Frame Repairs

FRAME REPAIRS

Special Tool(s):

Special Tool(s)

Material:

Material

Welding Precautions

WARNING:
- If equipped with fire suppression system, depower the system. For important safety warnings and procedures, refer to Fire Suppression System.
- On vehicles equipped with air suspension, the electrical power supply to the air suspension system must be shut off prior to lifting the vehicle. This can be accomplished by disconnecting the battery or turning off the air suspension service switch located in the luggage compartment on the LH side. Failure to do so may result in unexpected inflation or deflation of the air springs, which may result in shifting of the vehicle during these operations.

NOTE: Corrosion protection needs to be restored whenever it is necessary to sand or grind through painted surfaces or E-coat, or when bare metal repairs are made.

1. If welding must be done on a frame, make sure the following requirements are met:
- If the frame is attached to the vehicle, the battery ground cable must be disconnected before using any electrical welding equipment.
- Do not use gas welding equipment.
- Use a temperature-indicating crayon to make sure that the temperature does not exceed 750 °C (1,400 °F).
- Install new spot-welded components by spot welding where possible. If spot welding is not possible, use puddle welding.

2. WARNING: If equipped with fire suppression system, repower the system. For important safety warnings and procedures, refer to Fire Suppression System.

If equipped with fire suppression system, repower the system.

3. Reactivate the air suspension system (if equipped).

Frame Straightening

WARNING:
- Straightening of front frame rail convolute is prohibited. Failure to follow these instructions may result in personal injury.
- On vehicles equipped with air suspension, the electrical power supply to the air suspension system must be shut off prior to lifting the vehicle. This can be accomplished by disconnecting the battery or turning off the air suspension service switch located in the luggage compartment on the LH side. Failure to do so may result in unexpected inflation or deflation of the air springs, which may result in shifting of the vehicle during these operations.

CAUTION: Straightening of severely bent or kinked frame components is prohibited. However, before removing these components, restore dimensionally to a pre-collision condition.

NOTE: Whenever factory E-coat has been removed by sanding, grinding or weld burn-off, the coating must be restored.

1. WARNING: If equipped with fire suppression system, depower the system. For important safety warnings and procedures refer to Fire Suppression System.

If heat is needed to straighten a frame member, keep the temperature below 650 °C (1,200 °F) (a dull red glow). A temperature sensitive thermal melt crayon should be used to monitor heat buildup.
- Heat should be kept to a minimum area so that the hardness of the metal will not be affected.
- Straightening should only be attempted on frames that fail to meet specifications, or where damage is apparent.
- Straightening should be limited to parts which are not severely bent.
- Reposition or shield any fuel lines, brake lines or wiring harnesses or components in heated area.

2. WARNING: If equipped with fire suppression system, repower the system. For important safety warnings and procedures refer to Fire Suppression System.

If equipped with fire suppression system, repower the system.

3. Reactivate the air suspension system (if equipped).

Underbody Misalignment Check

WARNING: If equipped with fire suppression system, refer to Fire Suppression System for Important Safety Warnings.

NOTE: Underbody misalignment can be the result of damage or loose frame components. It can affect front and rear wheel alignment and cause incorrect operation and abnormal wear of tires and chassis parts.

1. Inspect the frame for damage and loose parts before checking the frame alignment.
- Inspect all cross members for cracks, twists or bends.
- Inspect all of the welded connections for cracks.
- Check all of the support brackets for looseness.