LITERATURE NUMBER
MPD 70381
FOLDING HITCH BALL
9
OPTIONAL UNDER TRUCK
INSTALLATION KIT
AENGLISH •Installation •Operation •Maintenance
Effective 11/21/07
REFERENCE NUMBERS REFER TO ILLUSTRATIONS ON PAGE 4.
SAFETY ALERT SYMBOLS
Safety Symbols alerting you to potential personal safety hazards. Obey all safety
messages following these symbols.
WARNING CAUTION
avoid possible avoid possible
injury or death injury and/or property damage
FOR YOUR SAFETY READ ALL INSTRUCTIONS
BEFORE INSTALLATION AND OPERATION
Installer: Provide these instructions to the consumer.
Consumer: Keep documents for future reference.
WARNING
PERSONAL INJURY / PRODUCT DAMAGE
• Know the trailer weight and added load weight. Do not exceed
the capacity of the coupler, ball or stem, whichever is lower.
Do not exceed the towing vehicles rated towing capacity.
•
• For adequate transfer of forces produced during towing these
instructions MUST be followed.
1. Raise truck at frame so that the weight will be taken off the suspension and rear wheels will be away from wheel well openings. This
will give more access to the side of the truck frame where the
mounting plates will be installed.
VEHICLES EQUIPPED WITH EXHAUST HEAT SHIELDS AND/OR WHEEL WELL LINERS -
2.
Temporarily remove shields and liners to provide adequate space for
installation of long cross angles and side frame mount brackets.
Keep these parts for replacement after hitch installation.
3. Place carriage bolts in square holes at the ends of the angles.
4. Slide cross angles (long) in between frame and bed under the vehicle, one end at a time (the downward portion of the angles will be
facing each other)
5. Insert side frame mounting brackets (end with slots) from side of vehicle between vehicle frame and angles installed in previous step
6. Loosely bolt cross angles to side frame mount bracket (14˝ long) FIG 5.
INSTALLATION
CAUTION
VEHICLE DAMAGE
FIG 3 & 4.
FIG 5.
FOLDING HITCH BALLS
The Atwood Folding Hitch Ball is a hitch ball designed to be mounted
on a pickup truck, positioned above and forward of the rear axle for
towing gooseneck type trailers.
Max. Gross Vehicle Weight: 25,000 lbs.
For larger trucks, contact the vehicle manufacturer or Atwood
Mobile Products for recommendations.
To adequately transfer towing forces to the truck, the folding hitch ball
must be supported by a structure that ties the folding hitch ball into
the truck frame. The Atwood Under Truck Installation Kit is a complete
bolt-on support structure. Fabrication instructions for an alternate support structure using the Bed Plate or H Frame method of installation
are also included.
Ball Size: 2-5/16˝ diameter
Tongue Load: 5,000 lbs.
ATWOOD UNDER TRUCK INSTALLATION KIT
Use Installation Kit with Atwood Folding Hitch Ball
TOOLS REQUIRED:
Drill with 3/4˝, 7/16˝ bit Hammer Torque Wrench
9/16˝ wrench & sockets Center Punch
15/16˝ wrench or sockets Saber Saw
INSTALLATION PARTS:
QTY DESCRIPTION
2 CROSS ANGLES (LONG PARTS)
2 SIDE FRAME MOUNT BRACKET (14˝)
1 BOLT PACK
8-CARRIAGE BOLTS 3/8˝ X 2˝ GRADE 5 ZINC PLATED
STANDARD BOLTS 3/8˝ X 1-3/4˝ GRADE 5 ZINC PLATED
816-WASHERS 3/8˝ X 1 ZINC PLATED
16-NYLON LOCK NUTS 3/8˝ GRADE 5 ZINC PLATED
4 SPACERS
CAUTION
VEHICLE DAMAGE
• The center of the ball must be 2˝ to 6˝ in front of axle centerline.
