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.
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HOMESERVICE MANUALSPONTIAC1987J2000/SUNBIRD L4-121 2.0LREPAIR AND DIAGNOSISSPECIFICATIONSMECHANICAL SPECIFICATIONSBRAKE ROTOR/DISC
1987 Pontiac J2000/Sunbird L4-121 2.0L
Brake Rotor/Disc
1987 Pontiac J2000/Sunbird L4-121 2.0LSECTION Brake Rotor/Disc
All rotors have a discard dimension cast into them. This is a wear dimension and not a refinish dimension. Any rotor which does not meet the specification should be replaced.
| (JA1) LIGHT DUTY (FRONTS) | (JA2/JA8) MEDIUM AND HEAVY DUTY (FRONTS) | REAR | |
| Rotor Diameter | 9.72 Inch (in) | 10.24 Inch (in) | 10.237 Inch (in) |
| Lateral Runout | 0.004 Inch (in) | 0.004 Inch (in) | 0.004 Inch (in) |
| Thickness Variation | 0.0005 Inch (in) | 0.0005 Inch (in) | 0.0005 Inch (in) |
| Rotor Thickness (Max) | 0.885 Inch (in) | 1.043 Inch (in) | 0.494 Inch (in) |
| Minimum Thickness after Refinish | 0.83 Inch (in) | 0.972 Inch (in) | 0.439 Inch (in) |
| Discard Thickness | 0.815 Inch (in) | 0.957 Inch (in) | 0.425 Inch (in) |
RENDER: 1.0x
NO RELATED
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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.