I just installed a new vacuum pump and got my brakes back up to par and have good vacuum, however I still have the issue of the air only coming out of the defrost, unless I plug the 1/8" black vacuum line under the hood that goes to the opposite side of the fan motor ( Is that the plenum?) It's not the line going to the blender in the corner of the fender and the firewall, but the other one. The line itself is getting good vacuum. Anyone know what could be going on inside the box that could be creating my loss of vacuum? Also, I did plug that line so I could get cold air out of my vents. Will anything bad happen by having the line disconnected from the plenum?

Scott

 

I have the same problem. did you ever find a solution? Also, which hose are you talking about plugging, I cant get the air to come out of the vents no matter which vacuum hose i plug?

 

As you work from the passenger side on the fire wall, in the corner is a blender (little plunger actuated control), which is the first one. The second goes to the vacuum bottle (I stole the term from another member), which is right next to the condenser coil next to the HVAC fan. This is the one I plugged. Since you've plugged all your lines and the vents still don't work, I would say you have a vacuum leak somewhere. The 1/8" lines get very brittle and even pin holes will cause this problem. Check them all very good. Especially if your brakes work good (not hard to push at all). I think my problem is inside the "vacuum bottle". I think yours is before it.

Scott

 

Thanks for the info. I really appreciate it. If i figure it out i will let you know. since I live in Florida, I really would rather have the vents then defrost. so I ziptied the plunger under the dash that changes it from defrost to vent. Do you think that will mess anything up? thanks again
Travis

 

You need to find the vacuum leak on the HVAC line that is under the hood around the air box. If you find and fix this leak, your problem will be solved.

 

I agree with mjonesjr. You need to find the leak under the hood. Go over those small lines with a fine tooth comb. You can use rubber vacuum line to replace any breaks, cracks or holes. Some guys even tape them. I haven't gotten into the vacuum bottle on mine yet, but I will let you know what I fine when I open it up.

Scott