August 2026

1980 MGB Fuel Pump Location: Complete Guide to Finding, Diagnosing, and Replacing Your Pump

If you own a 1980 MGB and need to find the fuel pump, here is the bottom line: the fuel pump is located inside the trunk (boot) on the right-hand side, mounted behind a protective black metal box near the spare wheel and battery box. This is a major improvement over earlier chrome bumper models, which had the pump mounted underneath the car where it was exposed to road debris and corrosion. On your 1980 rubber bumper model, the electrical end of the SU fuel pump actually protrudes through the rear bulkhead into the trunk, making it much easier to access for diagnosis and service.

How to Access the Fuel Pump

Accessing the fuel pump on your 1980 MGB is a straightforward process that you can do with basic tools. Here is the step-by-step procedure:

Open the trunk lid and remove the spare wheel.
Look behind where the spare wheel was mounted. You will see a black metal box (the pump guard) attached to the rear bulkhead.
Remove the screws that hold this protective metal cover in place.
Once the cover is removed, you will see the top of the SU fuel pump with its electrical connections.

The pump itself is mounted with the electrical end protruding through the bulkhead, while the fuel line connections and the main pump body remain underneath the car, behind the rear axle. This design means you can perform many diagnostic checks and even clean the points from inside the trunk without ever crawling under the vehicle.

Common Signs of a Failing Fuel Pump

Before you start replacing parts, it helps to know what symptoms point to a failing pump. The most common signs include:

No ticking sound: When you turn the ignition key to the "on" position, you should hear the pump tick for a few seconds as it primes the carburetor float chambers. If you hear nothing, the pump may be dead or not getting power.
Engine dies unexpectedly: The car runs fine for a while, then suddenly stalls, especially under load or when accelerating.
Hard starting after sitting: If the car has been parked for a week or more, it may be difficult to start because the fuel lines have drained and the pump is too weak to refill them quickly.
Continuous rapid ticking: If the pump ticks constantly and rapidly, this often indicates an air leak in the fuel line or a failing diaphragm.

The "Whack-a-Pump" Trick

There is a well-known trick among MGB owners that can get you home if your pump stops working. This is the "whack-a-pump" method. Simply give the body of the pump a few firm taps with the handle of a screwdriver or a small hammer. This can free up stuck internal contact points and get the pump ticking again temporarily. On the 1980 model, you can access the pump from inside the trunk, so you do not even need to get under the car. If this trick works, plan on replacing the pump soon, as it is only a temporary fix.

Cleaning the Pump Points

If the pump is ticking but seems weak or slow, the internal contact points may just need cleaning. Here is how to do it:

Remove the black metal cover in the trunk to expose the top of the pump.
Disconnect the white electrical wire.
Undo the 2BA nut that holds the terminal and the plastic top cover.
Remove the plastic cover and any sticky tape sealing it.
Inside, you will find the contact points. Slide an emery board (or fine sandpaper) between the points and pull it back and forth a few times to clean them.
Reassemble everything in reverse order.

This simple cleaning can often restore proper pump operation for months or even years.

Replacing the Fuel Pump

If cleaning the points does not work, or if the pump has completely failed, replacement is the next step. For a 1980 MGB, the process is easier than on earlier models because the electrical connections are in the trunk. Here is a simplified overview of the process:

Disconnect the battery.
From inside the trunk, disconnect the electrical wire and loosen the worm drive clip that holds the pump in its rubber mounting.
From underneath the car, disconnect the fuel inlet and outlet pipes and the breather pipe.
Pull the old pump out through the rubber mounting.
Slide the new pump into the rubber mounting, ensuring the inlet and outlet ports face upward at a 45-degree angle.
Reconnect the fuel lines and breather pipe from underneath.
Back in the trunk, tighten the worm drive clip and reconnect the electrical wire.
Reconnect the battery and test for proper operation.

Many owners find that replacing the fuel lines and hoses at the same time is a good idea, as old rubber hoses can crack and cause air leaks. A skilled mechanic can complete this job in about an hour.

Choosing the Right Replacement Pump

When choosing a replacement fuel pump for your 1980 MGB, pressure is critical. The original SU pump operates at low pressure, typically between 1.5 and 3 PSI. Many aftermarket pumps found at auto parts stores deliver 5 to 7 PSI, which is too high for the Zenith Stromberg carburetor on your 1980 model and will cause flooding and poor performance. The original factory pump for your car is the SU AZX1307, which was introduced in January 1977 and is fully interchangeable with the earlier AUF 305 pump. For improved reliability, consider an electronic version like the AZX1307EN, which replaces the mechanical contact points with solid-state circuitry and eliminates the most common cause of pump failure.

Final Thoughts

The 1980 MGB fuel pump is conveniently located in the trunk, making diagnosis and replacement much simpler than on earlier models. Most pump problems can be diagnosed by listening for the telltale ticking sound, and many issues can be temporarily solved with a simple tap or a quick cleaning of the points. When replacement becomes necessary, make sure to use a low-pressure pump designed for SU carburetors. With proper maintenance and a quality replacement part, your 1980 MGB will keep running smoothly for many miles to come.

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