WARNING
Do not overload any tractor axle by improperly
loading the trailer. This could cause erratic steer-
ing and loss of vehicle control, possibly resulting
in serious personal injury or death.
Fifth Wheel Lubrication
For lubrication instructions, see Group 31 of the
Century Class Trucks Maintenance Manual
.
ASF Castloc II and Simplex
Series Fifth Wheels
General Information
The ASF Castloc
®
II and Simplex
®
series fifth wheels
are used for pulling trailers having the standard
2-inch (51-mm) diameter kingpin. When installed as
a stationary fifth wheel (
Fig. 10.8
), they are bracket-
mounted to the tractor frame in a position that best
distributes the trailer load over the tractor axles.
When used as a sliding fifth wheel (
Fig. 10.9
), they
are mounted on the Taperloc
®
sliding mount (air-
operated or manual release).
The fifth wheel lock mechanism for the trailer kingpin
consists of a rotating jaw that grips the trailer kingpin
and a spring-actuated lock. The jaw rotates on a jaw
pin during coupling and uncoupling operations. King-
pin lockup occurs when the kingpin is forced into the
jaw and the operating rod handle moves to the
locked position. The kingpin is released either by ac-
tivating a manual operating rod, or if equipped with
Touchloc
®
, by a dash mounted release-knob, which
activates an air cylinder underneath the top plate.
The air cylinder activates the operating rod. The op-
erating rod is located on the left side of the fifth
wheel for Castloc II and Simplex II fifth wheels, and
on the right side for the Simplex fifth wheel assem-
bly.
On sliding fifth wheels, the top plate is mounted on a
sliding saddle plate, which slides along the baseplate
attached to the tractor frame. The baseplate rails
allow forward and rear movement of the slide assem-
bly, for optimum weight distribution over the tractor
axles.
Tapered slots in the baseplate rails, aligned in 4-inch
(102-mm) increments, provide for location of the fifth
wheel along the baseplate. Retractable, spring-
actuated lockpins are positioned through the slots to
hold the fifth wheel in the desired position. The lock-
pins are retracted either manually or by an air-
operated cylinder controlled from the cab.
The manually-operated slide contains an operating
rod (
Fig. 10.9
) which unlocks both sides of the plate
at the same time.
The air-operated sliding saddle plate contains an air
cylinder which moves the operating lever to unlock
both sides of the plate at the same time. The air cyl-
inder is activated by a two-position air-control valve
in the tractor cab.
f310353b
1
2
3
4
10/26/2010
1.
Lubricant Grooves
2.
Safety Latch
3.
Operating Rod
4.
Mounting Bracket
Fig. 10.8, Simplex Stationary Fifth Wheel
1
2
3
4
5
6
3
10/26/2010
f310445
7
8
1.
Baseplate
2.
Bolted Stop
3.
Baseplate Rail
4.
Fifth Wheel Mount
5.
Slider Saddle Plate
6.
Safety Latch
7.
Operating Rod
8.
Operating Lever
Fig. 10.9, Taperloc Slide, Manually-Operated Release
Fifth Wheels and Trailer Couplings
10.6