SERVICE BULLETIN
TECHNICAL SERVICE BULLETIN
Bulletin No.:

TSB-049

Date:

July 19, 2023

Subject:

VP Trailer Flex Plate and Sleeve Wear

Models:

Quantum 20’, 40’, 45’ Virtual Pipeline Trailers

Background
Each CNG storage cylinder in Quantum Virtual Pipeline (VP) trailers is mounted to a fixed location at the
top of the trailer.
As the cylinders are pressurized and depressurized, the overall length of the cylinder will change. This
changing length in conjunction with the normal movement of the cylinder within the containment due to
vibration and dynamic road inputs, requires a lower cylinder mounting system that can constantly adjust as
needed.
A flex plate system has been designed to secure the bottom of the cylinders, this flex plate will allow for
normal movement and displacement of the cylinder experienced in normal operating conditions.
Condition
In some cases, the sleeve on the bottom of the cylinder that the lower flex plate is secured to can become
worn to the point that it fails and no longer restrains the bottom of the cylinder.
Cause
In some off highway operating environments, where unusually high levels of debris may be introduced into
the container through the ventilation openings in the bottom of the container, accelerated wear between the
flex plate and the sleeve may occur. This accelerated wear of these components only seems to occur where
lower cylinder mountings are exposed to road splash and debris deposited from the tires. See illustration
on the following pages for the affected areas of the trailer.
Correction
For severe service applications a revised flex plate assembly has been developed.
The revised flex plate assembly has a stainless steel insert to insulate the flex plate material from the
aluminum sleeve. This material change should significantly reduce the accelerated wear experienced due
to heavy contaminate intrusion.
In addition, the flex plate spanner nuts securing the flex plate to the sleeve have been changed to stainless
steel, this will address the wear that can occur between the flex plate and the flex plate spanner nuts. This
will enhance the capability of the flex plate to remain properly clamped and secured to the sleeve.
Inspect the lower cylinder mountings indicated in red by the illustration in this document, if wear is observed
on any cylinder sleeve or flex plate, replace the flex and sleeve on the front outside cylinders with the
revised flex plate assembly.
This revised flex plate assembly will be installed on the front three rows of cylinders, on the right-hand and
left-hand sides above the tractor tires. The replacement of the flex plates in these positions will be
completed at no cost to the customer, on trailers that experience concerns within the standard trailer one
(1) year warranty period.
Because this wear is the result of severe operating conditions and or off highway use, this component is
not covered under any extended warranty.
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Labor Time
Labor OP:
TSB-049

Labor Op Desc.: Inspection- Frt 6 Flex Plates

Time: 1.0 Hrs

VMX3006-TSB

Labor Op Desc.: Flex Plate Sleeve R&R, 107”
Includes lower panel R&R

Time: 1.0 Hrs

Add: Additional lower cover removal for access
Add: Broken Sleeve removal and thread repair
Add: Fender R&R for access
Add: Additional time for 102” cylinders

Time: 0.2 Hrs
Time: 1.5 Hrs
Time: 0.4 Hrs
Time: 1.2 Hrs

Parts Information
Description
* KIT- FLEX PLATE, 102”, SEVERE SVC
* KIT- FLEX PLATE, 107”, SEVERE SVC

Part Number
121952-001
121952-002

Qty
1 per cylinder
1 per cylinder

* Kit includes all parts needed for typical replacement of flex plate and sleeve.
The flex plate kits needed for this update will be available beginning in Late July 2023.
Special Tools
Description
* SKF Axial Lock Nut Socket
SOCKET- CYLINDER SLEEVE, VP
CROW FOOT- CYLINDER SLEEVE, VP, 102"
THREAD CHASER- M56 X 2

Part Number
SKF TMFS-12
702603
702197
702624

The tools listed in this table are recommended to properly complete this repair.
* Tool is commercially available and is not in stock at Quantum.
Application
All Quantum 20’ VP trailers Gen 1
All Quantum 40’ VP trailers Gen 1-3
All Quantum 45’ VP trailers Gen 5-7

Contact Information:
E-Mail: [email protected]
[email protected]
Phone: 800.816.8691

