What is the procedure to adjust the parking brake on the W126? The pedal on my 1989 300SE moves close to the floor before the brake engages, and it's weak at that. Does adjustment require the removal of the wheels and possibly the rotors, or is it just the tightening of a cable running along the undercarriage?

Thanks.

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2004 E320 Wagon
1989 300SE
1998 Range Rover 4.0 SE