Here's a general outline. Specifics may vary slightly depending on the exact engine in your truck (e.g., 4.3L, 5.0L, 5.7L, 6.2L). Consult a repair manual specific to your truck's year, make, model, and engine for detailed diagrams and torque specifications.
1. Preparation:
* Gather Tools: You'll need various wrenches (metric and possibly SAE depending on your truck), sockets, a power steering pump puller (highly recommended), a drain pan, rags, and possibly a pry bar.
* Fluid Drainage: Place the drain pan under the power steering pump. Locate the power steering fluid reservoir and carefully remove the cap. There's usually a fitting at the bottom of the pump to drain the fluid. Loosen it slowly to avoid a sudden gush of fluid. Allow the fluid to drain completely. Dispose of the fluid properly according to local regulations.
* Disconnect Battery: Disconnect the negative battery terminal.
2. Disconnecting Components:
* Pressure Line: Locate the high-pressure power steering line connected to the pump. This line will likely have a fitting that needs to be loosened with a wrench. Be prepared for fluid leakage, even after draining. Use rags to absorb any spillage.
* Return Line: Locate the low-pressure return line. This is typically easier to disconnect than the high-pressure line.
* Electrical Connector: There might be an electrical connector attached to the pump for the power steering pressure switch. Disconnect this carefully.
* Belt: Remove the serpentine belt (or the individual belt if it's not a serpentine system). Consult your repair manual for the correct procedure; you may need to loosen the alternator or other components to provide belt slack.
3. Removing the Pump:
* Pump Mounting Bolts: Locate the bolts securing the power steering pump to the engine block. These are typically located on the side of the pump. Unscrew these bolts.
* Pump Removal: This is where the pump puller comes in handy. A pump puller is designed to safely remove the pump without damaging the engine block. Position the puller according to its instructions and carefully pull the pump. If you don't have a puller, you may be able to carefully pry the pump loose, but this is riskier and can damage the pump or engine. Proceed with extreme caution.
4. Installation (Reverse Procedure):
Once the old pump is removed, installation is the reverse of removal. Be sure to use new gaskets and seals as needed to prevent leaks. After installation, refill the power steering fluid reservoir to the appropriate level, following the instructions in your vehicle's owner's manual. Bleed the power steering system to remove air bubbles. Reconnect the battery.
Important Considerations:
* Repair Manual: A repair manual specific to your 1991 Chevrolet Silverado is invaluable. It will provide detailed instructions, diagrams, torque specifications, and other crucial information.
* Safety: Always use appropriate safety precautions, including eye protection and gloves. Power steering fluid is harmful to the skin and eyes.
* Professional Help: If you are uncomfortable performing this repair yourself, it's best to take your truck to a qualified mechanic. Improper removal or installation can lead to damage to your vehicle or injury.
This information is for guidance only. Always consult a repair manual specific to your vehicle before attempting any repairs. Incorrect procedures can result in damage to your vehicle or personal injury.
