SB 3131

Subject: Replacing Adapter Plates on Tag Axle Bellows
Field change Program:
Service Bulletin
Coach Section:
12- Suspension
Bulletin Number: Revision:
3131
A
P/N:
12-03-1492
Date:
03/20/2020
Type:
Product Improvement
Application:
Coach Model
Model Year
VIN
J4500
All coaches beginning with MY 2013, VIN: 66554
Read this entire procedure before beginning work.
Use Safe Shop Practices at All Times.
To avoid personal injury:
a. Proper Personal Protective Equipment (PPE) must be worn. Safety glasses and
protective gloves are required for working with DEF Fluid.
b. Turn the main battery disconnect switch to the OFF position.
c. Ensure that both the front and the rear wheels are chocked.
d. Position the ENGINE RUN and ENGINE START switches on the engine
compartment remote control box to the OFF position.
e. Allow enough time for components to cool down prior to working in the engine
compartment.
SERVICE BULLETIN 3131
Replacing Adapter Plates on Tag Axle Bellows
1.0
Description
This procedure outlines steps to replace the adapter plates on the tag axle bellows to
increase support for the bellow piston.
2.0
Material requirements
ITEM
1
2
3.0
PART NO
6479895
6479894
QTY U/M
2
EA
2
EA
DESCRIPTION
Plate- Adapter, Tag axle bellow
Washer- Tag axle bellow
Special Tools
No special tools required.
4.0
Procedure
Lift the coach at the rear tag axle jacking points following the instructions in section 3F in
the MCI J4500 Maintenance manual.
Lift the coach at the
rear jacking points
Motor Coach Industries Ltd.
Page 2 of 6
SERVICE BULLETIN 3131
Replacing Adapter Plates on Tag Axle Bellows
Remove and save the ten nuts on the hub cover of the driver side tag axle wheel. Save
the hub cover
Remove and save the
hub nuts and hub cover
Remove and save the ten flange nuts on the wheel. Remove and save the wheel.
Remove and save the
flange nuts
Tire and wheel assemblies weigh more than 200 lbs.
To prevent personal injury, use caution when loosening the wheel nuts, and when
lifting the wheel off the hub.
Motor Coach Industries Ltd.
Page 3 of 6
SERVICE BULLETIN 3131
Replacing Adapter Plates on Tag Axle Bellows
Dump the air off the coach using the suspension air drain valve.
Pull the air drain
valve to dump the
air off the coach
Remove and save the nut and washer securing the tag axle bellow to the tag axle.
Remove and save
the nut and washer
Remove and discard the adapter plate.
Remove and discard
the adapter plate
Motor Coach Industries Ltd.
Page 4 of 6
SERVICE BULLETIN 3131
Replacing Adapter Plates on Tag Axle Bellows
Install the bellow washer, MCI P/N: 6879894, to the bellow as shown below.
Install the bellow washer,
MCI P/N: 6879894
Install adapter plate, MCI P/N: 6479895, to the bellow.
Install adapter plate,
MCI P/N: 6479895
Install the modified bellow to the axle using the existing washer and nut. Torque the nut
to 45 Ft-Lb.
Install bellow using
nut and washer
Install the wheel using existing flange nuts and hand tighten the nuts.
Install the wheel
using flange nuts
Motor Coach Industries Ltd.
Page 5 of 6
SERVICE BULLETIN 3131
Replacing Adapter Plates on Tag Axle Bellows
Torque the nuts to 450-500 Ft-Lb in the sequence shown below.
Sequence of the
nuts to torque
Install the hub cover using the existing nut covers. Turn the nut covers approximately five
full turns until the nut cover clamps the hub cover tightly against the wheel.
Install the hub cover
using nut covers
Repeat the steps on the passenger side (curbside) tag axle wheel.
End of the procedure
Motor Coach Industries Ltd.
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