Here's a general outline. Specific steps might vary slightly depending on your exact model and modifications:
1. Preparation:
* Safety First: Work in a well-ventilated area away from ignition sources. Use proper safety glasses and gloves. Have a fire extinguisher nearby.
* Gather Tools: You'll need a variety of tools, including sockets (likely metric), wrenches, screwdrivers (Phillips and flathead are common), a fuel pump pliers (if the fuel lines are clamped), a fuel line disconnect tool (highly recommended), safety glasses, gloves, rags, and possibly a jack and jack stands to safely access the fuel tank. A siphon pump is helpful to remove remaining fuel from the tank.
* Drain the Fuel Tank: This is crucial. Siphon as much fuel as possible from the tank into a properly labeled and sealed container. Dispose of the fuel properly according to local regulations.
* Disconnect the Battery: Always disconnect the negative (-) battery terminal first.
2. Accessing the Fuel Tank:
* Locate the Fuel Tank: It's typically located under the vehicle, often near the rear axle.
* Lower the Tank (If Necessary): Depending on your CJ7's setup, you might need to lower the fuel tank to access the sending unit. This often involves loosening straps or bolts holding it in place. You may need a jack and jack stands to support the tank safely while it's partially lowered. Be extremely careful not to damage the fuel lines.
* Disconnect Fuel Lines: Carefully disconnect the fuel lines using the appropriate tool to prevent fuel spillage. Keep the lines clean and free from debris. Consider plugging the lines to avoid spillage.
3. Removing the Sending Unit:
* Locate the Sending Unit: It's typically located on top of the fuel tank, often with a retaining ring or nut holding it in place.
* Disconnect Electrical Connections: Disconnect the electrical connector from the sending unit.
* Remove the Retaining Ring or Nut: Carefully remove the retaining ring or nut that secures the sending unit to the fuel tank.
* Remove the Sending Unit: Gently pull the sending unit out of the fuel tank. It might be stuck due to corrosion or debris. Use caution to avoid damaging the tank's gasket.
4. Installing the New Sending Unit:
* Clean the Mounting Surface: Thoroughly clean the mounting surface on the fuel tank to ensure a good seal.
* Install New Gasket (if applicable): Install a new gasket on the tank if the old one is damaged or torn.
* Install the New Sending Unit: Carefully insert the new sending unit into the fuel tank, ensuring it's properly seated.
* Secure the Sending Unit: Replace the retaining ring or nut to secure the new sending unit.
* Reconnect Electrical Connections: Connect the electrical connector to the new sending unit.
5. Reassembly:
* Reconnect Fuel Lines: Carefully reconnect the fuel lines, ensuring they are securely attached and there are no leaks.
* Raise the Fuel Tank (If Necessary): Raise the fuel tank back to its original position and secure it properly.
* Reconnect the Battery: Reconnect the positive (+) battery terminal.
* Check for Leaks: Carefully inspect all connections for leaks.
6. Testing:
* Start the Engine: Start the Jeep and check the fuel gauge to make sure it's working correctly.
* Observe for Leaks: Check for any fuel leaks around the fuel lines and sending unit.
Important Considerations:
* Fuel Tank Safety: Always work in a safe environment, away from any ignition sources.
* Gaskets and Seals: Replace any damaged gaskets or seals to prevent leaks.
* Correct Part: Make absolutely sure you get the correct replacement sending unit for your 1985 Jeep CJ7.
* Professional Help: If you're uncomfortable performing this repair yourself, it's best to take it to a qualified mechanic.
This is a general guide. Consult a repair manual specific to your 1985 Jeep CJ7 for detailed instructions and diagrams. These manuals will often provide valuable insights specific to your vehicle's configuration. Improper installation could lead to fuel leaks and safety hazards. If unsure, seek professional help.