• The position of the ball must allow for proper clearance between
trailer and both rear of cab, and rear corner of truck bumper when
making turns of up to 90°.
7. Position the center of the frame mount brackets 2˝- 6˝ forward of the
rear wheel axle centerline (providing adequate clearance for brake,
electrical and fuel systems)
8. Center the long cross angles on the vehicle from right to left. This is
key to having the folding ball assembly centered in the bed
Check installed cross angles to be sure that they are square with
the truck frame.
FIG 6.
FIG 4.
WARNING
PERSONAL INJURY / VEHICLE DAMAGE
• DO NOT CUT gas lines, brake lines, electrical wiring, etc. when mak-
ing cutouts or drilling holes in truck.
9. From the under side of pickup truck, mark the center of holes in
bed using the hitch as a template. Drill holes to fit carriage bolt
using a 3/4˝ drill bit
10. Before cutting 12-7/8˝ x 8˝ hole in bed of vehicle be sure to recog-
nize the hole must be offset 2-1/8˝ towards the driver’s side for ball
to be centered in truck bed
11. Make cutout on the floor of truck bed. See FIG 1 & 2.
FIG 4.
FIG 2.
1
12. Bolt the folding hitch ball assembly to installation kit through the
truck bed using (4) four, SAE Grade 5, 5/8˝ carriage bolts, nuts and
lock washers (supplied with Atwood folding hitch ball). Shim (not
supplied) as necessary to accommodate corrugation in floor of
truck bed.
13. Check operation of ball and safety chain attachments. Make
adjustments to allow for free operation of parts. Tighten 5/8˝ car-
riage bolts to 150 (ft.lb) torque.
14. The tops of the steel angles must fit flush against the underside of
the truck bed. The frame mount brackets and/or spacers must fit
against the outside of the truck frame for proper installation.
15. Mark the center of the mounting holes being used with center
punch.
16. Check inside frame before drilling to be sure no lines or wiring will
be damaged by drill.
17. Drill (4) four holes on each side of vehicle using 7/16˝ drill bit.
18. Use spacers as needed
FIG 7.
19. Tighten all 3/8˝ bolts to 33 (ft.lb) torque. Failure to tighten bolts as
described may result in fastener loss or failure.
20. Replace wheel well liners and heat shields to original locations in
reverse order if removed.
21. Proceed to
INSTALLATION CHECK.
H-FRAME METHOD - FIG 8
The H-Frame support structure consists of
2 - support structures 6˝ by width of truck frame x 1/2˝ thick 8-G
2 - support structures 6˝ x 8˝ x 1/2˝ thick 8-H
2 - stiffener angles 2˝ x 2˝ x 26˝ long x 1/4˝ thick 8-E
4 - frame brackets 2˝ wide x 3/8˝ thick 8-F
CAUTION
VEHICLE DAMAGE
• For adequate transfer of forces produced during towing these
instructions MUST be followed.
WELDING INSTRUCTION
• M.I.G. OR STICK - 5/32˝ fillet weld minimum.
• M.I.G. WELDING - Use A.W.S. ER 70S-3 or 6 wire or equivalent with a
diameter of .035 - .045. The recommended shielding gas mixture is
75% - 95% Argon & 25% - 5% CO2.
• STICK WELDING - Use E6011 A.W.S. welding rod or equivalent with a
diameter are as follows: 1/8” electrode set power between 115-130
Amps DC or 5/32” electrode set power between 140-160 Amps DC.
The installer must make his own H-frame, stiffener angles, and frame
brackets. Use structural quality hot rolled or cold rolled steel bar. All
steel used must meet minimum ASTM A-36 specifications.
1. To form H-Frame support - Weld support structures
FIG 10-G and
10-H together with 1/4˝ uninterrupted fillet square butt joint welds on
both sides of the plates
FIG 10-A.
