Fontaine Ultra LT series User manual

Fontaine Fifth Wheel
Ultra LT
Service Manual
Fontaine Fifth Wheel • 7574 Commerce Circle • Trussville, AL 35173
©2010 • LT-156 August 2010
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FONTAINE
FIFTH WHEEL®

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Ultra LTUltra LT
Identify fifth wheel assembly
Identify top plate
Identify slides and brackets (Note: see Slides and Bracket section for more information)
Ultra LT Series
Inboard
Adjustable plate mount
Outboard
Contents
Identify your fifth wheel ....................................... 2-3
Slides and brackets ............................................. 4-5
Pre-service procedures........................................ 6-8
Preventive maintenance..................................... 9-10
Uncoupling design ........................................... 11-12
Troubleshooting ............................................... 13-15
Rebuild ............................................................ 16-18
Disassembly .................................................... 19-20
Assembly......................................................... 21-22
Inboard models
will be available
in the future
Indentifying features:
•Fabricatedpullhandle
•Slideassemblieshavecenter-
mounted air cylinders
•Nametagslocatedonfrontskirt

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Identify your fifth wheel
SL 4 LWO 6750 12
Release Top plate model Mounting bracket Mounting height Slide travel
1. Top plate 2. Mounting bracket 3. Slide rail
Fontaine Fifth Wheel complete assembly part numbers. Example: SL4LWO675012
SL = Side left
SR = Side right
AA = Air actuated
4 = Ultra LT Series Actual height from truck
frame to top of fifth wheel.
Examples: 6750 = 6-3/4"
7750 = 7-3/4"
8750 = 8-3/4"
For sliding fifth wheels only.
Example: 12 = 12" slide
24 = 24" slide
36 = 36" slide
48 = 48" slide
LWO = Outboard slide bracket
APB = Adjustable plate bracket
Pending release:
LWI = Inboard slide bracket
SMB = Stationary bracket mount
A36 = Angle mount
Serial number locations
Part number nomenclature
Duty class restrictions
Serial number engraved directly into the right of fifth wheel skirt.
Note: position 5 and 6 of the serial number indicates the year built.
Application/restriction levels
Standard duty: Fifth Wheel must be used in a 100% on-highway
application, with more than 30 miles between each stop. The
total number of towed axles equals two (2). Road type must be
maintained concrete or asphalt. Gross Combination Weight (GCW)
is less than 95,000 lbs or 43,000 kgs. See Fontaine Application
Guide LT-076 for specific application recommendations. Product
used in unapproved applications voids manufacture warranty.
Moderate duty: Fifth Wheel must be used in a less than 10%
off-highway application, with no minimum mileage between each
stop. The maximum total number of towed axles equals four (4).
Road type must be maintained concrete, asphalt, gravel, or crushed
rock. Gross Combination Weight (GCW) is less than 115,000 lbs
or 52,000 kgs. See Fontaine Application Guide LT-076 for specific
application recommendations. Product used in unapproved
applications voids manufacture warranty.
Severe duty: Fifth Wheel can be used in any off-highway
application, with no minimum mileage between each stop. The
total number of towed axles equals five (5) or more. All road types
are acceptable including hard packed dirt and non-maintained
roads. Gross Combination Weight (GCW) is more than 115,000 lbs
or 52,000 kgs. See Fontaine Application Guide LT-076 for specific
application recommendations. Product used in unapproved
applications voids manufacture warranty.
Important application notes:
1. If any single restriction factor within your application
is surpassed within a given duty level, the next duty
level must be selected.
2. When selecting a fifth wheel, if the application or
vehicle usage places the maximum capacity on a
certain fifth wheel, then the selection of a fifth wheel
with a higher capacity is advised. For example, a
tractor that is at a maximum vertical load of 50,000
lbs in a moderate duty application should be using a
fifth wheel with a vertical load capacity of 55,000 lbs
or greater. This additional capacity should give better
service life over a longer period of time.
3. All logging, mining, oil field and similar applications
are considered severe duty. Do not select assemblies
in the standard or moderate levels when a special
application is designated.

