Marker p
en or
p
lastic
s
criber
It is important to test whether the shaft has been sufficiently shortened to protect against “bottoming out” by:
3.3.2.1 Disconnecting the input PTO shaft and fully compress the two halves of the shaft together
3.3.2.2 Placing a piece of coloured tape on the inner shield 5mm (3/16”) away from the end of the outer shield
3.3.2.3 Reattach the PTO shaft between the tractor and machine
3.3.2.4 Slowly drive the tractor without the PTO shaft engaged and make the machine turn the tightest turn
possible and follow the most severe terrain expected
3.3.2.5 If at any point the outer shield end becomes any closer than 50mm (2”) away from the placed tape, then
shorten the PTO shaft and then test again
To effectively shorten and modify the input shaft; see Section 3.3.4.