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MG Car Repair/fuel tank drain plug on a 1972 MGB


QUESTION: I was given a 1972 MGB that has sat for 3.5 years in a garage.  Does the fuel tank have a drain plug?  If not, what is the best way to remove fuel from the tank?  Also, is there a good way to check for rust in the tank without removing the tank?  Thank you.

ANSWER: I believe there is a drain, but am not 100%. Just take a look and see, it should be obvious if there. Take a good ok at what comes out and look for junk,rust,etc.
If there is no drain then I'd drop the tank as it is not difficult to do. You can flush the tank with kerosene whic h is safer than messing withi gas. Acetone also works better to dissolve varnish.  If it had old formula gas and you live in a dry climate, it may not be too bad. If it has the newer E-10 in it and you live in a damp climate there is likely more junk and varnishi, and rust. If you we're lucky maybe the previous owner used a gas stabilizer?

Good luck

---------- FOLLOW-UP ----------

QUESTION: Brian, thanks for the help.  The car does have a fuel tank drain plug. There doesn't appear to be any rust in the tank. Another question- I want to convert the electrical system from a 2 6V batteries to a single 12V battery.  Can you guide me through it?  Also, aside from the battery, do I need to change anything else in the electrical system?  Thanks again for your help.  Randy

The following is from the Moss Motors web forum. The part numbers such as 241-040' etc., are Moss Motors part numbers. Since the car is already 12V and you are not changing the "ground" of the car electrically, there is nothing else to change or worry about. I did this myself to a 72 B I once owned and it was pretty easy to do - take your time. I wish I could remember what battery group size I used - group 24 perhaps?  Also, you can buy batteries of any given size with reversed terminals meaning the terminals themselves are opposite.sides from the " regular" battery. This can  make installation easier if needed to fit the cable lengths.

Also check this page/PDF:
The following suggestions have been compiled from a number of sources, but they draw heavily on the conversion of a 67 MGB to one 12V battery that was done by one of the staff. These instructions are somewhat general in nature, and it will be up to you to improvise on some of the details as needed to suit your situation.

Install the 241-040 or GAC4096X battery box liner in the right hand side battery compartment.
The original cable that goes to the starter will not require any modification.
Relocate the battery ground cable from the left hand side battery compartment to the right hand side compartment. Arrange the ground cable to make it impossible to accidentally connect the cable to the wrong terminal.  
If it is still there, you can completely remove the short series connecting cable that goes from one battery compartment to the other.
Drill holes in the battery box liner for each of the two battery cables.
If you select grommets carefully, you can achieve a very clean cable installation and the inside of the liner will stay cleaner longer.
You will need to obtain a battery tie-own bracket locally, and more holes will be required for the bolts that secure the tie down to the chassis. The original battery support framework is very useful for this purpose, so we do not suggest that you remove it unless it is totally rusted out. If the original battery support framework is gone, some careful thought should be given to the method you choose to secure the battery. We have been told that you can use an adjustable nylon strap to secure the battery inside the battery box liner with an adjustable nylon strap.  Aside from the obvious safety issue, a battery that is shaken violently or allowed to vibrate excessively will not last as long as it would otherwise.
A second battery box liner can be installed on the left hand side and it makes a really useful storage bin for tools and spare parts.

If you decide to use the original battery support frameworks, inspect them carefully. After many years exposure to rain, salt, and battery acid, the metal can be severely deteriorated. If so, they will need to be replaced before you fit a new battery.

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Brian Warmuth


General questions regarding most MG autos from 1950 through 1980 - primary are the TD, MGB, Midget and MGA.


Over 30 years of working on and restoration of MGs

Ohio Chapter New England MGT Register, AACA

BA, and MS, from WVU

Awards and Honors
several local regional awards for restorations

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