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Item Description Part No. Quantity
1 Slide Rail * 1
2 Rear Slide Stop *
*
2
3 Slide Bracket 1
4 Bracket Bushing BSH-3000* 2
5 Air Cylinder * 1
6 Locking Wedge * 2
7 Hex Bolt, 3/8"-16 x 1.25" * 2
8 Spacer Bushing * 2
9 Lock Nut, 3/8"-16 * 2
10 Flat Washer, 1/2" * 2
11 Hex Head Bolt, 1/2"-13 x 1" * 2
1
2
2
3
4
4
5
6
6
7
7
8
8
9
9
10
11
10
11
Fontaine®Ultra LT Series Slides and Brackets
LWO: Outboard slide
• Up to 50 lbs lighter than competitive outboard
slide systems
• 4” slide increments give you slide versatility for
improved payload distribution
• Compact design with central mounted air cylinder
• Booted air cylinder provides protection to shaft
• Available in 6-3/4", 7-3/4", 8-3/4" and 9-3/4"
heights; 12”, 16", 24”, 36” and 48” slide travel
LWO parts list
Item
no. Description Part no. Qty.
1Slide rail –1
2Rear slide stop – 2
3Slide bracket –1
4Bracket bushing BSH-3000 2
5Air cylinder *1
6Locking wedge – 2
7Hex bolt, 3/8"-16 x 1-1/4", gr5 * 2
8Spacer bushing * 2
9Hex lock nut, 3/8"-16, gr5 * 2
10 Flat washer, 1/2" – 2
11 Hex head bolt, 1/2"-13 x 1" – 2
* Included in LWO/LWI air cylinder kit, part no.:
CYL-LWO-LWI
LWO weight chart
Slide
Length
Height
6-3/4" 7-3/4" 8-3/4" 9-3/4"
12" 356 lbs 361 lbs 367 lbs 373 lbs
16" 363 lbs 368 lbs 374 lbs 380 lbs
24" 376 lbs 381 lbs 387 lbs 393 lbs
36" 396 lbs 401 lbs 407 lbs 413 lbs
48" 416 lbs 421 lbs 427 lbs 433 lbs
Add 5 lbs for air actuation

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Fontaine®Ultra LT Series Slides and Brackets
APB: Adustable plate mount
• LT top plate with the ABP bracket is the lightest
mounting system available for the LT family
• Manufactured with the durability and cost-
effectiveness of steel construction
• Brackets are welded to a 3/8" steel plate with
six 5/8" bolt holes on each side for mounting
versatility
• Plate has different cut out and different locations
for rear rocker limit blocks
• Available in 6-1/4", 7-1/4", 8-1/4" and 9-1/4"
heights
LWO weight chart
Slide
Length
Height
6-3/4" 7-3/4" 8-3/4" 9-3/4"
12" 356 lbs 361 lbs 367 lbs 373 lbs
16" 363 lbs 368 lbs 374 lbs 380 lbs
24" 376 lbs 381 lbs 387 lbs 393 lbs
36" 396 lbs 401 lbs 407 lbs 413 lbs
48" 416 lbs 421 lbs 427 lbs 433 lbs
Add 5 lbs for air actuation
APB weight chart
Height
6-1/4" 7-1/4" 8-1/4" 9-1/4"
281 lbs 286 lbs 291 lbs 297 lbs

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Pre-service procedures
Always check for damage due to improper handling or
delivery practices prior to starting recommended pre-service
procedure.
A.Fasteners
Make sure all nuts and bolts are in place and properly
tightened.
Check all welds for cracks, breaks or separation.
Check to see if both bracket pins are in place and secured by
retainer pins and cotter pins.
See Figure A and B.
B. Lubrication
1. Tilt the top plate forward (front of the fifth wheel down) and
apply grease to each bearing area through the zerk fitting
located on each side of the top plate just to the front of the
bracket pins. Continue to apply grease until it is coming out of
the back of the bearing. It may be necessary to raise the rear
of the fifth wheel with a pry bar to open up the pocket slightly
and allow the grease to flow through. Periodically remove
the fifth wheel to clean old grease from the bracket grease
channels to help insure an even distribution of fresh grease.
A substantial amount of grease may be required initially to
fill the reservoir. Tilt the wheel to the rear (rear of the wheel
down) and repeat the procedure. Rock the top plate back
and forth several times to spread the grease over the bearing
surface.
Inspect the trailer kingpin plate and top surface of the fifth
wheel to make sure each is properly greased. A liberal coating
of grease should be applied to the complete surfaces of both
the trailer kingpin plate and the top surface of the fifth wheel.
A paddle or brush will make this job easier.
Do not use a lube plate (high density polyethylene) on top
of the fifth wheel or kingpin bolster plate in lieu of grease
without prior approval by Fontaine.
The additional thickness of this material can prevent the
proper operation of the fifth wheel and can cause a dangerous
condition.
2. Lubricate the fifth wheel lock prior to opening and closing.
Referring to Figure C, grease the jaw and lockbar (wedge) on
top and bottom. Separate the jaw and lockbar (wedge) with
a large screwdriver and distribute the grease along the full
length of the jaw and lockbar (wedge) mating surfaces. Open
and close the fifth wheel several times to further distribute the
grease.
Cotter pin
FigureA
Figure B
Retainer pin
Bracket pin
Grease
fitting
Jaw
Wedge
Separate jaw and
wedge – grease
full length
Grease
fitting
Figure C

