Lagging Cruise Control

[Kirby J]

I found an easy fix on BRICKBOARDS for an intermittent and weak cruise control on my 92 740. If you remove the brake pedal switch, and open it up, you will find a small orange rubber O-ring in the bottom of the switch. Remove that O-ring, cover it in petroleum jelly, or some other mid-weight grease, and replace. Re-install the switch and you are cruising again! Or, you could pay $35 for a new switch.

Kirby J

[Zdadgeezer]

I did not compare part numbers and would recommend you check from year to year and model but what Worked on my '94 940 T is this.
The "O" ring is easily replaced I used Silicone 3/16 ID x5/16OD x 1/16 w -DUR 70. Seemed to be an exact match.Since the inner surface of the original ring was pretty munged up and stuck to the switch shaft. Also getting the switch apart can be destructive(breaking locking tabs of which there are 4). I avoided breaking them by making a slip wedge /spacer to facilitate opening out of the plastic packaging used commonly for headsets etc.. by cutting a strip about 2 inches wide and several inches long and slipping it under the tabs as I wrapped the plastic around the switch. Protect your fingers because it can be sharp. Sorry I didn't think to use the camera. Would have been a pretty tight fit anyway under the dash given my overwhelming physique. Don't forget to use a little petroleum jelly to preserve, lubricate and seal the "O" ring. Not get under the dash.