2. Weld stiffener angles (FIG 8-E) to bottom of H-Frame using 1/4˝ fillet
1˝ - 2˝ skip weld full length of each stiffener angle on both sides of leg
FIG 10-B. Stiffener angle may also be through bolted with 4-1/2˝
Grade 5 bolts. Tighten to 60 (ft.lb) torque.)
3. MOUNTING LOCATION AND TRUCK BED FLOOR CUT-OUT
Proper mounting location for folding hitch ball to distribute weight
properly between truck axles -
a. Center BALL between sides of truck bed floor,
b. Locate BALL 2˝ to 6˝ in front of rear axle centerline
FIG 1-A
FIG 1-A
4. Before cutting 12-7/8˝ x 8˝ hole in bed of vehicle be sure to recognize the hole must be offset 2-1/8˝ towards the driver’s side for ball
to be centered in truck bed FIG 2.
5. Make cutout on the floor of truck bed FIG 1 & 2.
6. Put Folding Hitch Ball in truck bed, align with cutout in floor of bed
FIG 8-A & 9.
7. Mark holes to be drilled on truck bed using holes in folding hitch
ball as a guide for locations. Drill 11/16˝ diameter holes.
8. Place H-Frame FIG 8-G/H under floor of truck bed and above frame
of truck. Align with cutout in floor of truck bed. Clamp in place
against bottom of bed.
9. Drill four holes in H-Frame using holes previously drilled in truck
bed for a guide.
10. Bolt the folding hitch ball assembly and H-Frame to the truck bed.
Use (4) four, SAE Grade 5, 5/8˝ carriage bolts
FIG 8-D, nuts and
lock washers (supplied). Shim as necessary to accommodate corrugation in floor of truck bed.
11. Tighten 5/8˝ nuts to 150 (ft.lb) torque.
12. The tops of the steel frame brackets must fit flush against the
underside of the truck bed. The inside of the steel frame brackets
must fit flush against the truck frame for proper installation.
WARNING
VEHICLE DAMAGE
• Mounting brackets must be bolted to frame. Welding will NOT pro-
vide the structural strength needed for towing and may void factory
warranty on vehicle.
13. Position the frame brackets along each side of the truck frame
providing clearance to any crossmember, fuel line, electrical or
brake system. Drill 17/32˝ (.531˝) diameter holes through truck bed
and H-frame.
14. Secure the frame brackets to the truck bed and H-Frame with SAE
Grade 5, 1/2˝ diameter bolts, nuts and lock washers (not supplied).
15. Drill two (2) 17/32˝ (.531˝) diameter holes through the lower leg of
the frame brackets and truck frame. Position the holes in vertical
center of the truck frame.
16. Secure frame brackets to the truck frame with 2 each SAE Grade 5,
1/2˝ dia. bolts, nuts and lock washers (not supplied).
17. Tighten all 1/2˝ bolts to 60 (ft.lb) torque.
18. Proceed to
INSTALLATION CHECK.
2
BED PLATE METHOD - FIG 11
The Bed Plate support structure consists of
1 - bed plate 26˝ x 44˝ by 3/8˝ thick 11-G
2 - stiffener angles 2˝ x 2˝ by 26˝ long x 1/4˝ thick 11-E
6 - L shaped frame brackets 2˝ wide x 3/8˝ thick 11-F
CAUTION
VEHICLE DAMAGE
• For adequate transfer of forces produced during towing these
instructions MUST be followed.
The installer must make his own bed plate, stiffener angles, and L
shaped frame brackets. All steel used must meet ASTM A-36 steel
specifications. Bed plate must be structural quality, hot-rolled steel
plate. Stiffener angles must be 2˝ x 2˝ x 1/4˝ steel bar size angles.
1. Layout and cut bed plate cutout (like truck bed)
2. Center bed plate in bed of pickup truck FIG 1 & 11.
3. Align cutout in bed plate
4. Place folding hitch ball assembly into hole in bed plate and pick-up
truck bed floor. Arrow and “FRONT”stamped into the top plate of
folding ball assembly must point to cab of truck FIG 1-A.
