Here you go. The tool costs about $100 here in the states, but there are a few people renting the tools out as well; search here and on eBay. BMW 5 Series (E39) 1997-2003 - Rear ball joint DIY, how to remove and install - YouTube

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2001 X5 Sport 3.0/5-speed
1998 318ti/5-speed
1988 735i/5-speed
1984 528e/5-speed (soon to be M20B25-powered 525i!)