Cast Rear Under Body (2–Piece) Repair Guidelines

Explains how to determine if the damaged cast Rear Under Body component can be repaired or if replacement is required.

The criteria to determine if a cast Rear Under Body component is repairable or if the Rear Under Body must be replaced are based on both the severity and the location of the damage. Use the images and information below to determine if the Rear Under Body component may be repaired or if replacement is required.

Note

Depending on the build date and location of manufacture, a Model Y vehicle might have a 1-piece Rear Under Body or a 2-piece Rear Under Body. Use the images in the sections below to identify damage to 2-piece Rear Under Body components. If the damaged vehicle has a 1-piece Rear Under Body, refer to the Cast Rear Under Body (1–Piece) Repair Guidelines.

The images below show different views of one side of the Rear Under Body, and contain highlighted areas (the images below use the LH portion of the Rear Under Body for reference, but repair areas on the RH Rear Under Body are similar). Compare the damaged area of the vehicle's Rear Under Body to the images below, then use the repair criteria corresponding to the color of the highlighted area to find the criteria to use to determine if the damaged area of the Rear Under Body can be repaired.


2-Piece Rear Under Body – Top View	2-Piece Rear Under Body – Bottom View
2-Piece Rear Under Body – Outside View	2-Piece Rear Under Body – Inside View

Based on the colors used in the images above, the allowed repairs are as follows:

Table 1. Allowed Repairs
Area Color	Allowed Repairs
Blue areas (tabs):	Tabs that are broken off entirely can be welded back into place. Tabs that are partially broken or cracked can be repaired by welding. Bent tabs can be straightened using cold methods. Note Do not use heat methods to straighten tabs.
Green areas:	Welding damage up to 50 mm is allowed. For damage more than 50 mm in length, contact Tesla Collision Repair for assistance. Bent webbing sections may be straightened using cold methods. Note Do not use heat methods to straighten webbing sections.
Yellow areas:	Welding damage up to 30 mm is allowed (a reinforcement plate is not required). Welding damage between 30 mm and 50 mm in length is allowed, but reinforcement plates (Tesla part number 1076938-E0-B) must also be installed. See Installing a Reinforcement Plate for more information. For damage more than 50 mm in length, contact Tesla Collision Repair for assistance. Bent webbing sections may be straightened using cold methods. Note Do not use heat methods to straighten webbing sections.
Orange areas:	Welding a crack up to 30 mm is allowed, but a reinforcement plate (Tesla part number 1076938-E0-B) must also be installed. See Installing a Reinforcement Plate for more information. For damage more than 30 mm in length, contact Tesla Collision Repair for assistance. Bent webbing sections may be straightened using cold methods. Note Do not use heat methods to straighten webbing sections.
Red areas:	None; if the Rear Under Body is damaged in these areas, contact Tesla Collision Repair for assistance.

Warning

When welding on the cast Rear Under Body, use only approved aluminum welding wire, as specified in Approved Gas Metal Arc (GMA) Welders and Welding Wire.

Installing a Reinforcement Plate

Reinforcement plates may be installed on the Rear Under Body only at the direction of the Tesla Collision Repair Support Team, or as specified in the Allowed Repairs tables (above). Reinforcement plates on the Rear Under Body are installed as follows:

Note

Reinforcement plates on the Rear Under Body are not installed by welding; Rear Under Body reinforcement plates are installed only with structural adhesive.

Straighten the area where the reinforcement plate will be installed using cold methods.
Note
Do not use heat methods to straighten webbing sections.
Cut a section of reinforcement plate to length.
Note
Reinforcement plates are placed on both sides of cracked or straightened webbing. Make sure that each reinforcement plate covers the maximum surface area around the repair area.
Trim and rework the reinforcement plate as necessary to snugly fit over the area to be reinforced, and allow for any adjoining panels.
Remove any contaminants from the mating surfaces on the repair area and the reinforcement plate by cleaning them with isopropyl alcohol (IPA) prior to applying structural adhesive.
Apply structural adhesive.
Fit the reinforcement plates into position and clamp them into place.
Wipe off excess structural adhesive.

Warning

Before performing any repair that requires fasteners to be installed through an installed reinforcement plate, contact Tesla Collision Repair for assistance. Because the reinforcement plate increases panel stack thickness, it may be necessary to change fasteners used in repairs performed after the reinforcement plate has been installed.