Is there such a thing

[jamber2541]

Is there such a thing as a vacuum leak inside the cab affecting the way the engine is running. My friend swears that he can hear a vacuum leak inside his cab and says his engine has ran like crap ever since it started ??

 

[dyeager535]

I can't recall the routing, but there is a vacuum line on the brake switch, on cruise control equipped trucks.

 

[Can Can]

Yes, it's possible. All the heater controls as well as the diverter doors on an AC-equipped truck are vacuum-operated.

 

[NJBLZ]

my trucks have heat only, which is controled by cables, but trucks with air conditioning have vacuum hoses and cables running out of the back of the control unit.


on ac trucks the hot-cold setting is cable operated

when you use the off-max-norm-bi lev-vent-heater-def it sends a vacuum signal through little colored plastic vacuum lines.


they all tee off from a regular black vacuum line from the engine, but i dont know exactly were it is. you can plug that one and see if it changes anything. i had a 78 monte carlo that they dry rotted and desintegrated on.

 

[mdm365]

also if it has a power brake booster it could be leaking at the firewall inside the truck.To test this all you have to do is pinch the 3/8 hose to the booster. mike

 

[JEBSR]

also if it has a power brake booster it could be leaking at the firewall inside the truck.To test this all you have to do is pinch the 3/8 hose to the booster. mike

If its loud enough to hear easily and make that much differance in how the vehicle runs, it probably is the booster.