1. The Pulley Itself is Damaged:
* Bent or cracked pulley: Replace the pulley. This is common if something strikes it or if it's been subjected to significant stress.
* Worn pulley: While less common, extreme wear can lead to slippage. Replacement is the solution.
2. The Pulley is Loose or Wobbly:
* Loose pulley bolt: Tighten the bolt securing the pulley to the A/C compressor. Use the correct torque specification found in your Cadillac's repair manual. A loose bolt can cause the pulley to wobble and damage the belt.
* Worn compressor shaft bearing: This is a more serious problem. The bearing inside the compressor is worn, causing the pulley to wobble. You'll likely need to replace the entire A/C compressor. This is a major repair.
* Worn or damaged compressor clutch: The compressor clutch is what engages and disengages the compressor. If damaged, it can cause the pulley to wobble or not turn correctly. This will also likely require compressor replacement.
3. The Serpentine Belt is Slipping:
* Worn serpentine belt: The problem might not be the pulley at all. A worn, glazed, or cracked serpentine belt will slip on a perfectly good pulley. Replace the belt.
* Improper belt tension: The belt tensioner might not be providing enough tension. This often requires adjustments or replacement of the tensioner.
Repair Process (Assuming Pulley Replacement):
1. Disconnect the battery: This is crucial for safety.
2. Consult a repair manual: A Haynes or Chilton manual specific to your 1990 Cadillac Fleetwood is essential. It will show you exactly how the A/C system is arranged, how to access the pulley, and the correct torque specifications for all the bolts.
3. Access the pulley: This will involve removing components depending on your car's specific design. Expect to possibly remove the serpentine belt and maybe some other components to get to the pulley.
4. Remove the old pulley: Carefully remove the pulley bolt. Use the correct tools to avoid damaging the pulley or the compressor shaft.
5. Install the new pulley: Carefully install the new pulley and tighten the bolt to the specified torque.
6. Reinstall components: Put everything back together in reverse order of removal.
7. Reconnect the battery:
8. Check the belt tension and alignment.
9. Recharge the A/C system: This is crucial. If the system is low on refrigerant, the compressor may not work correctly, even with a new pulley. A professional A/C recharge is recommended.
Important Considerations:
* Safety: Working on an A/C system involves refrigerants that can be dangerous. If you're not comfortable working on this, take it to a qualified mechanic.
* Tools: You'll need the appropriate tools, including a socket wrench, possibly a pulley puller, and torque wrench.
* Refrigerant: Discharging refrigerant into the atmosphere is illegal and harmful to the environment. If you're replacing the compressor, you'll need to recover the refrigerant properly.
Replacing the A/C compressor is a much more complex job and should be handled by someone experienced in automotive A/C systems. If you suspect a problem with the compressor itself, don't attempt the repair yourself unless you have the necessary expertise and tools. A professional mechanic is recommended for this level of repair.
