Mast Assembly (Sections)

Repair Information

Review all collision repair general practices and safety documentation and wear the appropriate PPE (Personal Protective Equipment) before beginning this procedure.
Properly mount the vehicle on a frame bench when performing this procedure.
Depending on the damage to this component, it may be possible to repair this component. Refer to Mast Assembly Repair Guidelines for more information.
The Mast Assembly is a single component, and if it cannot be repaired, it can be replaced as a single repair. Alternatively, instead of replacing the complete Mast Assembly, the rear section of the Mast Assembly can be replaced using the Cast Mast Rear Section service part and the backing plates described in the Parts List, and the instructions in Mast Assembly Section Descriptions.

Parts List


Quantity	Description	Image / Notes
For component replacement only: 1	ASY MAST CASTING (Mast Assembly)
For section repairs only: 1	TOP BACKING PLATE
For section repairs only: 1	TOP MIDDLE BACKING PLATE
For section repairs only: 1	BOTTOM MIDDLE BACKING PLATE
For section repairs only: 1	BOTTOM BACKING PLATE
For component replacement: 16 For section repairs: 13	High Strength Structural Rivet, 6.5 mm

When ordering parts, refer to the Parts Catalog and enter the VIN of the vehicle being repaired to find the correct parts (and the part numbers) for the vehicle. Alternatively, use the search function in the Parts Catalog to find a specific part for the vehicle.

Mast Assembly Section Descriptions


Mast Assembly Section Descriptions
Cut the service part just forward of the raised cut line to create the replacement component. Cut Line To remove the damaged component, cut on the raised cut line on the cast component. Cut Line Note If the Mast Assembly is damaged forward of the raised cut line, sectioninng is not allowed and the entire component must be replaced. Trim both the replacement component and the remaining portion of the component on the vehicle to fit. Note The maximum gap between new and existing components is 3 mm. On both the replacement component and the remaining portion of the component on the vehicle, sand any remaining portion of the raised cut line flush with the rest of the component to allow the backing plates to fit flush with the component. Prepare for installation. or High Strength Structural Rivets, 6.5 mm Apply structural adhesive to the mating surfaces on the vehicle and the new component or components. Note Fill any gaps with structural adhesive. Install the backing plates.

Repair Procedure

Remove the Rear Header Lower.
Remove the Rear Wall Upper Crossmember Glove.
Remove the original component.
or Factory Spot Welds
or Factory SPRs
Prepare for installation.
or High Strength Structural Rivets, 6.5 mm
Apply structural adhesive to the mating surfaces on the vehicle and the new component or components.
Install the new component or components.
Install the Rear Wall Upper Crossmember Glove.
Install the Rear Header Lower.
Install the fastener as indicated.
or High Strength Structural Rivets, 6.5 mm
Perform any necessary post-repair operations.