CMP Rim Disassembly Tip

[rob love]

I concur with the use of the deep socket. Mine was from NAPA with the part number of 12628M for the price of $19.59. Worth every penny. I do prefer an impact gun over a power bar though. I think it results in fewer broken studs.

[Tony Wheeler]

Something else I've found makes a difference (with wheel nuts anyway) is to strike the nut after heating, using a length of pipe of suitable ID to slide over the hex and seat on the flange (eg. 1'' water pipe for 15/16" wheel nuts). If you rest the other end on a jack stand you can take a full blooded swing without fear of injury and bash away to your heart's content, which as we know is always highly satisfying! Unfortunately on this particular occasion I had yet to equip myself with the correct tools, and consequently failed to remove a single wheel nut! However I did succeed in testing to destruction two double hex sockets and a 1/2" drive breaker bar, which sheared off through the actual 1/2" square stub. Returning some weeks later with a 3/4" breaker bar and 15/16" impact socket I had no trouble whatsover, although some nuts required the assistance of the property owner, made possible now by the use of a much longer extension pipe of far heavier gauge, from which both of us could hang our full weight and bounce up and down! With that kind of torque I found it amazing that not a single stud broke, which leads to believe that most of the force required is due not to seized threads, but to seizure of the flange surface on the wheel. That might explain why striking the flange directly can often help, so it may be worth trying with seized rim nuts as well. It certainly can't hurt and can be quite therapeutic, esp. if you upgrade to a sledgehammer!

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[Richard Farrant]

To us "old school" mechanics who still use Whitworth spanners and sockets, (and measure in Inches) we would use a 5/8" Whit socket for these nuts.
The wheels were to a War Office spec. hence why the British sizes.

The actual hex size is 27.94mm so not much in it.

[rob love]

Ahhh, so that's the explanation of the oddball size by today's standards. I had a look on a chart on this page: http://www.dummett.net/ime/website/i...ner_sizes.html and it shows a difference of under 2.5 thou of an inch between the 28mm and the 5/8 Whitworth/11/16 BSF size. That difference can more than be made up by the layers of paint on the nut.

Just checked the NAPA page, and no Whitworth is listed, although of course they can be had form ebay and elsewhere. I think I'll be ok with the 28mm.