If the parking brake is weak, it'd be a good idea to replace the shoes; that would be a good opportunity to inspect everything else to make sure it's all good. Might not be a bad idea to check the disk brake pads before ordering the parking brake shoes to see if they need to be replaced as well. If you've done brakes before on other cars, this won't be a difficult job for you.

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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!)