Field Service Bulletin
MDA-Series CNG Refuse Roof Mount System
Upper Doors Rubbing Against Cylinders

ENP-384
May 4, 2015

1. Introduction
WARNING
If the vehicle has been in an accident, the cylinders and
fuel system must be examined by a qualified inspector.

Figure 1 Left: Evidence of rubbing against cylinders on the underside of the top cover. Red
circle: When repairing holes with welds, make sure to grind the surface smooth to reduce
effects of rubbing on cylinders. Right: Slots for mounting bolts may allow cover slippage
and contact with fuel cylinders.
Refer to Figures 1 and 2. The upper covers on some 2005 refuse roof mount systems (MDA-Series
from Fab Holdings) are rubbing against the fuel cylinders.
Over time, the abrasion can cause damage to the fuel cylinders, see Figure 2. If left un-checked,
the abrasion will worsen and cause un-repairable damage. Remember, a certified (CGA C-6.4) or
other qualified CNG fuel system inspector must make this assessment.

Figure 2. Abrasion damage to fuel cylinders from upper doors.

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First, make sure the center cover support under the center of the cover is in place. This piece is
necessary to prevent the top panel from flexing. See Figure 3. It runs parallel to the cylinders inside
the cabinet. If the cover support (part number MDP-1000819) is not present, contact Agility Fuel
Systems Product Support Group.

Center cover
support

Figure 3. Make sure the center cover support is in place to prevent the top cover
from flexing.
If the cover support is in place and the panel is still rubbing against the cylinders, a modification is
needed to increase the clearance inside the CNG system cabinet: New holes and nut clips will be
used to re-locate the cover and add more clearance.

2. Affected Units
Some MDA-Series refuse roof mount systems produced in early- and mid-2005.

3. Tools, Materials and Required Parts
1.
2.
3.
4.
5.
6.
7.

Center punch
Drill motor
7/16-in. drill bit
9/16-in. drill bit
1-1/2-in. hole saw
Agility Fuel Systems 3/8-in. nut clips, part number 10700213, or equivalent, as needed
Grade 8 bolts, yellow zinc plated, 3/8-16 x 1-1/4-in., part number 10700049, as needed

4. Procedure
WARNING
1) Wear appropriate PPE and fall arrestment gear when servicing roof-mounted systems.
2) Check for clearance behind panels and housings before drilling any holes.
1. There is no need to depressurize or defuel the system for this procedure.
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2. Refer to Figures 3 and 4. Loosen all 3/8-in. top cover mounting bolts at the front and rear of
the cover assembly and slide the cover to the top of the bolt slots to increase clearance
inside the housing. Front nose: 7 bolts. Rear: 5 bolts.

Figure 4. Loosen the cover mounting bolts at each end, and lift the cover upwards. There
are 7 holes in the front and 5 holes in the rear.

Drill new cover mounting holes 4-in. inward (toward the center) of the
existing slots in two places on the front and rear ends of the cover (+)

+

+

Figure 5. Use the existing cover holes (slots) for reference to determine new hole locations.
3. Lift the cover to the highest possible location – to the top of the cover slot.
4. Retighten bolts to secure cover and hold it in place.
5. Center punch two hole locations 4-in. inward of the outer most existing cover slots (see
Figure 5).
6. Drill through the cover and the first wall of the frame tube with a 7/16-in. drill bit.
NOTE: Make sure to drill through one wall only.

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7. Remove all cover bolts and remove the cover to expose the frame. Move the cover to a
safe place and continue.
8. Drill out the new frame holes to 9/16-in.
9. From the center of each 9/16-in. hole measure inward 1-7/8-in. and center punch.
10. Make a hole for the clip nut fastener with a 1-1/2-in. hole saw, see Figure 6.
11. Slide a clip nut fastener into the 1-1/2-in. hole on the rail and align the threaded end to the
9/16-in. hole in the cover, see Figure 7.
12. Paint any bare metal sections.
13. Re-install cover and bolts then tighten bolts. Torque: 84-in.Lbs

Figure 6 Install the nut clips into the 1-1/2-inch hole . . .

Figure 7 . . . and align the threaded portion with the holes in the cover.

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Figure 8 The cover bolts to the front and rear of the system frame.

5. Warning Messages Used in this Bulletin

WARNING
Personal injury or death may occur if procedures are not followed

6. Warranty Information
1. Normal warranty period and policy applies.
2. Standard repair time (SRT) for this procedure is 1.5 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
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

A. Bhakta

5/4/15

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