SERVICE CAMPAIGN
L SERIES TRUCKS HOOD SERVICE
GROUP: 0-GENERAL
CAMPAIGN NO: M0390
DATE: 12-7-2022

SUBJECT VEHICLES: Certain 2023 Model Year

L-Series hoods may need to have a fiberglass repair performed.
OVERVIEW
The subject vehicles may need to have a fiberglass repair
performed on the truck.
PARTS:
Part Name

Quantity

1.5 Ounce Fiberglass Mat

As needed

SMC Fiberglass Resin

As needed

SMC Fiberglass Resin Hardener

As needed

80 Grit Sand Paper

As needed

Tack Cloth

As needed

Mixing cup

As needed

2 inch Flat Chip Brush

As needed

1.5 inch Masking Tape

As needed

Loctite Power Grab Heavy Duty
Construction Adhesive (or similar)

As needed

Note: The Resin must be SMC (sheet molding compound). You
must also use the correct cream hardener for the resin. See
below for an example.

BEFORE YOU BEGIN:
• Read and understand all instructions and procedures
before you begin the work.
• Read and follow all NOTICES and WARNINGS set
forth in this publication. These alerts help to avoid
damage to components, serious personal injury, or
both.
• Park the vehicle on a flat, level and solid surface.
• Turn off the engine and remove the key from the
ignition switch.
• Always wear safety glasses or goggles to protect
• your eyes.
• Place wheel chocks in front of and behind all
wheels to prevent the vehicle from moving
VEHICLE PREPARATION:
1. Park the vehicle on a level and solid surface. Confirm the
engine is stopped, the starter switch is in the off (LOCK) position,
and the key is removed.

2. Apply the parking brake. Chock all of the wheels.

Notice: Inspect the paint on the hood to make sure there are
not any defects or damage.
REPAIR PROCEDURE:
WARNING: Never work under the hood unless the hood is
properly supported. Serious personal injury can occur.
1. Following the cab section of the Chassis Workshop Manual,
remove the hood from the vehicle and place the hood upsidedown.
Note: take appropriate steps to ensure that the paint on the hood
is not damaged while resting upside-down.
Use a padded blanket or cushion to protect the hood.

2. Remove the left and right hood hinge brackets and left and
right rubber baffles from inner grille area.

3. Relocate the wiring harness by removing the harness retainer
clips to allow the harness to lie on the top of the hood.

4. Remove the left and right hood support brackets.

WARNING: ALWAYS wear eye protection, a face mask, gloves
and protective clothing when grinding, drilling, and sanding
fiberglass, epoxy resin and adhesive materials. Fiberglass
materials may cause mouth, nose, throat, skin and eye irritation.
Epoxy resin and adhesive materials may cause skin irritation and
eye irritation.
5. Using 80 Grit sand paper, sand the left and right hinge mount
areas identified with the striped markings as seen below. You will
only sand to take the sheen off of the affected areas. It is not
necessary to remove a lot of material.
Notice: you will also sand on the metal bracket only in the areas
noted in the picture. It isn’t necessary to sand where the hinge
bracket bolts to the hood bracket.

WARNING: ALWAYS wear eye protection, a face mask, gloves
and protective clothing when grinding, drilling, and sanding
fiberglass, epoxy resin and adhesive materials. Fiberglass
materials may cause mouth, nose, throat, skin and eye irritation.
Epoxy resin and adhesive materials may cause skin irritation and
eye irritation.
6. Using 80 grit sand paper, sand around the hood support
bracket mount as identified with the striped markings in the
picture below.
Note: if there is any excessive adhesive from when the hood was
manufactured present at that joint, it will need to be sanded down
until smooth.

Clean all sanded areas by blowing off all dust and using a tack
cloth to remove all fine dust particles.

7. Use Loctite Power Grab heavy duty construction adhesive (or

similar) around the hood hinge mount bracket. Run a lite bead of
adhesive and smooth out to create a beveled edge where the
yellow lines indicate as shown below. Do not use an excessive
amount of adhesive.
Notice: This beveled edge is intended to reduce the possibility
for air to be trapped at the joint when the fiberglass is applied.

If necessary, use Loctite Power Grab heavy duty construction
adhesive (or similar) at the joint between the hood support
bracket mount and the hood.
Notice: If there isn’t a smooth transition between the two, use the
adhesive to create the beveled edge similar to when applied to
the hood hinge bracket.

8. Use masking tape to protect the hood paint around the hood
support bracket area.

9. Use paper to cover inside of the grille to protect the grille from
resin drips.

10. Use masking tape and paper to protect the front of the
hood/grille from any damage or resin drips.

11. Mark with a permanent pen all wire harness retaining clip
holes that will be covered with fiberglass. There are 4 holes to
mark on each side of the hood.

