atwood Folding Hitch Ball User Manual
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
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