76 a/c
09-08-2014, 12:11 PM
#1
Burning Brakes
Thread Starter
76 a/c
Hi all, I am getting a really weak flow of air through my air vents on my 76. I checked the A/C fan motor and it seems to be running just fine; Any ideas what could be the cause? Thanks.
09-08-2014, 12:55 PM
#2
Racer
Have you made sure all the duct work is fully connected in the dash? I've noticed sometimes the ducts don't fully connect, causing air leaks and low pressure.
Also, you might pull the blower motor and, somehow, vacuum out the airbox: often it's full of leaves and other debris, inhibiting airflow through the system. See this thread.
Lastly, once all that is clean and in good working order, swapping the blower motor for one from a C4 is a common mod for stronger airflow. You'll have to fab a spacer for it, but there are multiple threads here about it. Here's a recent one.
Good Luck.
Also, you might pull the blower motor and, somehow, vacuum out the airbox: often it's full of leaves and other debris, inhibiting airflow through the system. See this thread.
Lastly, once all that is clean and in good working order, swapping the blower motor for one from a C4 is a common mod for stronger airflow. You'll have to fab a spacer for it, but there are multiple threads here about it. Here's a recent one.
Good Luck.
Last edited by Kris Tunetso; 09-08-2014 at 01:30 PM. Reason: Added links.
09-09-2014, 10:48 PM
#3
Burning Brakes
Thread Starter
Have you made sure all the duct work is fully connected in the dash? I've noticed sometimes the ducts don't fully connect, causing air leaks and low pressure.
Also, you might pull the blower motor and, somehow, vacuum out the airbox: often it's full of leaves and other debris, inhibiting airflow through the system. See this thread.
Lastly, once all that is clean and in good working order, swapping the blower motor for one from a C4 is a common mod for stronger airflow. You'll have to fab a spacer for it, but there are multiple threads here about it. Here's a recent one.
Good Luck.
Also, you might pull the blower motor and, somehow, vacuum out the airbox: often it's full of leaves and other debris, inhibiting airflow through the system. See this thread.
Lastly, once all that is clean and in good working order, swapping the blower motor for one from a C4 is a common mod for stronger airflow. You'll have to fab a spacer for it, but there are multiple threads here about it. Here's a recent one.
Good Luck.
Ok, KrisTunetso, I'll give it all a try. Based on your response it's not likey a vacuum problem correct?
09-10-2014, 11:31 AM
#4
Racer
Anything's possible with cars this old but it's probably not vacuum-related. If it were a vacuum issue you'd be having problems with only getting hot air, or only cold air, or lukewarm air because of a malfunction in the vacuum operated actuators in the system. But weak airflow, based on what I've learned from reading around here is likely one of the 3 things I mentioned above. Or, I just recently read in another thread, that giving the blower motor a larger ground wire may help it blow harder. It might be in the thread I linked above: if not, search "Blower motor" and read the threads until you find it. 
Problems with the vacuum lines and actuators is why many replace the entire HVAC system with a kit from VintageAir or similar: it's all electric and eliminates vac problems. It's expensive though.
Problems with the vacuum lines and actuators is why many replace the entire HVAC system with a kit from VintageAir or similar: it's all electric and eliminates vac problems. It's expensive though.
Last edited by Kris Tunetso; 09-10-2014 at 11:38 AM.
09-16-2014, 11:48 AM
#5
Burning Brakes
Thread Starter
Anything's possible with cars this old but it's probably not vacuum-related. If it were a vacuum issue you'd be having problems with only getting hot air, or only cold air, or lukewarm air because of a malfunction in the vacuum operated actuators in the system. But weak airflow, based on what I've learned from reading around here is likely one of the 3 things I mentioned above. Or, I just recently read in another thread, that giving the blower motor a larger ground wire may help it blow harder. It might be in the thread I linked above: if not, search "Blower motor" and read the threads until you find it.
Problems with the vacuum lines and actuators is why many replace the entire HVAC system with a kit from VintageAir or similar: it's all electric and eliminates vac problems. It's expensive though.
Problems with the vacuum lines and actuators is why many replace the entire HVAC system with a kit from VintageAir or similar: it's all electric and eliminates vac problems. It's expensive though.
