You don't need to remove this nut to replace the brake shoes, only to
replace  the bearings.  When and if you do need to remove it, rent a
3/4" drive electric impact hammer and socket to do the job, it is the
only way to loosen this nut sometimes.

--
Stuart MacMillan
Seattle

'84 Vanagon Westfalia w/2.1
'65 MGB (Daily driver since 1969)
'74 MGB GT (Restoring sloooowly)

Assisting on Restoration (and spending OPM):
'72 MGB GT (Daughter's)
'64 MGB (Son's)

Stripped and gone but their parts live on:
'68 MGB, '73 MGB, '67 MGB GT