Hummer H1 (2006+). Manual - part 287

10-10 Body

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Figure 10-1: Riveting Patterns

Joint Design

Loads are applied through a joint to fasteners that hold it together. These loads are applied to fasteners in the form of shear
loads or tension loads. If the load is perpendicular to the axis of the fasteners, the fasteners are loaded in the shear. The
fasteners are loaded in the tension when the load is along the axis of the fastener, causing a pull on each end of the fastener.

Rivets are designed to be loaded in a shear. Do not create any new joints during the repairs which cause the rivets to be used in
a tension application. The bolts should be used for tension applications or a substituted for rivets in very high shear load
applications (Figures 10-2 and 10-3).

Figure 10-2: Rivet Loads in Shear

Figure 10-3: Bolts Replacing Rivets

DOUBLE ROW RIVETING PATTERN

TRIPLE OR MULTIPLE ROW RIVETING PATTERN

D = DIAMETER

OF RIVET

(PREFERABLY ABOUT

3X THICKNESS OF

THICKER SHEET)

RIVET

RIVETS

S10-109

BOLT

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Body 10-11

Repair Parts

Paint the repair parts or the patches with epoxy primer before installation.

Apply a sealing compound to the mating surfaces to prevent corrosion.

Install the part or the patch.

Paint the repaired area with epoxy primer.

Paint the repaired area with the polyurethane as required.

Repair of Negligible Damage

Negligible cracks are repaired by drilling a small hole at each end of the crack to stop the crack propagation. This is called
stop-drilling. Table 7 gives the proper drill sizes for the stop-drilling cracks.

Negligible holes are repaired by rounding and smoothing the edges of the holes to alleviate the stress risers caused by sharp
notches.

CAUTION: Never use heat to reform parts. The part strength is greatly reduced.

Small dents and distorted areas may be repaired by bending or hammering as long as the operation does not cause the materials
to crack or tear. Sharp bends should not be attempted.

Repair by Patching

Most body panel damage that exceeds the limits of negligible damage may be repaired by patching. This procedure involves re-
moval of damaged area and application of a patch to cover the area. The damaged area is prepared by rounding or smoothing of all
corners and edges to ensure cracks will not spread into undamaged areas (Figure 10-4). In case of a large crack, it may be desirable
to stop-drill the crack rather than cut out a portion of the panel or structural member. Repair is completed by applying a large over-
lapping patch over the damaged area (Figure 10-5). The overlap must be sufficient to allow the observance of proper rivet edge
distance (.25 in. or 6.4 mm). Large areas of damage are best repaired by attaching patch with multiple rows of rivets (Figure 10-6).

Figure 10-4: Patching

Table 7: Stop-Drill Sizes for Negligible Cracks

SHEET THICKNESS

MINIMUM STOP DRILL BIT SIZE NO.

0-0.032 in. (0-081 mm)
0.033 in. (0.84 mm) and thicker

40
30

PATCH

DAMAGED AREA

10-12 Body

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Figure 10-5: Patching Cracked Areas

Figure 10-6: Proper Rivet Distance

Repair by Insertion

For damage that is large or more severe in nature than a crack or hole, it is often desirable to remove the damaged area, insert a
piece of material into the removed area and reinforce with a doubler. This is a termed repair by insertion. This method of repair is
typically stronger and stiffer than an added patch (Figures 10-7 10-8, 10-9, and 10-10).

Figure 10-7: Reinforcing Damaged Area

PANEL

PATCH

CRACK

PROPER RIVET

EDGE DISTANCE

.25 In. (6.4 mm)

DOUBLER

DAMAGED AREA

MATERIAL

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Body 10-13

Figure 10-8: Doubler

Figure 10-9: Damaged Body Area

Figure 10-10: Side view of Doubler

DOUBLER

MATERIAL

DAMAGED AREA

MATERIAL

DOUBLER

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