Grouch"o front end needs suspended,wheel off , i slacken fork cap while still clamped in yolks [ triple tree], then yolk bolts. slide offending fork out, loosen fork cap, [ apply pressure as unscrew] keep pressure on as fork spring unloads as cap unscrews. take out spacer& spring, turn fork upside down into bucket, to empty oil. then into vice, [ with wooden blocks] old woodwork vice is best, thers allen screw in bottom , this may need airgun as to spin faster than captive insde fork, then slide out tube, seal will be held by circlip,
then pry out auld seal , take care not to damage face, ,, bang in new seal with similar sized socket,,, vall"a..