Vacuum Lines On Heat / AC Diverter?

[kw502bbc]

I have a broken vacuum line on the heat/AC diverter on the back of the under-dash ductwork housing on the back side between the housing and the firewall. (1979Trans Am) It is the yellow line with a 90-degree elbow.

According to the manual, the housing and heater core has to be removed as a unit to access the diaphragm.

Is anyone familiar with a hack to get around all this?

It doesn't seem like a simple vacuum line replacement would be that involved.

The diaphragm has a white line for AC, and the yellow is for heat.

If the heater core goes bad, I may have to plug the line and take care of it later.

Thanks!

 

[Aus78Formula]

It's inside the heater box.

 

[kw502bbc]

It's inside the heater box.

Thanks for the reply!

Looks like it's going to be on hold for now.

 

[Aus78Formula]

A few blurry pictures: The vacuum valve is a push-pull type with a vacuum line at each end.

White and Yellow. The yellow line runs to the orange hose that runs through the rubber-slotted grommet to the inside of the case.

This is usually where the issue is.

The orange hose gets brittle, fades, cracks, and crumbles, and you don't have direct access to replace it as the vacuum valve port is inside the case.

The same line is pink on the pics of the Camaro box I had.

Is this what you are finding with a faulty hose?

 

[kw502bbc]

A few blurry pictures: The vacuum valve is a push-pull type with a vacuum line at each end.

White and Yellow. The yellow line runs to the orange hose that runs through the rubber-slotted grommet to the inside of the case.

This is usually where the issue is.

The orange hose gets brittle, fades, cracks, and crumbles, and you don't have direct access to replace it as the vacuum valve port is inside the case.

The same line is pink on the pics of the Camaro box I had.

Is this what you are finding with a faulty hose?

View attachment 3883View attachment 3884View attachment 3885View attachment 3886View attachment 3887View attachment 3888View attachment 3889View attachment 3890

This is exactly what the problem is. The #5 yellow line is broken and just lying in the top of the

A few blurry pictures: The vacuum valve is a push-pull type with a vacuum line at each end.

White and Yellow. The yellow line runs to the orange hose that runs through the rubber-slotted grommet to the inside of the case.

This is usually where the issue is.

The orange hose gets brittle, fades, cracks, and crumbles, and you don't have direct access to replace it as the vacuum valve port is inside the case.

The same line is pink on the pics of the Camaro box I had.

Is this what you are finding with a faulty hose?

View attachment 3883View attachment 3884View attachment 3885View attachment 3886View attachment 3887View attachment 3888View attachment 3889View attachment 3890

Yes, this is a perfect illustration of what I have.

The #5 yellow line is lying on top of the heater case.

The plastic elbow is fine, but the orange hose is broken at the end of the elbow.

These photos give me an excellent idea of what the case looks like and how it is mounted.

I will save these to my ever-growing stack of reference material.

I don't plan on driving the car in the winter, so I put a little rubber cap on the vacuum line for now and will repair it if I ever have to change the heater core.

On a positive note, the diaphragm isn't frozen.

Thanks for the info!

I appreciate it!