Replacing The Fuel Pump In Your Volvo 740: Step-By-Step Guide

Replacing the fuel pump on a Volvo 740 can be a complex task, but with the right tools and knowledge, it is possible to do it yourself. The fuel pump is located in the fuel tank, and there are two methods to replace it: dropping the gas tank or removing a plate in the trunk. The latter is generally considered the easier option. Before beginning any work, it is important to consult a trusted mechanic or a professional Volvo service for advice specific to your model and year. When replacing the fuel pump, it is also recommended to replace the top gasket, hose clamps, and the fuel pump hose. Additionally, it is important to be cautious when working with electrical wires and fuel lines to avoid damage and leaks.

Disconnect the battery and remove the body panel covering the fuel sender unit

To replace the fuel pump on a Volvo 740, you'll first need to disconnect the battery negative. Place a foam pad or rug on the bottom of the trunk for comfort as you lie there.

Next, you'll need to remove the body panel covering the fuel sender unit top. If you have a sedan, first remove the left side and center carpeted covers. For the wagon hatch, you'll need to remove the forward cargo cover. Remove the rear cover above the spare, then unscrew the front cover. You don't need to remove the vertical plastic trim piece – just push it to access the front screws on the hatch.

Now that you've removed the access cover, you can make more room by disconnecting the filler vent line and filler hose. Be careful not to damage the electrical wires.

At this point, you'll be able to access the Volvo quick disconnect fitting on the fuel outlet line. Grip the outer sleeve and push the outer plastic cylindrical sleeve towards the top of the fuel tank send unit. Keep the sleeve pushed forward and push the entire fitting towards the top of the tank. Press on the top of the quick-release fitting to release it from the send unit's steel tube. Pull the quick-release fitting from the steel tube. You may need a little penetrating oil to free up the inner o-rings from any rust on the tube.

Remove the access cover and disconnect the filler hose

To remove the access cover and disconnect the filler hose on a Volvo 740, follow these steps:

First, make sure you have the necessary tools and parts. You will need an LED headlamp, a length of strong string, some Vaseline or light grease, and potentially some new clamps and hoses, depending on the condition of the existing parts. It is also recommended to have a foam pad or rug to lie on while working.

Next, disconnect the battery negative terminal and place your foam pad or rug on the bottom of the trunk for comfort.

Now, you can begin removing the body panels to access the fuel sender unit. For a sedan, remove the left side and center carpeted covers. For a wagon, remove the rear cover above the spare tire, then unscrew the front cover. You don't need to remove the vertical plastic trim piece; simply push it to access the front screws on the hatch.

After removing the access cover, make more room by first disconnecting the filler vent line. Be careful not to damage the electrical wires.

Now, you can disconnect the filler hose. To do this, follow the steps below:

• Grip the outer sleeve of the Volvo quick disconnect fitting on the fuel outlet line and push it towards the top of the fuel tank sender unit.
• Keep the sleeve pushed forward and push the entire fitting towards the top of the tank.
• Press on the top of the quick-release fitting to release it from the sender unit's steel tube.
• Pull the quick-release fitting from the steel tube. You may need a little penetrating oil to free up the inner o-rings from rust.

If you break the quick disconnect, the part number is "fuel feed line" Volvo p/n 9142814, which includes the connector, plastic line, and metal line to the car.

Once the filler hose is disconnected, you can proceed with the fuel pump replacement, following the instructions provided by the manufacturer or a trusted source.

Remove the fuel sender unit

To remove the fuel sender unit from your Volvo 740, you will need to follow these steps:

Firstly, locate the fuel sender unit, which is found in the trunk or tailgate area. Remove any carpet or panels that are covering the access point. For a Volvo 740 wagon, this may involve folding down the back seat and removing the floor panel behind it to access the spare tire compartment. Once you have located the access panel, remove it by unscrewing the hex head screws and carefully prying it off with a putty knife.

Next, you will need to disconnect the electrical wiring from the fuel sender unit. Be careful not to damage the wires. You may need to cut zip ties holding the wires in place and fish the wiring harness out through a grommet hole near the fuel sender unit.

Once the electrical connections have been disconnected, you can begin to remove the fuel lines and hoses. Be sure to have a container ready to catch any fuel spillage. Carefully disconnect the filler hose and the fuel outlet line, also known as the quick-release fitting. To disconnect the quick-release fitting, grip the outer plastic sleeve and push it towards the top of the fuel tank. Keep the sleeve pushed forward while pushing the entire fitting towards the top of the tank. Press on the top of the quick-release fitting to release it from the steel tube. You may need to use penetrating oil to free up the inner o-rings from rust.

After the fuel lines have been disconnected, you can now remove the fuel sender unit itself. Gently tap around the plastic lock ring with a screwdriver or a piece of wood to loosen it. Do not use excessive force to avoid cracking the plastic. Once the lock ring has been loosened, carefully lift and remove the fuel sender unit from the fuel tank. You may need to wiggle it slightly to free it from the tank.

With the fuel sender unit removed, you can now inspect it for any signs of damage or corrosion. If you are replacing the fuel pump, you will need to disassemble the fuel sender unit further to access the pump. This process may vary depending on the specific model and year of your Volvo 740, so be sure to consult a repair manual or seek guidance from a Volvo specialist if needed.

Check for corrosion and replace the gasket if necessary

Corrosion is a common issue with the fuel pump on Volvo 740s. If you have the metal sending unit top, it will invariably be corroded. De-rust it and treat it with POR-15 to prevent future rusting. If your sending unit top is plastic, the metal fuel lines going through it will be rusted. Remove as much rust as you can, sand the affected areas smooth, and treat the exposed areas with POR-15. Rust can creep down between the metal and plastic, causing the plastic sending unit top to swell and crack. De-rust to the extent that you can and reinforce the joint between the tube and the plastic sender top with epoxy if necessary.

Now is a good time to replace the fuel tank gasket if necessary. Lubricate the gasket surfaces and the tank opening's inner surface with Vaseline. Do NOT lubricate the outer screw threads on the tank outlet or the plastic nut, so as not to overtighten it on reinstallation.

Reassemble and test for leaks

Once you have finished replacing the fuel pump, it is important to reassemble the various components and test for leaks.

First, grease the fuel hose clamps to prevent corrosion. Then, reassemble the fuel hose connections and attach the electrical connector. Push the electrical connector into the wiring holder to the left of the hatch opening, under the deck, and use zip ties to secure it to the fill tube.

Next, replace the tank access cover. Start the car and pressurize the fuel system, then shut it down after a minute or so. After fifteen minutes, carefully check for leaks. If no leaks are detected, reinstall the trunk fittings.

If you are having trouble getting the quick-release fitting to work, you may need to install a 1.5-inch long rubber fuel line hose and a 90-degree brass hose elbow from a plumbing supply store. To attach the brass elbow to the steel tube, you will need to slide a 1.5-inch long length of fuel hose over the steel tube. Use three screw-operated hose clamps to secure the hose, with two on the hose section that has been slid over the steel tube and one on the other end. Push the brass elbow into the rubber hose and secure it with another hose clamp.

Finally, cut a length of fuel hose to connect the brass elbow to the rubber fuel hose that runs towards the engine. You will need a brass straight hose splice and five more hose clamps. Once all the clamps are tightened, you should have a vapour-tight connection.

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