1972 MGB Fuel Pump Location: A Complete Guide for Owners

If you own a 1972 MGB and need to find the fuel pump, here is the most important thing to know: the factory fuel pump is mounted under the car, on the right side, just forward of the rear axle. On a chrome bumper 1972 MGB, the pump is located on the axle side of the bulkhead, behind the right-hand seat, forward of the axle, and next to the right-hand battery box . This is an exposed position under the car, making it vulnerable to road debris, moisture, and corrosion . Accessing it typically requires removing the right rear wheel .

Why the 1972 MGB Fuel Pump Location Matters

The 1972 model year is a chrome bumper MGB, and the factory SU fuel pump was mounted in a specific location that differs from later rubber bumper cars. On the 1972, the pump is mounted under the car, on the right side, just behind the battery box. The original pump is an SU reciprocating pump that delivers fuel at low pressure, around 3 psi . The pump is designed to be a "pusher," meaning it works best when mounted near the tank, not in the engine bay .

How to Access the Fuel Pump on a 1972 MGB

The fuel pump is located under the car, so you will need to raise the vehicle safely using jack stands or ramps. Removing the right rear wheel gives you much better access . Here is what to look for:

  1. Location: Look under the right side of the car, just forward of the rear axle. The pump is mounted on a bracket that is attached to the body, near the battery box. The top of the pump fits through a hole in the battery box .

  2. Visual Identification: The original SU pump has a distinctive "top hat" cover. The pump is mounted on its side, with the outlet port at the top and the inlet port at the bottom. The electrical end of the pump has a plastic cap with a spade connector for the 12v power supply .

  3. What to Expect: The pump is held in place by a bracket with two bolts. The bracket uses a rubber support ring to cushion the pump . Fuel lines connect to the pump using banjo fittings with copper washers. There is also a breather tube that connects to the pump body .

Common Problems with the 1972 MGB Fuel Pump Location

Because the pump is mounted under the car, it is exposed to the elements. This leads to several common issues:

  • Corrosion and Pitting of Contact Points: The SU fuel pump uses contact points that corrode and pit over time, especially with modern ethanol-blended fuel . The pump's internal diaphragm also deteriorates faster with ethanol fuel.

  • Poor Ground Connection: The fuel pump ground is shared with the license plate lights. This connection is in the boot and can corrode, causing intermittent pump failure . A bad ground is a common cause of the pump not working.

  • Air Leaks: The metal fuel pipe that runs from the tank to the pump can corrode, introducing air into the system. This changes the fuel mixture and causes running problems .

  • Pump Failure: The SU pump is known to fail suddenly while driving. A common symptom is the engine dying out, then restarting after a few minutes, only to die again . If you cannot hear the pump ticking, it is likely the pump has failed.

How to Diagnose a Fuel Pump Problem on a 1972 MGB

Before you replace the pump, check these things:

  1. Listen for the Tick: Turn the ignition on. You should hear a rapid ticking sound from the pump as it fills the carburetor float chambers. After a few seconds, the ticking should slow to one tick every 10-20 seconds. If the pump is silent, it may be dead .

  2. Check for Power: Use a multimeter to check that the white power feed wire has 12v+ when the ignition is on. The voltage should be within 0.2v of the battery voltage .

  3. Check the Ground: Use a spare wire to connect the pump body to a clean ground point on the car. If the pump starts working, the ground connection is bad and needs to be cleaned .

  4. Check for Blockages: Before buying a new pump, remove the fuel feed hose from the carburetor and point it into a container. Turn the ignition on. If the pump runs like a "demented jack hammer" but delivers no fuel, the tank pick-up filter screen may be blocked, or the pump is drawing air .

How to Replace the Fuel Pump on a 1972 MGB

Replacing the fuel pump is a job that requires crawling under the car. Here are the steps:

  1. Safety First: Raise the car on jack stands or ramps. Remove the right rear wheel for better access .

  2. Disconnect Everything: Disconnect the unions (fuel line fittings), the breather pipe, and the electrical connections. Loosen the two bolts on the pump bracket and remove the pump .

  3. Retain the Rubber Support Ring: You will need to keep the rubber support ring from the old pump to fit onto the new pump .

  4. Inspect the Hoses: Check the rubber fuel hose. If it looks hard, aged, or cracked, replace it with new E10-resistant fuel hose . Use new washers for the banjo connections .

  5. Install the New Pump: The new pump must be oriented correctly. The outlet port (marked "TOP" or "OUT") must be at the top, and the inlet port at the bottom . Tighten the bracket, reconnect the fuel lines, breather pipe, and electrical connections.

  6. Test the System: Turn the ignition on and listen for the pump to prime. Check for leaks.

What Type of Pump to Use for a 1972 MGB

The original SU pump is a low-pressure pump, delivering about 3 psi of pressure . If you buy an aftermarket pump, make sure it is a low-pressure pump (1.5 to 3 psi). Many aftermarket pumps from auto parts stores deliver too much pressure (5 to 7 psi), which will overwhelm the float valves in the SU carburetors and cause flooding. You would need a pressure regulator to use such a pump .

The original SU pumps used on the 1972 MGB include the AUA 150, AUB 182, and AUF 301 models . These pumps use points that can be cleaned or replaced. New SU pumps are available from Burlen .

KEMSO Fuel Pump Recommendation

If you are looking for a reliable replacement fuel pump for your 1972 MGB, consider the KEMSO brand. KEMSO fuel pumps are high-performance, OEM replacement parts designed to meet or exceed factory specifications. Every KEMSO fuel pump comes with a lifetime warranty, giving you peace of mind that your investment is protected. Whether you are restoring your classic MGB or just need a dependable daily driver, KEMSO offers quality you can trust. Visit their website at https://www.kemsoracing.com/ to explore their full lineup of fuel pumps and find the right fit for your vehicle.

Final Thoughts on the 1972 MGB Fuel Pump Location

The fuel pump on a 1972 MGB is located under the car, on the right side, behind the battery box and just forward of the rear axle. This location makes it accessible but vulnerable to corrosion and road debris. Regular inspection of the pump, fuel lines, and electrical connections is essential for reliable operation. If your pump fails, you can replace it with a new SU pump or a quality aftermarket replacement. Remember to use only low-pressure pumps (1.5 to 3 psi) to avoid damaging your carburetors. For a dependable replacement, check out KEMSO fuel pumps at https://www.kemsoracing.com/.


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