Safety First:
* Jack up the vehicle securely and use jack stands. Never work under a vehicle supported only by a jack.
* Engage the parking brake.
* Wear safety glasses.
* Use appropriate tools.
Tools You'll Likely Need:
* Jack and jack stands
* Lug wrench
* Wheel chocks
* Socket wrench set (metric)
* Hammer
* C-clamp (or rotor puller)
* Pry bar (may be needed)
* Brake cleaner
* Wire brush
* Penetrating lubricant (like PB Blaster)
Steps:
1. Remove the wheel: Loosen the lug nuts before jacking up the vehicle. Then, raise the vehicle, secure it with jack stands, and remove the wheel.
2. Remove the drum: The rotor is likely integrated into the backing plate (drum). You might need to gently tap the drum with a hammer to loosen it from the backing plate. Sometimes penetrating lubricant applied around the edge of the drum helps. *Be careful not to damage the brake shoes.* The drum might simply slide off after a few taps.
3. Remove the backing plate (sometimes): On some models, the backing plate needs to be partially or fully removed to access the rotor. This usually involves removing some bolts or clips holding it to the axle housing. Check your repair manual to see if this is necessary for your specific Jimmy.
4. Remove the rotor: Once the drum is off, you'll see the rotor (it's part of the drum assembly). If there are retaining clips or bolts holding the rotor to the wheel studs, remove them. If the rotor is stuck, you might need to use a C-clamp or a rotor puller to carefully pull it off. Avoid damaging the wheel studs. *A gentle pry bar can help, but be cautious not to bend anything.*
5. Clean everything: Once the rotor is removed, thoroughly clean the wheel studs, backing plate, and the rotor mounting surface with a wire brush and brake cleaner.
6. Install the new rotor (in reverse order): Install the new rotor, making sure it slides on easily. If it's tight, consult your repair manual, as there may be specific instructions for the installation process. Reinstall the drum and backing plate if they were removed.
7. Reassemble: Reinstall the wheel and tighten the lug nuts to the manufacturer's specified torque. Lower the vehicle carefully.
8. Bleed the brakes: After replacing rotors, it's crucial to bleed the brakes to remove any air that might have gotten into the system during the process.
Important Considerations:
* Drum-in-rotor assemblies can be tricky. If you're not comfortable working on brakes, it's best to have a qualified mechanic do the job. Improperly installed brakes can be dangerous.
* Check your repair manual: This is essential for specific torque specifications and removal procedures. Different years and models might have slight variations.
* Brake parts can be dangerous if mishandled: Take appropriate precautions.
This is a general guide. Always refer to a repair manual specific to your 1998 GMC Jimmy for detailed instructions and safety precautions. If you are unsure about any step, consult a professional mechanic.