5. Drill 11/16˝ diameter holes through bed plates and truck bed to
secure folding hitch ball to bed plate. Use holes in base of folding
hitch ball as a guide for hole locations.
6. Bolt the folding hitch ball assembly to the bed plate and truck bed.
Use the four supplied SAE Grade 5, 5/8˝ carriage bolts
nuts and lock washers. Use flat washers (not supplied) on the
underside of the truck bed to help distribute the load evenly.
7. Tighten all 5/8˝ nuts to 150 (ft.lb) torque.
8. Position the 2 stiffener angles
bed using frame brackets
bed and bed plate.
NOTE: It may be necessary to shift the stiffener angles front or back to
clear any truck bed crossmembers.
9. Drill holes at the front and rear end areas of the bed plate to mount
the 2 stiffener angles. Holes must be 17/32˝ (.531˝) diameter.
10. Secure each stiffener angle to underside of truck bed with 4, SAE
Grade 5, 1/2˝ bolts, nuts and lock washers, tighten to 60 (ft.lb) torque.
FIG 11-B with cutout in truck bed FIG 11-C.
FIG 11-E to the underside of the truck
FIG 11-F so bolts will pass through truck
FIG 12.
FIG 11-D,
WARNING
VEHICLE DAMAGE
• Mounting brackets must be bolted to frame. Welding will NOT pro-
vide the structural strength needed for towing and may void factory
warranty on vehicle.
11. The tops of the steel frame brackets must fit flush against the
underside of the truck bed and the inside of the steel frame brackets must fit flush against the truck frame for proper installation.
12. Position the frame brackets along each side of the truck frame
providing clearance to any crossmember, fuel line, electrical or
brake system. Drill 17/32˝ (.531˝) diameter holes through truck bed
and bed plate.
13. Secure the frame brackets to the truck bed and bed plate with SAE
Grade 5, 1/2˝ diameter bolts, nuts and lock washers (not supplied).
14. Drill 17/32˝ (.531˝) diameter holes through the lower leg of the
frame brackets and truck frame. The holes should be positioned in
the vertical center of the truck frame.
15. Secure frame brackets to the truck frame with SAE Grade 5, 1/2˝
dia. bolts, nuts and lock washers (not supplied).
16. Tighten all 1/2˝ bolts to 60 (ft.lb) torque.
17. Proceed with
INSTALLATION CHECK.
INSTALLATION CHECK
After finishing the installation, follow these steps:
1. Coat surface of hitch ball with wheel bearing grease to reduce wear
and corrosion.
2. Connect the trailer to the towing vehicle and adjust coupler drop
tube (see the coupler owner’s manual provided by the trailer manufacturer) to provide approximately 6˝ clearance between the bottom
of the trailer’s overhang and the top of the pickup box sides.
3. Check for proper clearance between trailer and both rear of cab,
and rear corner of truck bumper when making turns of up to 90°.
4. If trailer will be towed at this point; make sure coupler is securely
latched, connect wiring, safety chains, brake system breakaway
switch and any other appropriate connections and complete all system checks.
Your system is now ready for use.
OPERATION
FOLDING BALL
1. To raise hitch ball to towing position, open door and lift hitch ball
into vertical position.
2. Close door to lock the hitch ball in place for towing.
3. To fold hitch ball out of the way, door open, fold ball down, and reclose door.
SAFETY CHAINS - (
1. Lift up safety chain attachment link from top plate of folding ball unit.
2. Hook safety chain into attachment link.
BOUNCING LOOSE FROM ATTACHMENT LINK
IF APPLICABLE)
AFFIX HOOK SECURELY TO KEEP FROM
.
MAINTENANCE
1. Keep assembly free of dirt, mud and foreign matter.
2. Lubricate door hinge points with SAE 30 oil at least once every 3
months.
3. Lubricate hitch ball through standard grease fitting from underneath
the truck while the ball is in stowed position with a multipurpose
grease every 3 months.
