Elton John is reportedly facing a health crisis – and has resorted to desperate measures to hide it from his fans. RadarOnline.com can reveal John can barely walk but refuses to let it affect his public image. In a recent red-carpet appearance at the world premiere of his documentary, Elton John: Never Too Late, John stunned his fans by arriving in a custom purple golf cart. Insiders claim this move was to hide the Rocket Man singer’s reliance on a wheelchair. The insider said: “Elton refuses to be seen as weak. “He’s so determined to maintain his larger-than-life image — but the truth is he c…