Timmytorco

Anyone with a 93 motor running cruise in an old body? Is there enough vacuum to run the cruise? I figure it should if it runs the brake booster.my truck is a 74.

Fordzilla

I'm a little unclear on your problem...Are you saying you have a Cummins diesel in your '74 Dodge (which never had a diesel from the factory) and you want to add a vacuum operated cruise control?...If so, diesels don't make vacuum...Your vacuum operated brake booster will need a separate vacuum pump which can also power any other vacuum operated accessories......Ben

Timmytorco

I realize a diesel doesn’t make vacuum, that’s what the vacuum pump does, the one that came on it from the factory I assume. And I realize they didn’t offer a Cummins in 74. It’s a 93 re bodied with a 74.
so if I add a reservoir, will I have enough vacuum to run cruise? It runs the brake booster with no issues, or do I need to scavenge a cruise off a newer truck with an electric throttle actuator, and does anyone have any wiring diagrams if that’s the case?

oliver foster

The cruise control on the 1st gen Diesels use a vacuum line...
Same idea.

Timmytorco

Thank you Oliver. I have access to the stalk and system from a 78 I think so it’ll look right. Amd, I have a 76 factory service manual, which helps with the wiring.

texasprd

I have a '96, so I qualify my answer by saying I don't know what may have changed between the 1st & 2nd generation trucks - but the 2nd gens don't have a vacuum reservoir and 2nd gen cruise control also requires vacuum as does power brakes. If the '93 you used as a base didn't have a reservoir, then I don't think you need one either as long as the vacuum pump, vacuum lines, and any vacuum-actuated vent controls are all in good condition.

Timmytorco

Thks. Being a 74 body the controls are all cable. And I won’t worry about an additional reservoir as running cruise and repeated brake applications will not happen at the same time. I figured if it could run a booster, it would run cruise. I didn’t know the first gen trucks ran a vacuum actuator. I thought they’d be electrical by then. Off to the scrap yard we go…….

Timmytorco

I ended up buying a new in box system from the 80s for $40 off marketplace. Two hours later I was cruising down the road at 75mph with my foot not touching the pedal. No vacuum actuator issues at all.