Field Service Bulletin
Behind the Cab
Cabinet Isolator Replacement
ENP-357
March 3, 2015

1. Introduction
A rubber isolator is used between the vehicle chassis and Agility Fuel Systems behind the
cab (BTC) cabinet to dampen vibration (see Figures 1 and 2). The isolator is a routine
maintenance item, but service lifetime for this isolator varies widely.
Based on previous experience with 225xxxxx systems, we have recommended replacing
these very 5 years. On most 225 systems the rubber isolators last 15 years.
Figure 1 shows a rubber isolator in good condition. The vehicle has 316,000 miles and has
been in service for four years.
If there is metal-to-metal contact between the vehicle chassis and the CNG system frame,
the isolators must be replaced, see Figure 3.

Figure 1 Rubber isolator between the BTC cabinet and vehicle chassis on a four year old
system with 300,000-plus miles. A quick look indicates the rubber pad is in good condition.

Figure 2 One rubber isolator (part number 22400136) is placed under each cabinet mounting
bracket as shown.

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Figure 3 Metal-to-metal contact between the vehicle chassis rail and the fuel system cabinet
can be seen in this picture. This isolator should be replaced.

2. Affected Units
Agility Fuel Systems behind the cab (BTC) CNG systems with rubber isolator pads
between the vehicle chassis and the fuel system cabinet: 4-tank 16x80 60 DGE system
(224xx000 series family of part numbers) 5-tank 16x80 75 DGE system (225xx000 series
family of part numbers) 3-tank 21x86 75 DGE system (203xx000 series family of part
numbers) 4-tank 21x86 100 DGE system (203xx000 series family of part numbers).

3. Tools and Materials
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Lift or hoist, rated at least 3,000 lbs.
Torque wrench
Leak detection fluid
New isolators, if needed. Replace both pairs (4 isolators) at the same time. Agility
Fuel Systems part number 22400136.

WARNING
Depressurize and defuel the system before performing this procedure.

NOTE
Consume as much fuel as possible, since the system must be defueled.

4. Isolator Replacement Procedure

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5. Procedure – Isolator Replacement
1. Depressurize system.
2. Defuel the system as an added precaution and to reduce system weight.
3. Remove all plumbing connections at the fuel system chassis and plug them to
prevent contamination and debris entry.
4. Prepare lift hoist (capacity 3000 lbs minimum).
5. Remove all vehicle chassis to fuel system frame mounting bolts (see locations on
Figure 2, red arrows.)
6. Lift fuel system up and away from vehicle.
7. Remove the worn isolator and clean mating surfaces.
8. Replace with new isolators.
9. Lower system onto chassis.
10. Tighten mounting bolts to an initial torque of 200 Ft-Lbs for three cycles, following
the torque pattern in Figure 4.

Figure 4 Torque pattern and sequence for BTC mounts.

a. Initial torque: 200 Ft-Lbs.
b. Four hours after initial torque: 200 Ft-Lbs.
c. Minimum of 4 hrs after second torque: 200 Ft-Lbs.
d. Minimum final bolt torque after the rubber has settled: 159 Ft-Lbs.
11. Re-connect plumbing components and connections.
12. Check for leaks and fix as needed.
13. Enter service information on fuel system inspection decal or vehicle service records.
14. Return system to normal operation.

6. Warranty Information
Standard warranty coverage period applies. Standard repair time (SRT) is 4 hours.
If you have any questions, contact Agility Fuel Systems Product Support at 949-267-7745 or
[email protected].
Agility Fuel Systems
Product Support
1815 Carnegie Ave
Santa Ana, CA 92705 USA

Proprietary Statement
The information provided within this document is proprietary and confidential. All prior versions,
including updates and revisions forwarded separately, are proprietary. The information provided by
Agility Fuel Systems to its customers and clients is solely for the use of those customers and
clients. No portion of this manual may be reproduced or distributed without express written consent

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of Agility Fuel Systems. Agility Fuel Systems reserves the right to utilize the intellectual property
contained within this publication as content for any other publication produced by Agility Fuel
Systems.
Trademark Notice
Agility Fuel Systems® is a registered trademark of Agility Fuel Systems. Drop-N-Go™ is a
trademark of Agility Fuel Systems. Trademarks of other manufacturers are the property of their
respective companies.
Revision

Description

Author

Approved By

Date

--

Initial Release

W. Yoshida

C. Forsberg

3/3/15

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