Loss of Speed Control

alfredmay wrote:
Older Ford vehicles used manifold vacuum to operate cruise control. I used to tow with a Ford van and my buddy had a Ford class C. We both would lose cruise going up long grades. Look for a vacuum leak. I believe the vehicles also used a vacuum storage canister....... check that too.

Those sound like excellent ideas... if I had any idea how to do it :-)

The sudden and complete loss of the system makes me think that it isn't a vacuum leak from my understanding of how these things work (unless it was huge leak like a tube coming loose from a fitting). Nevertheless, I did look over any tube I thought could be part of the system as well as any canister I thought could be holding a vacuum... nothing obviously leaky. The speed control system stopped working while almost coasting downhill at 55mph or so, although there had been long grades prior to that.