lucidardor

Quick question - I've been browsing through the forums and found a lot of posts about vacuum issues, but I couldn't find any answers. Firstly, i have a 1984 - Crossfire.

So, basically the car was running fine, and I went on a short road trip. On the drive home, the cruise control started cutting out when I pressed the excel button. I noticed that around the same time the A/C started blowing warmer and warmer. Eventually, the cruise control stopped working completely, and the A/C was blowing hot as if the heater was on. So I turned off the cruise, and the windows went down. When I got off the freeway, the break pedal went all the way to the floor, and I felt a weird vibration in the pedal. Also, the engine was idling kind of roughly.

Initially, I did not think the problems were related, but now that I think about it, both the brakes & the cruise control are powered by engine vacuum. And the A/C & heater controls are also powered by vacuum. So now I'm starting to think there's a loose or busted vacuum line somewhere.

Because I did not suspect a vacuum problem for the breaks & A/C, the first thing I did was to check the brakes. Fluid was good, so I bled the system but there was no air in the system (the pads are new ), but the pedal still goes to the floor - to the point to where I have the pedal depressed all the way to the floor, and the car creeps forward at stop lights.

I checked the A/C, and the system is full, and the compressor is engaging properly. The cruise control doesn't work at all now. I'm really only concerned with the A/C & the breaks. Could the break booster have failed? I really don't know how to check vacuum pressure, and I have no idea where to even begin looking. Once again, this is a Crossfire, so no plenum or fuel rails. Any input is appreciated.

renchjeep

Your brake issue sounds like a master cylinder bypassing internally. As far as I know, when the booster goes out or doesn't get vacuum, the pedal won't sink, but pedal effort will be quite high. For the other two issues, I would suspect a vacuum issue like a broken or collapsed line somewhere.

lucidardor

I agree about the brake pedal. I only grouped them together because the problems all manifested simultaneously. I do however think the A/C and cruise issues are vacuum related. Perhaps you're right about the brakes. I'll investigate that problem deeper.