RE: cruise control quit

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

> Here's a common one: if the clutch cylinder gets replaced, the switch must
> 
> be as well; same with brake cylinder.  They can't be re-used; once the 
> switch is removed, it's destroyed.  I bet the previous mechanic ignored
> the 
> Bently and reused the switch without telling anyone.  They're not very 
> expensive.
> 
... say what?  This is a new one for me!  What model/year of car is this
for?  I have worked on C/Cs for QTCs, 4ks and 5ks, and IME it is easily
possible to replace the clutch master cylinder or the brake servo or master
cylinder without having to touch the switches that the cruise control uses.


The thing about these switches is that the housing is made of plastic, and
there is a stamped spring steel nut that is used to attache the switches and
allow them to be adjusted.  If you set the switch too close to the
associated pedal, the return spring's force can be enough to damage the
switch housing ... that's the only problem I've seen.  

As regards C/C troubleshooting, the two items that have been most common are
broken hoses or fittings that open up the system and the adjustment of the
clutch/brake switches.  I need to look at the C/C on the '85 4k, while it
works for the most part, it doesn't have the ability to pull the throttle
all the way to WOT.  I have found that on some of the newer cars (like the
V8 quattro with automatic) the cruise control system actually receives power
from the transmission controller.  Fortunately the system on the 5000 is
pretty basic.  

HTH!
Steve Buchholz
San Jose, CA (USA)