Apply fiberglass to hood support bracket mount
12. Prepare strips of fiberglass to be used for the left and right
side support bracket mount as identified below. The green area
will consist of strips of 30mm wide fiberglass and the blue area
will consist of strips of 50mm wide fiberglass. Make sure that the
strips are long enough to overlap whenever there is a change in
direction.

Mix resin with an appropriate amount of hardener and stir until
fully combined.
Apply a light coat of resin with the brush to the blue area of the
hood and lay the 30mm wide fiberglass over the joint. Apply resin
to the fiberglass matt until the fiberglass is saturated, with no dry
spots remaining and lying flat on all surfaces. Do not over apply
the resin. Pat at the fiberglass to work any air bubbles out from
under the fiberglass.

Notice: Make sure to keep the seam centered along the length of
the fiberglass strip.
Lay the 50mm wide fiberglass and repeat the process of applying
resin to the fiberglass until wet. Do not over apply the resin. Pat
the fiberglass to smooth it out and make sure there isn’t any air
bubbles under the fiberglass.
Notice: Make sure to keep the seam centered along the length of
the fiberglass strip.
Repeat this process on the other side.
Apply fiberglass to the hood hinge support bracket area
13. Prepare fiberglass sheets to be used. Use the below pictures
to cut out two sheets of fiberglass for each template provided.

14. Prior to applying the resin, lay the cut fiberglass sheet over
the hood hinge area so that you can mark where the bolt head is
so that it can be cut out. Also it may be necessary to make a few
cuts to allow the fiberglass to lay properly over the multiple
bends. Make your adjustments to the fiberglass prior to using the
resin.
Notice: Make sure the fiberglass doesn’t overhang the inner grille
area where the rubber baffles mount when making adjustments.

Notice: Do this for all three sizes of fiberglass sheet.
Notice: Pay attention to the area that the largest size sheet
covers as it will aid when you lay the light coat of resin prior to
laying the first sheet of fiberglass.

15. Mix resin with an appropriate amount of hardener and stir
until fully combined.
Apply a light coat of resin to the area that the largest layer will
cover. Apply the largest sheet of fiberglass and apply resin to the
fiberglass matte until the fiberglass is saturated, with no dry spots
remaining and lying flat on all surfaces. Do not over apply the
resin. Pat at the fiberglass to work any air bubbles out from
under the fiberglass.
Notice: do not apply the next layer until you are certain all air is
removed.

Repeat the process for each additional sheet of fiberglass.
Notice: The order of installation is Largest size first, medium size
second and smallest size last.
Repeat the process on the other side of the hood.
Allow the Fiberglass to set until there isn’t any tacky
feeling any more.

WARNING: ALWAYS wear eye protection, a face mask, gloves
and protective clothing when grinding, drilling, and sanding
fiberglass, epoxy resin and adhesive materials. Fiberglass
materials may cause mouth, nose, throat, skin and eye irritation.
Epoxy resin and adhesive materials may cause skin irritation and
eye irritation.
16. Use 80 grit sand paper to sand over the dried fiberglass to
knock down any high spots and loose glass. Do not sand to a
smooth surface. If any glass is hanging over the inner grille area
where the rubber baffles mount, remove with a die grinder and a
sanding wheel.
Drill out the holes that were marked earlier using a 5/16 inch size
drill bit.

Notice: If you are unable to see the location of the holes, shine a
flashlight from behind and you can then see the location of the
holes.
17. Use spray paint to paint over all of the new fiber glass. Use
paint that is similar in color to the underside of the hood. Allow
paint to dry.

18. Remove all tape and protective paper.
19. Reinstall the left and right hood hinge brackets.
20. Reinstall the left and right hood support brackets.

21. Reinstall the left and right rubber baffles from the inner grille
area.

22. Reinstall the wiring harness clips into their appropriate
location.
23. Reinstall the hood. For additional information, refer to the
cab section of the Chassis Workshop Manual.

FINAL INSPECTION:
1. To complete this procedure review and confirm the following:
•

Inspect the paint on the hood to make sure there wasn’t any
damage to the hood while performing this repair.

CLAIM APPLICATION
Reimbursable in accordance within the terms and policies of the
Hino limited warranties.
Hood Repair:
a)
b)
c)
d)
e)
f)

Campaign No: M0390
Labor Charge: 6.0 Hours
Warranty Code: 71221
Trouble code: 98
Operation code: 71250AOT
Original failed part: 9999999999