81 cruise control problems

[RandyE]

Hi all. I have a perplexing problem. I had the valves ground and on my test drive I hit the cruise control. The truck instantly started accelerating. I hit the brake pedal but cruise wouldn’t disengage. I turned the switch off but it was still stuck on. At about 80 mph I turned the ignition off, went to neutral and stopped the truck. When I checked the servo it was pulled right back in.
I was thinking the vacuum release on the brake pedal was possibly stuck but why would the cruise go to instant wide open throttle?

 

[Ricko1966]

Sounds like when you pulled the manifold you got some vacuum hoses routed wrong.

 

[RandyE]

I only unhooked the servo and manifold lines but now that you mention it I bet I reversed them. I’ll check that.
Thanks Ricko.