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TECHNICAL SERVICE BULLETIN
Dirt and debris from the road is picked up by the tires and thrown into the container mountings through the
vent openings in the lower panels. This continuous contaminate introduction is responsible for the
accelerated wear of the components in this area.
The outside cylinders in the front of the trailer (shown in red), are typically impacted by this concern due to
the proximity directly above the tractor tires. To date there have been no reported wear concerns of flex
plates or sleeves on the center cylinders in the front of the trailer.
The cylinders in the center of the trailer near the rear (shown in yellow) may experience accelerated wear
due to splash from the trailer tires, but to a much lesser extent.
The fenders on the trailer itself protect the cylinders directly above the trailer tires.
FRONT

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FRONT

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TECHNICAL SERVICE BULLETIN
Flex Plate and Sleeve Inspection
1. Remove the lower cover assembly for the
cylinder(s) being inspected.
2. Inspect for evidence of movement between the flex
plate and the flex plate nut. In the picture to the
right there is a witness mark on the flex plate
caused by the nut due to movement.

Movement may also be detected by a black
residue on the flex plate around the flex plate nut.

3. Attempt to move the cylinder assembly and check
for movement between the flex plate and the flex
plate nut and sleeve.
Any visible movement indicates wear is present
and the assembly should be serviced.

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Flex Plate Sleeve Replacement
IMPORTANT: If the flex plate sleeve, lock nuts or hardware is damaged where the
adjustments cannot be measured prior to disassembly, the cylinder pressure MUST be
under 500 psi (3447 kPa) before beginning this procedure.
1. Remove and retain the lower cover assembly and
hardware.

2. Loosen the set screw locking the flex plate spanner
nut in position, then remove the flex plate spanner
nut.

3. Remove and retain the eight (8) flex plate retaining
nuts, remove and retain the flex plate.

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IMPORTANT: On some cylinders the sleeve jam nut may not be present, and the sleeve is
tightened against the cylinder boss, or the jam nut and sleeve are tightened up to the
cylinder boss. If no sleeve jam nut exists, or jam nut and sleeve are against the boss, install
the new sleeve or sleeve and jam nut in the same manner and torque the new sleeve against
the cylinder boss.
This measurement will be necessary for proper reassembly.
4. Measure and document the distance from the
cylinder boss to the bottom edge of the sleeve jam
nut, reference A in the illustration.
IMPORTANT: If this sleeve replacement
procedure must be completed on a cylinder
with more than 500 psi (3447 kPa), measure and
document the position of the top flex plate jam
nut from the bottom of the cylinder dome.
This measurement will be necessary for proper
reassembly.
5. Measure and document the distance from the cylinder boss to the bottom edge of the upper flex
plate spanner nut, reference B in the illustration.

Care must be taken to not disturb or turn the cylinder adapter in the cylinder boss
during cylinder sleeve removal. This may result in cylinder damage or an
irreparable leak. Make sure to inspect for the presence of both adapter pins prior to
removal of the cylinder sleeve.
Failure to follow these instructions will result in death or serious injury.
6. Before removing the cylinder sleeve a cylinder
adapter pin inspection MUST be completed. Use
the following steps:
NOTE: If the sleeve jam nut or the cylinder sleeve
is tightened all the way against the cylinder boss,
the cylinder adapter pins may not be visible and
are assumed to be in place.
If the cylinder pins are visible use the following
steps:

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•

Looking at the bottom of the cylinder, verify the
locating pins in cylinder adapter are present. Use
of an inspection mirror may be required.

•

If both pins are not present, install a pin using a
3/16” diameter, ¾” long pin in place of missing pin.
A ¾” long pin will protrude slightly even if fully
seated,

•

If required, the cylinder sleeve jam nut (if present)
may be threaded up to secure the pin in place.

•

Failure to ensure the cylinder adapter is properly
secured could result in loosening of cylinder
adapter. This will result in an irreparable leak past
the seals in the cylinder adapter.

7. Loosen the sleeve jam nut securing the cylinder
sleeve by turning clockwise.
8. Remove the cylinder sleeve from the cylinder
adapter by turning counterclockwise.
If the cylinder sleeve does not spin off by
hand, a pipe wrench of up to 18” may be
used to help aid removal. Do NOT use any
wrench over 18”.