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Note: This lock is set from the factory with some running
slack based on a two inch kingpin. If a kingpin is less
than nominal diameter but within tolerance of SAE 1955
the amount of slack will increase. No attempt should be
made to reduce the slack on smaller diameters kingpins
as it would result in failure to close properly around a
nominal kingpin diameter. The adjustment stud can
not be used as knock-out rod! If the fifth wheel is not
properly adjusted the wheel will be very difficult to open.
Once the wheel is opened the adjustment procedure
should be followed by installing a 2" kingpin and the
adjustment stud should receive 2-1/2 turns after contact
with the lock bar.
C. Operation
1. Fontaine’s Ultra LT fifth wheel opens by a straight pull
on the release handle until maximum opening stroke is
achieved then is moved slightly forward until the handle cut
out sets up on the handle block located on the fifth wheel
skirt.
2. Close the locking mechanism using a test kingpin or 2"
(50.8 mm) diameter pipe. Repeat several times making sure
that all moving parts have adequate lubrication.
3. The pull handle grip should always be free of grease or
any substance which could prevent a firm grip, causing the
handle to slip and possibly resulting in injury.
4. Fontaine’s air actuated Ultra LT fifth wheel is shown in
Figure D. A release valve located on the dash or in a lock
box mounted on the rear of the cab is used to activate the
release cylinder. To open, set the tractor parking brake and
pull the release valve. Hold the valve open until the locking
mechanism is locked in the open position. The pull valve
will not activate the air cylinder unless the tractor parking
brakes are set.
Fontaine suggests the use of a moly-based lubricant such as
Mobilgrease XHP320 or equivalent when applying lubricant
to the locking jaw and wedge. Lightly oil other moving parts
in the fifth wheel (areas or regions that experience extreme
and/or prolonged freezing temperatures should consider
using a less viscous substance such as: 90-weight oil, diesel
fuel, kerosene, motor oil, etc. Fontaine suggests contacting
your specific lubricant manufacturer for guidelines on mixing
compatibility of any lubricant).
3. For sliding ffth wheels, lightly oil the locking mechanism.
Operate the mechanism several times to ensure it is
functioning properly.
4. Grease the top plate. Spread grease all over the mating
surface of the top plate. Be sure the grease pockets built into
the top plates are full of grease.
Pre-service procedures
Figure D

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Pre-service procedures
Black arrows are lube points when the fifth wheel is on a mount. However, for proper maintenance it is recommended you clean it
and re-grease the pivot points... see white arrows.
Lubrication points: (Ultra LT)
Jaw and wedge
(see preservice and
lubrication)

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Step2.FunctionInspection
Begin with the fifth wheel in the unlocked position. Pull
handle to unlock fifth wheel if it is not open.
Insert a test kingpin, such as Fontaine Kingpin Tool
KIT-ULTRA-KP, to close the lock.
Make sure the jaw and wedge are engaged behind the
kingpin and the pull handle is fully retracted.
Open and close the wheel again.
If the action is slow or sluggish, it may be due to a build up
of old grease or a bent part causing binding (see trouble
shooting section).
Lightly lubricate the pivot points on the mechanism with a
spray lubricant.
Remember to exercise extreme caution, follow all stated
& customary safety procedures, and be sure to wear
safety glasses.
Step 1. Visual inspection
Using a suitable solvent, degrease the fifth wheel and
mounting brackets every 90 days or 30,000 miles and
inspect for:
1. Cracks in the fifth wheel assembly, mounting brackets,
and mounting parts.
2. Wear and/or damage to moving parts.
3. Correct operation of the secondary lock.
4. Loose nuts and bolts in the fifth wheel and in the
mounting hardware.
5. Securely fastened and properly working springs.
6. Check to see if both bracket pins are in place and
secured by retainer pins and cotter pins.
7. Check the locking jaw. If dimension “X” is less than 0.8"
(20.25 mm) replacement of the jaw and lockbar (wedge)
is required. See Figure A.
Check the fifth wheel operation and adjustment. Using a
test kingpin or 2" (50.88 mm) diameter pipe, follow the
instructions provided in the pre-service procedure on
pages 6-8.
Preventive maintenance
Dimension “X”
Figure A
Step3.Adjustment
1. With the wheel in the closed position, loosen the
adjuster lock nut and turn the adjuster stud counter
clockwise (outward) until it is free from touching the end
of the lockbar (wedge).
2. Insert a test kingpin or 2" (50.8 mm) diameter shaft to
ensure the locking mechanism is completely closed.
3. Turn the adjuster stud clockwise (inward) until it
contacts the end of the lockbar (wedge). Now turn the
adjuster stud clockwise (inward) an additional 2-1/2
revolutions. This will give the recommended .02"
(0.525 mm) running clearance.
4. Tighten the adjuster lock nut.
Improper adjustment can cause the mechanism to bind
and/or wear prematurely.

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Step 4. Lubrication
Lubrication recommended every 6 weeks or 15,000
miles.
Follow the instructions provided in the lubrication
pre-service procedures on pages 6-7.
Special precautions must be taken during cold weather
to ensure that the Fontaine Ultra LT locking mechanism
operates freely. Ice and sludge can built up and lubricants
become thick and binding at low temperatures. In areas or
regions that experience extreme and/or prolonged freezing
temperatures, Fontaine recommends use of a cleaner or
degreaser on the latching mechanism, making sure that the
moving parts operate freely. This should be followed by an
application of 90-weight oil, diesel fuel, kerosene, motor
oil, etc. to all moving parts. This procedure may also be
necessary in operations where excessive road grime or grit
is encountered.
The regular performance of the routine, "90-Day/30,000
mile preventative maintenance procedure," is also
recommended.
Preventive maintenance