1.                  Clean, apply release fluid, remove and refit nut as per the removal of other types.
2.                  Now the most important part, you must use a heavy metallic object held hard against the opposite side of the handle adjacent to the tapered head of the pin.  This will counteract the force of the blows needed to drive the pin out and therefore prevent damage to the aluminium casting.
3.                  Do not under any circumstances attempt to drive out the pin without use of supporting weight.

1.                  Always check thoroughly the condition of used pins particularly the threaded section, this will stretch quite easily if over-tightened.
2.                  If in any doubt always use a new cotter pin, new ones should always be used when refitting brake levers.
3.                  There are rare incidents when normal methods fail to remove a cotter pin due to the fact they were originally fitted with far too much force. If this should happen, it is in order to use gentle heat from a blow lamp to the surrounding area. Do not use a welding torch, the excessive heat generated could alter the temper of the metal.

EDDIE LOADER MA7C NOVEMBER 92 with many thanks.