ACRP Workbook Chapter 18: Structural Component Replacement

The first step in structural replacement is ___.

A. Fit up

B. Disassembly

C. Planning

D. Straightening

B. Disassembly

What happens during disassembly?

Bolted panels are removed to allow access to underlying structural parts

List three ways to open a door that is smashed shut.

Cut, pull, pry

True or false: All structural components should be aligned before damaged structural parts are removed.

True

True or false: Measuring should not be done before the vehicle is straightened.

False

Even though the damaged parts will be removed for replacement, they must be ___ first.

Straightened

True or false: You should be careful to not overheat damaged panels that will be replaced.

True

___ is removing and replacing only the damaged portion of a structural panel.

Sectioning

What is the greatest concern when sectioning?

Maintaining the vehicle's structural integrity

What are a unibody vehicle's structural components designed to do?

Protect the vehicle's occupants during a crash

True or false: In a collision, the sectioned panel must crush in the same way as an original panel.

True

True or false: Reinforcements made of ultra high-strength steel can be sectioned.

False

Which of the following are not commonly sectioned?

A. Fenders

B. Center pillars

C. Rear frame rails

D. A-pillars

A. Fenders

True or false: For sectioning to work, the damaged frame must be cut off first.

False

What should be done if there are no sectioning instructions available?

The entire panel must be replaced

True or false: All manufacturers allow sectioning of structural parts.

False

Before a panel is sectioned or replaced, the location of ___ must be determined before the panel can be removed.

Spot welds

How do you remove plug welds from a previous repair?

Center punch the weld and drill a pilot hole at the punch mark then drill out the weld with a spot weld cutter bit

True or false: When removing welds, grind on the weld only, not the surrounding metal.

True

Never grind away metal from the ___ panel.

Bottom

What is the proper hole size for a plug weld?

A. 1/9"

B. 3/16"

C. 1/8"

D. 5/16"

D. 5/16"

Good welding requires clean, ___ metal surfaces.

Bare

True or false: Weld-through primer should be applied to bare metal in the weld area after joining the panels together.

False

At minimum, how large should the gap between a weld and foam be?

A. 1/4"

B. 1/2"

C. 1"

D. 2"

D. 2"

Which of the following is not a part of fit up?

A. Measuring

B. Welding

C. Alignment

D. Positioning

B. Welding

If you do not have a 3D measuring system, how can you verify that structural panels are properly positioned before welding?

Temporarily install the important parts and check for fit

True or false: Laminated steel cannot be MIG welded and its components are joined by adhesives and rivets.

True

Replacement structural panels are installed with ___ or continuous welds if a MIG welder is used.

Plug welds

A(n) __ is a short but continuous bead about 3/4" long.

Stitch

All of the following are examples of structural joints and welds except:

A. Lap/spot

B. Offset butt/stitch

C. Pinch/plug

D. Lap/stitch

C. Pinch/plug

Which joint/weld is used to section a hydroformed aluminum full frame?

A. Offset lap/plug and continuous

B. Offset butt/stitch

C. Lap/spot

D. Butt/plug

A. Offset lap/plug and continuous

True or false: The butt joint with insert has a butt weld gap equal to two times the thickness of the panel.

False

What type of welding is recommended on an aluminum frame?

A. Pulse MIG

B. Oxyacetylene

C. STRSW

D. TIG

A. Pulse MIG

What size of rivets is used to bond laminated steel?

A. 3mm

B. 6mm

C. 9mm

D. 12mm

C. 9mm

True or false: After welding, any exposed weld-through primer should be removed.

True

How many coats of epoxy primer are applied to treated weld areas?

A. Two

B. Three

C. Four

D. Five

A. Two

____ foam is flexible enough that it will not change the shape of a panel if too much is applied.

Low density

Pumping too much ___ foam into the cavity may create over-expansion problems and even cause welded panels to separate.

High density

Replacement parts can be new or ___.

Salvaged

If a cutting torch is used on the metal at the salvage yard, at least __ of additional material around the cut should be removed before the part is used.

2"

True or false: If two or more pieces of a front section are welded together, they should be installed as a unit.

True

Name parts of the side section.

Upper and lower frame rails, front shock tower, A-pillar, rocket panel, center panel, quarter panel, rear shock tower, rear frame rail

The ___ of a repaired unibody vehicle is dependent on all the relatively thin structural panels retaining their designed strength.

Structural integrity

True or false: The rivets of a replaced radiator support must be drilled out with a drill bit that is smaller in diameter than the center hole in the rivet.

False

True or false: If the radiator support is supplied in individual pieces, only the damaged portions need to be replaced.

True

When replacing a radiator, what happens to spot welds that impede the removal of damage panels?

Located and drilled out

True or false: An apron adds greatly to the structural strength of the vehicle.

False

True or false: Aprons should always be replaced entirely and never sectioned.

True

When replacing a radiator, apply weld-through ___ to the bare metal surfaces that will be welded.

Primer

The position of the shock tower will determine ___ geometry.

Steering

True or false: Shock towers should always be replaced entirely and never sectioned.

True

List the parts that make up a left or right 3/4 front.

Shock tower, radiator support, apron, lower frame rail, and upper frame rail

Begin upper frame rail replacement by removing the ___, fender, and other outer parts as needed.

Hood

True or false: If a used upper frame rail is installed, it is usually not part of an assembly.

False

Lower front frame rails can span the distance from the radiator support to a point under the ___.

Passenger compartment

If the entire lower frame rail will be replaced, remove the ___.

Drivetrain

Damaged advanced high-strength steel cannot be repaired or ___.

Sectioned

The A-pillar is part of the ___ and is one of the strongest part of a unibody vehicle.

Cowl

All components of an A-pillar are spot welded and continuously welded together in a(n) ___.

Lap joint

If the splice in an A-pillar replacement is made between the door hinge mounts or under the lower hinge mount, the ___ is not involved in the replacement.

Windshield

The outer rocker panel may be part of a door opening or ___.

Uniside

When the rocker panel is damaged, the __ is often damaged as well.

Center pillar

To begin rocker panel replacement, remove the __.

Doors

If both the inner and outer panels of a center pillar need replacement, a(n) ___ joint is recommended.

Offset butt

Begin center pillar replacement by removing the __ trim from the pillar.

Interior

The rear frame rail is sometimes called a(n) ___.

Hat channel

True or false: Damaged trunk floors are often difficult to straighten.

True

True or false: One manufacturer recommends to start removal of a cast-aluminum wheelhouse by grinding out spot welds holding the upper extension to the cowl.

False

What temperature does one manufacturer recommend the adhesive holding the wheelhouse to the lower frame rail attachment be heated to with a heat gun for removal?

A. 100*

B. 200*

C. 300*

D. 400*

D. 400*

Two technicians are discussing a manufacturer's recommendations for the replacement of a cast-aluminum wheelhouse. Technician A says that the wheelhouse should be removed from the lower frame rail after being attached if it needs further adjustment. Technician B says to slide the wheelhouse without separating it to adjust the wheelhouse assembly after installation. Who is right?

A. Technician A

B. Technician B

C. Both A and B

D. Neither A nor B

B. Technician B

True or false: Damaged cross members can be left in place during frame straightening.

True

True or false: Any full-frame damage outside the sectioning area must be cut before it is straightened.

False