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MG Midget and Sprite Technical - Front pulley what size socket?

Preparing to do my timing cover oil seal on my 1500 (UK)
Does anyone know what size socket the nut on the front pulley requires?

Jon Warren

Hi Jon, I used a very large adjustable spanner!! This item is resident in my garage if you want to borrow it. Mail me I'm in South Shields
S McGregor

Good luck Jon. If it's the first time the pulley has been off, you'll struggle, even with a proper tight-fitting socket (I wouldn't attempt it with an adjustable). The first time I tried, I gave up after a comical hour with a long section of iron pipe, breeze blocks, railway sleepers - and hefted the whole lot into the back of the car and took it to my nearest "Mr. Clutch" For the price of a pint they whizzed it off with an air wrench in approximately 5 seconds.

So offhand, no, I don't know what size socket
Steve Clark

If I remember correctly it is 1"7/8 and is done up very tight! Quite why it is so big and so tight I don't really know, I did once have one come off while driving along. It made a very loud bang and was not very difficult to find at the roadside!

Good luck Carl
C Bintcliffe

Nope its not 1 7/8 because thats the size the rear hub nut uses and Olaf tried my socket for the rear hubs and found out the nut at the front of the 1500 engine is smaller. He had to shim the socket. Eventualy he had to bring the block to a specialist with an impact wrench to loosen it.

Bas Timmermans

It is 1 13/16" 0r 46 mm.

Richard 1500 5 speed

I have just measured the nut with a pair of calipers and it measures 46.00mm or 1.811" which is 1 13/16" go figure!! Triumph have a lot to answer for!

C Bintcliffe


The size is likely due to it needing to provide an even load over the face of the pulley which is taking the clamping load and commonality with the rear axle nut might be useful. The tightening torque has to be high enough to generate a clamping load sufficient so that friction stops movement of the pulley and timing sprocket relative to the crank. The woodruff keys being for alignment not torque transmission.
David Billington

I see that David but some other manufactures seem to manage with much smaller fastenings, Interestingly I managed to do quite a few miles without the bolt at all and then fitted it back on in a car park at Le Mans having borrowed a suitable sized open ender from the toolbox of a pre war Bentley! I think he used it for tightening up his points or something!

Cheers Carl
C Bintcliffe

I concur with C Bintcliffe's measurements: 46mm 'across the flats'.

Back in 1979, when I had to remove the crankshaft pulley on my 1500, I got myself into such a 'tiz' (by futile attempts at nut removal using sockets and adjustable spanners)that my father enlisted the help of a local mechanic who visited my house. The mechanic proceeded to free off and remove the nut using club hammer blows and a cold chisel. The experience has remained with me! Yes, the flats of the nut suffered slightly, but the mechanic got the bar steward undone in a matter of seconds.

If the nut gets badly damaged in the 'hammer/chisel' process, buy a new one - but they're not cheap at approx 12 (part # 155357). Use plenty of Loctite thread-seal when reassembling using a socket/torque wrench and extension bar.
Andy Hock

Thanks for the replies ,
managed to remove it , 46mm socket 3/4 " drive with a sliding t bar. Car in first gear and the wife standing on the brakes, hit the bar with a geet big hammer.

I was well pleased, then I found that the mg specialist I had ordered the new seal and gasket from had sent me the correct items for a ....1275 engine.

So itwill be Tuesday before I get then correct items, unless anyone in North east england can help?


Jon Warren

Glad you got it sorted!
The method preferred by most triumph sptifire owners is to warm the engine, then fit the socket with a bar that would foul the chassis crossbar.
Then start the engine. The engine would fire and the jolt would undo the nut.
Only thing to watch for is the socket and bar flying off at high speed.
T Dafforn

This thread was discussed between 11/09/2009 and 13/09/2009

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