The MGA fuel tank and its associated filler and sender hardware are the same across every factory variant of the model. All pushrod cars, 1500, 1600 and 1600 Mk II, and the Twin Cam share a single 10 Imperial gallon rear-mounted steel tank (12 US gallons, 45.4 litres), painted black and attached to the chassis by two strap-and-mount assemblies. Because this hardware is common to the whole MGA range, ordering is straightforward for standard-specification cars. Two factors do complicate ordering: the long-term internal condition of the original tank after six decades in service, and competition-tank specification, where larger-capacity tanks fitted as factory options require matched sender and gauge combinations to read correctly.
Standard 10-gallon tank
The standard MGA tank is a black-painted steel pressing carried on the chassis by two mounting straps. The fuel pipe and sender both exit the tank on its right-hand side, which determines the routing of both the main chassis fuel line and the sender wiring back to the dashboard gauge.
Replacement tanks are available as reproduction items; when ordering, the two mounting straps, their pads and mounting bolts are normally replaced alongside the tank itself, since 60-plus years of road use leave both the straps and the chassis mounting points prone to corrosion.
Why classic MG tanks fail, and what to look for
Classic MG fuel tanks are prone to internal corrosion, and the failure mode is distinctive. Condensation forms on the underside of the tank's upper surface whenever the car is left with a partly-filled tank through a temperature cycle, and over many years this moisture eats through the upper steel from the inside out.
The first external symptom is often a strong smell of petrol inside the cabin, a warning that the tank upper surface has been compromised and that replacement, not repair, is the appropriate course of action. For cars being laid up over winter or for longer storage periods, the best way to prevent corrosion in the tank and delivery system is to drain the fuel entirely before the vehicle is put away, rather than leaving a partial fill to sit through the storage period.
Q Parts replacement tank
To address these long-term corrosion issues, MGOC Spares has worked directly with the manufacturer to commission a range of replacement MGA fuel tanks under the Q Parts brand. The Q Parts tank is manufactured from zinc-plated steel for enhanced corrosion resistance, fitted with a removable drain plug for easier maintenance and storage preparation, and finished in a durable powder-coated black coating ready for installation. Each tank is supplied complete with a sender seal, lock ring and the drain plug.
When fitting, a fuel-rated non-setting sealant such as Hylomar applied to the drain plug threads is recommended, so that the plug can be removed easily in future service without the threads picking up or seizing.
Filler neck, hose and cap
The filler neck sits at the right-hand rear top corner of the tank and connects by a short hose to the filler extension that emerges through the rear tonneau panel near the lower right-hand corner of the boot lid. The filler cap is stainless steel, spring-loaded, and is released by a small tab marked 'lift' opposite the hinge.
Replacement filler necks, the short connecting hose, filler-extension hardware and the stainless cap are all available as service items. When replacing the connecting hose, ethanol-resistant fuel-filler hose specification should be used since the hose carries neat fuel during filling.
Sender unit and fuel gauge
The fuel sender is a float-type unit mounted on the right-hand side of the tank, wired to the dash-mounted fuel gauge which reads E, ½, F. The sender and gauge are a calibrated pair, the sender resistance range is matched to the gauge deflection, and a replacement sender should be to MGA specification rather than to a different BMC model's calibration, which would result in an incorrect reading. Sender gaskets, mounting screws and the spring contact on the sender are all service items available alongside the sender itself. A gauge that reads consistently high or low after a sender change usually indicates a mismatch between sender and gauge calibration rather than a fault in either component.
Competition tanks, 15, 17 and 20 gallon options
Alternative fuel tanks of 15 and 17 gallons were listed as factory competition equipment, and a 20-gallon tank was regularly fitted to works competition cars. These tanks are not direct physical substitutes for the standard 10-gallon unit, capacity, depth and sender mounting position differ.