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MG MGA - Whitworth spanners needed on for MGA

Changing my oil recently made me realise there should be a list of what Whitworth spanners are required for working on an MGA (maybe Barney can add a full list to his site).

A few I have found are,

engine sump drain plug - 3/8 Whit. (18 mm will fit)
Flexible fuel line swivel nuts - 5/16 Whit (15 mm will fit)
Float chamber centre bolt - 1/4 Whit
Choke and throttle cable clamps - 3/16 Whit
Link nuts connecting levers on carbies - 1/8 Whit
Banjo bolt float chamber - 7/16 Whit
are there some others, what about where Posi drive screws are used also?

Mike Ellsmore

The starter switch also appears to have WW nuts on the terminals

The link nuts can be adjusted using an AF socket - at least I always used one without any probs.
The clamps for the cables are also AF on my carbs
dominic clancy

The most important Whitworth spanner/socket is the rear axle nut - something like 1-51/53", can't remember the exact size but their rare and expensive to buy. Someone once said that they are either extremely tight or slack and I'd be interested in checking mine if I could get hold of a socket. What about the UK owners contributing to a shared 'rare tool resource'?
J H Cole

Not sure if it is Whitworth, but the nut is 1-61/64". The important thing about it is that it is octagonal, not hex like most other nuts.
Jeff Schultz

Barney has a page about sources for the hub nut socket.

I got one of the sockets for a Ford 4x4 from a local auto parts store, and it worked fine.
Jeff Schultz

If you measure the 1-61/64" octagonal rear hub nut socket, you will find that it is coincidentally very close to 50mm.
Del Rawlins

Some current dirt bikes use a 50mm octagon cap on the forks. This wrench is available, but don't know if it is hefty enough. Haven't seen a 50mm octagon socket.

Best bet still seems to be the 4x4 hub socket. I got mine several years ago for less than $10.

Jeff Schultz

Jeff is right. Go to a Checker/ Schucks/Kragan or Auto-Zone and rent (often free with a deposit) the 4x4 front wheel hub socket set (set of 4 or 5). There's one socket in the set that fits nicely to the MGA rear hub nut. The socket that Moss sells (a pressed tube) is a piece of junk.

The drain valve in the side of the engine block is a whitworth. I don't have any whitworth wrenches yet, but a thin 15mm wrench will just barely work.
Del Rawlins

Then there's the drain valve on radiator...
Pete Tipping

The link nuts on the carburetors are all 2BA (the british equivalent of American machine screws). The nut on the starter power stud is 1/4W. For a chart comparing the across the flats measurements of wrenches (American, British and Metric), go to:
This will show what wrenches can be substituted for most Whitworth or BSF fasteners (BSF fasteners use a Whitworth wrench, one size smaller i.e. a 1/4W wrench fits the head of a 5/16 BSF bolts).

There is a companion chart of standard threads (American, British and Metric) at:
Cheers - Dave
David DuBois

The nut connecting the "casing, motor to wheelbox" to the windshield wiper motor is also Whitworth, at least on the 1500.

58 A
Larry Hallanger

In answer to the original question, my MGA has 360,000 miles on the clock, I do all my own maintenance (including complete restoration), and I do not own any Whitworth spanner. Some of the fasteners may be Whitworth, but I always find a useful wrench among the inch sizes (and a couple of adjustable spanners).
Barney Gaylord

The banjo bolts for the hydraulics are Whitworth thou I do not recall the sizes.
Dave De Fauw

This thread was discussed between 15/07/2007 and 27/07/2007

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This thread is from the archive. The Live MG MGA BBS is active now.