The tool for this job is a good quality '12 point' socket. 1/2 inch drive will be adequate. Sears, and the usual auto parts stores will sell them. Your safety is at risk when you use poor quality tools.

However, removing this nut MUST be approached with the thought "you will have only a single chance to properly remove it". If the wrench slips and mars the flats on this nut, you will play hell getting it off.

All sockets are manufactured with a bit of taper or 'lead' (rhymes with bleed) machined into the opening of the socket. This is to aid the mechanic in placing the socket over the nut. In this case, the lead is not your friend, but is your foe.

The lead will allow only half of the available 'flat' of the nut to be against the faces inside the socket. This tends to force the socket to 'cam-out' and off of a shallow nut, damaging the nut, and injuring the mechanic. I strongly advise the mechanic to grind the end the socket to remove the lead, or better yet, have a friend with a lathe cut the socket face square.

An additional 'dodge' known to most mechanics is to rub a smear of valve grinding compound onto the flats of the nut OR inside the face of the socket. The grit in the valve grinding compound greatly increases the 'grip' of the socket reducing cam-out or slip.

Be very careful, the torque value to remove this fastener will be around 100 lbs/ft. A straight, steady pull is required and avoid jerking. The vehicle must be secure on jack stands and or blocks.

Below are two photos, one showing a typical 12 point socket and depth of the lead, and a package of valve grinding compound, both avalable at most auto part stores.

Best wishes,
Dick

PS: A shot of a known brand of Penetrating Oil, applied 30 minutes prior to removing the nut, is worth considering. Aero Kroil is my favorite, but Liquid Wrench and others are readily available.

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