Subject: A/C Compressor Tensioner Bracket Retrofit
Field change Program:
Service Bulletin
Coach Section:
16- Heating & A/C

Bulletin Number: Revision:
3143
A
P/N:
08-27-1172

Date:
09/17/2020
Type:
Product Improvement

Application:
Coach Model

Model Year

VIN

J4500

2016 - 2018

65758 - 68800

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.

SI 3143
A/C Compressor Tensioner Bracket Retrofit

1.0

Description
This bulletin outlines steps to add a tensioner bracket to increase the tension on the A/C
Compressor belt.

2.0

Material requirements
ITEM
1
2
3
4

3.0

PART NO
08-27-1386
19-01-1526
19-02-0410
19-03-0497

QTY
1
2
2
2

U/M
EA
EA
EA
EA

DESCRIPTION
Bracket- AC Tensioner
Capscrew- 1/2-13 X 3”
Washer- FL, 1.75 ODX.531 ISX.134, ZN
Nut-Flg, 1/2-13 Yellow Zinc plating

Special tools
Rachet strap (Vendor: U-Line, VPN: H-2068) or MCI Tensioner Compressor tool, P/N:
20-13-6675.
Belt tensioner gauge (Vendor: Napa, VPN: NBR-KR1)
Belt Alignment tool (Vendor: VibrAlign, APN: 100-BH2)

Belt tensioner gauge

Motor Coach Industries Ltd.

Rachet Strap

Belt alignment tool

Page 2 of 6

SI 3143
A/C Compressor Tensioner Bracket Retrofit

4.0

Procedure
Open the engine door using the latch behind the curbside service door.

Rotate the lever
counterclockwise

Use a ratchet strap or MCI tensioner compressor tool, P/N: 20-13-6675, to clasp the AC
belt tensioner. Remove and save the A/C belt.

Remove and save the
belt using ratchet strap
or MCI tensioner
compressor tool, P/N:
20-13-6675

Spring is under compression and in tension.
To prevent personal injury, use caution while using ratchet.

Motor Coach Industries Ltd.

Page 3 of 6

SI 3143
A/C Compressor Tensioner Bracket Retrofit
Remove and discard the nut, washer, and bolt securing the tensioner to the AC
compressor.

Remove and discard
the nut, washer and bolt

Install tensioner bracket, MCI P/N: 08-27-1386, to tensioner using capscrew, MCI P/N:
19-01-1526, washer, MCI P/N: 19-02-0410, and nut, MCI P/N: 19-03-0497, as shown
below. Torque the nut to 89 Ft-Lb.
Nut, MCI P/N: 1903-0497
Install the tensioner
bracket, 08-27-1386

Washer, MCI
P/N: 19-02-0410
Capscrew, MCI
P/N: 19-01-1526

Motor Coach Industries Ltd.

Page 4 of 6

SI 3143
A/C Compressor Tensioner Bracket Retrofit
Secure the other end of the tensioner bracket to A/C compressor using capscrew, MCI
P/N: 19-01-1526, washer, MCI P/N: 19-02-0410, and nut, MCI P/N: 19-03-0497, as
shown below. Torque the nut to 89 Ft-Lb.

Secure the tensioner
bracket to compressor
using washer, 19-02-0410,
screw, 19-01-1526, and
nut, 19-03-0497

Remove the rachet clasp or MCI tensioner compressor tool and re-install the A/C
compressor belt.

Re-install the belt

5.0

Verification
5.1

Belt alignment

Use the belt alignment tool to verify the alignment of the AC compressor pulley to the
pulley on the crankshaft following the instructions in the maintenance manual section
16A-2.

Laser line on the tool

Motor Coach Industries Ltd.

Page 5 of 6

SI 3143
A/C Compressor Tensioner Bracket Retrofit
5.2

Belt tension

Place belt tensioner gauge on top of the belt about 2 inches from the upper pulley, as
shown below. Tension should be 140±5 Ft/Lb.

Belt Tensioner Gauge

End of the procedure

Motor Coach Industries Ltd.

Page 6 of 6