Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Standard Practices
The following rules apply, unless specified differently in the procedure:
FASTENERS
- Reuse standard fasteners.
- Replace fasteners with self-locking features.
- Examples of fastener self-locking coatings or mechanical locking (with the locking features highlighted yellow) are shown in the illustration.
- Replace fasteners with torque angle specifications (those tightened a specified number of degrees).
Examples of self-locking nuts and bolts
| Item | Part Number | Description |
|---|---|---|
| 1 | - | Completely coated self-locking bolt |
| 2 | - | Partially coated self-locking bolt |
| 3 | - | Self-locking bolt with a locking washer |
| 4 | - | Self-locking nut with a plastic locking insert |
| 5 | - | Self-locking nut with thread deformation (3 indentations) |
| 6 | - | Self-locking nut with thread deformation (to oval shape) |
| 7 | - | Self-locking nut with integrated locking ring |
THREAD FORMING FASTENERS
The following is a general description of best practices to be followed during handling of thread forming fasteners and mating components.
Manual Torque Application
Hand tools are required for installation of a thread forming fastener. Do NOT use power tools, as the possibility for over-torqueing or stripped threads exists. If a fastener is over-torqued, the joint can fail.
Hand Start Fasteners in Reverse
To avoid the possibility of cross-threading pre-existing threads during fastener replacement, begin by first hand-inserting the new fastener and rotating counter-clockwise. This reverse rotation allows for the location of existing fastener threads to ensure the fastener does not cross-thread upon thread re-engagement. Once the existing fastener threads are located, hand-start individual fasteners manually until finger tight.
Risks of Over-Torque
Consult the Service Information procedure when torqueing thread forming fasteners and follow torque specification as listed. Make sure the fastener is fully seated against the mating component with no gap during reassembly.
Corrosion
During fastener replacement, inspect both fastener and mating component for signs of rust or other corrosion. If corrosion is found, replace corroded components with new components.
Stripped Threads
If internal (mating component) threads or external (fastener) threads appear stripped or galled, replace both fastener and mating component. When tightening, if minimum torque is not reached, internal threads on mating component may have stripped. Remove the fastener to inspect and replace mating component if stripped threads are found.
Face Seals
When replacing fasteners, inspect mating component surface for debris, damage, disturbance, wear, or abrasion and replace any seals or gaskets if damage is found.
SEALS AND GASKETS
Replace seals and gaskets, unless specified differently in the procedure.
EXTERIOR TRIM PARTS
Replace exterior trim parts fastened with glue or adhesive tape, unless specified differently in the procedure.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.