PREVOST X3-45 COMMUTER User Manual

SECTION 11: REAR AXLES
12
DOB 1300-1556 | X3-45 Commuter PA-1648 Maintenance Manual Section 11 revised Jan 2021
3. TAG AXLE
The tag axle is located behind the drive axle. It
carries a single wheel and tire on each side.
The system allows unloading of the tag axle air
springs without raising the axle for the following
purposes:
1. Shortening of wheelbase, thus allowing
tighter turning in tight maneuvering
areas such as parking lots or when
making a sharp turn.
2. Transferring extra weight and additional
traction to the drive wheels on slippery
surfaces.
Refer to the "OPERATOR'S MANUAL" for
location of controls
The tag axle service brakes operate only when
the axle is in normal driving (loaded) position.
3.1 UNLOADING TAG AXLE
To reduce the turning radius, the air springs
pressure will be automatically reduced by 75%
when the coach is moving at speed lower than 5
mph (8 km/h) and with more than 1½ turn from
the steering.
3.2 TAG AXLE WHEEL BEARINGS
The unitized hub bearings used on the tag axle
are pre-adjusted, lubricated and have seals
fitted as part of the manufacturing process. The
bearings are greased for life and there is no
need or facility for re-lubrication.
MAINTENANCE
Front and tag axle hub bearings need to be
checked
at the intervals specified by the
Lubrication And Servicing Schedule in Section
24A: LUBRICATION & SERVICING
SCHEDULE.
3.3 REMOVAL AND REINSTALLATION
3.3.1 Removing Tag Axle Only
The following procedure deals with the removal
of the tag axle while keeping the air springs
installed. The method used to support the axle
and suspension components during removal
and disassembly depends upon local conditions
and available equipment.
1. Connect an external air pressure line to the
emergency fill valve in the engine
compartment.
2. Lift the axle by pushing the lever forward.
WARNING
Install a protective cover to prevent
unfortunate lever operation while work is being
carried out under the vehicle.
3. Disconnect tag axle air springs pneumatic
hoses and install valves or plugs.
4. Raise the vehicle using the lifts.
5. Dismount tag axle components.
6. Before reinstalling air spring hoses, make
sure there is no pressure left inside by
opening the valves or unloading tag axle.
3.3.2 Removing Tag Axle Along With
Suspension Components
The following procedure deals with the removal
of the tag axle assembly along with the
suspension components. The method used to
support the axle and suspension components
during removal and disassembly depends upon
local conditions and available equipment.
1. Raise vehicle by its jacking points on the
body (Figure 5) or see Section 18, "Body"
under heading: "Vehicle Jacking Points").
Place jack under frame.
2. Remove drive axle wheels (if required, refer
to Section 13, "Wheels, Hubs And Tires").
3. Exhaust compressed air from the air supply
system by opening the drain cock on each

PREVOST X3-45 COMMUTER Specifications

General

Engine	Volvo D13
Transmission	Allison B500
Fuel Type	Diesel
Length	45 ft (13.7 m)
Width	102 in (2.6 m)
Horsepower	500 hp
GVWR	54, 000 lbs
Height	141 in