4. Coat surface of hitch ball monthly with wheel bearing grease to prevent wear and corrosion.
5. Check for ball wear before each use. If hitch ball shows signs of
cracking, bending or flat spotting, it must be replaced. Do not tow
trailer with damaged or worn parts.
6. Check monthly for any looseness or excessive wear that may occur
from loose nuts and bolts. Assure that the bolts/nuts are properly
tightened.
WARNING
PERSONAL INJURY AND PROPERTY DAMAGE
• Replace ball if signs of cracking or flat spotting appear.
For problems or questions, contact your dealer, the trailer manufacturer,
or Atwood’s Consumer Service Department 574-264-2131.
3
Cross Section View
H-Frame Method
C
D
A
G
H
B
C
D
A
G
Bed Plate Method
Cross Section View
9
Bed Plate Dimensions
H-Frame Dimensions
8"
8"
width of truck frame
12
7
/
8
¨
12
7
/
8
¨
12
7
/
8
¨
8"
8"
14
1
/
2
¨
12
7
/
8
¨
12
10
H-Frame Assembly
118
E
F
E
F
44
¨
26¨
bottom view
H
H
E
E
B
A
H
G
G
A
C
A
B
C
B
2"- 6"
FRONT
FRONT
EQUAL
FRONT
123
46
57
3
5
4
6
7
A
center ball
8"
FORWARD
rear axle
centerline
12"
14"
7
1
/
2
¨
5
3
/
8
12
7
/
8
2
Installation Dimensions
CUT OUT
1
Folding
Hitch Ball
2
¨
- 6
¨
FOLDING BALL
2-6
¨
forward
rear axle
centerline
rear axle
12¨
14¨
FRONT
REAR
Cut Out (shaded area)
5-3/8" Centerline
Layout Dimension
8¨ Cut Out Dimension
2¨ Ref
7-1/2" Centerline
Layout Dimension
2¨ Ref
4
Atwood Hardware Systems & Components Limited Warranty
Atwood Mobile Products warrants to the original ownerr this product will
be free of defects in material and workmanship for a period of two years
from the date of purchase. Atwood’s liability hereunder is limited to the
replacement of product, repair of product or replacement of product
with a reconditioned product, at the discretion of the manufacturer. The
warranty is void if the product has been damaged by accident, unreasonable use, neglect, tampering or other causes not arising from
defects in material workmanship. The warranty extends to the original
consumer purchaser of the product only, and is subject to the following
conditions:
1. For two (2) year commencing with the date of purchase, Atwood will
replace or repair any Hardware System & Components that are found
to be defective by Atwood in material or workmanship.
2. In the event of a warranty claim, the Original Purchaser must contact
the Atwood Consumer Service Department, 1120 North Main St.,
Elkhart, IN 46514, Telephone: 574-264-2131 Fax: 574-206-9713.
Warranty claim service must be performed as approved by the
Atwood Consumer Service Department. Warranty replacement hardware systems and components or parts will be furnished freight prepaid. Labor cost to repair or replace will be
limited to the amount of the original purchase price of the systems and
components. The replaced warranty products or parts become the
property of Atwood Mobile Products and must be returned to the
Atwood Consumer Service Department freight prepaid, unless prior
arrangements have been agreed to.
3. This limited warranty is valid only when the product is applied,
installed, maintained and operated in accordance with this Atwood
Installation, Maintenance and Operating Manual. Any deviation from
these recommended specifications must be approved in writing by
Atwood.
4. Any implied warranties are limited to the duration of this limited warranty as stated above. Atwood does not assume responsibility for
consequential damage or loss, including loss of use of vehicle, loss
of time, inconvenience, expense for gasoline, telephone, travel, lodging, loss or damage to personal properties, or loss of revenues.
Some states do not allow limitations on how long an implied warranty lasts or limitations on consequential damages, so the above limitations may not apply to you. This limited warranty gives you specific
legal rights which may vary from state to state.
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