User Guide

The Three Point Hitch
1
Top Link Connection
One end of the top link is fastened to the tractor at
a bracket located behind the tractor seat. The other
end of the top link is connected to the top bracket
of the implement ‘A” frame. Both
connections are secured with a top link pin
(similar to a clevis pin).
Top link pins are always unthreaded and are held in
place by either a linch pin, or in some cases, a large
hairpin clip. (see fig. 3) Top link and top pins vary in
length, but their respective ball socket holes and
pin diameters are standardized by horsepower
category. (see fig. 2)
Lift Arm Connections
Background
Hitching Up Dierent Categories
Most tractors are equiped with a three point hitch
for attaching implements to the tractor. It lets the
operator raise implements when transporting them
and provides height and tilt adjustments during use.
The three point hitch gets its name from the tractor’s
three hook up points: two lower lift arms and one top
link. (see fig. 1) Special pins are used to fasten the
implement at these three points. They are called top
link pins at the top link connection and lift arm pins
at the lift arm connections.
The diameters of the connection pins and corre-
sponding ball sockets of the tractor’s hitch points
have been standardized by the American Society
of Agricultural Engineers (ASAE) by horsepower
category. (see fig. 2)
Leveling Arm Assembly
One end of each lift arm is secured to the tractor
axle housing by a special OEM (original equipment
manufacturer) mounting pin. The other end of the
lift arm is connected to a lift arm pin, that has been
fastened to the lower bracket of the implement’s
‘A’ frame. Category 0, 1 and lighter category 2
implements use threaded lift arm pins that are
bolted to the implement bracket. (see fig. 4)
Heavier category 2 and most category 3
implements use special clevis pins, that are
mounted through two brackets on the implement,
thereby supporting both ends of the pin, similar
to the top link connection. (see fig.3)
Most lift arm pins (other than clevis pin types) are
threaded on the end that bolts to the implement
bracket. The unthreaded end with the cross hole
accommodates teh ball socket of the lift arm. The
lift arm is secured on the pin with a linch pins or
large hair pin clip.
(see fig. 4)
Lift arms and lift arm
pins vary in length,
but their respective
ball socket holes and pin
diameters are standized by
horsepower category.
(see fig. 2)
Sometimes a tractor must be hitched to a dierent
category implement. For example, a new category 2
tractor may be used to mow with an older category 1
rotary cutter. A category 1 top link pin should be
used with a category 1 to 2 bushing to fit the tractor’s
category 2 top link ball socket. Agralink™ oers
special lift arm pins withadierent diameter on each
end. In this case, the category 1 pin could be replaced
with a special lift arm pin, that has a 7/8” diameter
threadedend to fit the category 1, 7/8” hole in the
implement bracket and a category 2, 1-1/8” diameter
unthreaded end to fit the tractor’s category 2 lift arm
ball socket. Agralink makes special pins and bushings
in many varieties.
Fig. 1
Fig. 3
Power Take O (PTO) Top Link
Lift Arm Check Chain
Swinging Drawbar
Drawbar
Stabilizer Arm
Maximum Top Link Lift Arm Lift
Drawbar Pin Pin Arm
Category Horsepower Diameter Diameter Spacing
0 up to 20 5/8” 5/8” 20”
1 up to 45 3/4” 7/ 8 ” 26”
2 40 to 100 1” 1-1/8” 26” or 32”
3 80 to 225 1-1/4” 1-7/16” 38”
Fig. 2
Fig. 4