Do NOT apply a turning force of more than 295 ft lbs. (400Nm) to the cylinder sleeve
or the cylinder may be damaged resulting in severe personal injury or an irreparable
leak. Failure to follow these instructions will result in death or serious injury.
If the sleeve does not spin off easily or
has been damaged, STOP! Refer to
Damaged Sleeve Removal procedures
or contact Quantum for guidance.
9. Install the new cylinder sleeve and adjust until it is
in the same position as the original sleeve
measured in step 4.
10. While holding the cylinder sleeve in position,
tighten the sleeve jam nut. It is also acceptable to
hold the jam nut and using tool 702603 or
equivalent tighten the sleeve.
Tighten to 148 lb ft (200 N.m.)

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IMPORTANT: If this sleeve replacement procedure is being completed on a cylinder with
more than 500 psi (3447 kPa), install the sleeve to the previously measured position and
skip this step.
11. Place a straight edge across the bottom of the container floor and measure the distance from the
bottom of the container floor and the bottom edge of the sleeve.
If the distance is less than 0.394” (10mm) adjust the sleeve installed height.

12. Thread the upper flex plate spanner nut up the
sleeve until it is approximately flush with the weld
nuts.
Note: The stainless steel flex plate nuts are
radiused on both sides.
IMPORTANT: If cylinder pressure is more than
500 psi (3447 kPa), adjust the top flex plate
spanner nut to the position measured during
disassembly and proceed to the next step.
Otherwise proceed with this step.
13. Holding the sleeve support tool 702210 in place
tightly against the weld nuts, adjust the upper flex
plate spanner nut until it touches the tool.
If support tool 702210 is not available, fit the flex
plate with the proper mounting hardware into
position. Tighten the mounting hardware so the flex
plate is held firmly in position.
Adjust the upper flex plate spanner nut until it is
0.197” – 0.315” (5mm – 8mm) from touching the
top of the flex plate.
Remove the flex plate and hardware.

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14. Install a set screw in the upper flex plate spanner
nut to secure the flex plate nut in position.
Tighten set screw to 14 lb.in. (16 dN.m.)

IMPORTANT: Depending on the vintage
of the trailer being serviced, the upper
support hardware may be spacers or
nuts and washers. Ensure any
supporting hardware is in place for this
step.
15. Place a spacer over each stud and then place the
flex plate over the studs; move the cylinder as
necessary to align the cylinder sleeve to the center
of the flex plate.

16. Use the 702208 alignment tool or equivalent as
needed to move the cylinder to align with the hole
in the flex plate.

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17. Even when aligned, it may be difficult to install the
flex plate over the cylinder sleeve due to minor
alignment issues.
Use the 702209 installation tool or equivalent and
a small dead blow hammer to fully seat the flex
plate over the cylinder sleeve.

18. Install washers and four (4) flex plate retaining nuts
over the studs and tighten the flex plate retaining
nuts.
Tighten to 59 lb ft. (80 N.m.)

19. Install the lower flex plate spanner nut, verify the
side of the nut with the radius is facing the flex
plate.
Note: The stainless steel flex plate nuts are
radiused on both sides.
IMPORTANT: Note that the flex plate spanner
nut torque specification is higher than the
torque specification for flex plates without
inserts.
Tighten to 85 lb ft. (115 N.m.)

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IMPORTANT: If cylinder pressure is
more than 500 psi (3447 kPa), the offset
specification noted in this step is not
applicable. Proceed to the next step.
20. Measure the offset between the two surfaces of the
flex plate in the location shown, the offset must be
between 5mm – 8mm.
If the flex plate offset is not within this
specification, adjust the upper flex plate
spanner nut as needed.
21. Install a set screw in the lower flex plate spanner
nut and secure the nut in place.
Tighten to 14 lb.in. (16 dN.m.)

22. Install the remaining four flex plate retaining nuts
over the studs and tighten.
Tighten to 59 lb ft. (80 N.m.)

23. Install any removed lower covers:
Tighten to 22 lb ft. (30 N.m.)

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