Cruise control surging
 

I have a 1986 560 SEL with a cruise control that works fine with the exception of "surging" when the car is going down hill. When it starts I disengage the CC, then activate it when the terrain levels out and everything is back to normal. I have checked the archives but can't find anything relating to this problem. Any ideas?

I'd say it is trying to tell you that you are going to SLOW. :) 560's like triple digit speeds!

It may help to clean and re-lube the linkages between the cruise control and throttle. They get pretty gunked up. Pop them apart, clean them, and re-lube with ATF or similar light oil.

Some CCs seem to just surge when not under load. You can try pressing the accelerator slightly--that'll sometimes eliminate the surge.