I have seaarched and posted this in the past, but I though tI had the problems solved. I have an '80 Bronco Custom with the 5.8.It has a non- functioning AC.

It was a rust bucket but sound mechanically and over the years have done extensive body work. In the early days, before I did the body work, i woudl drive down a gravel road and the dust would roll into the Bronco from an unseen source. I was never able to figure out where it was coming from.

At first I thought it might be openings in the firewall where wires and hoses passed through. I sealed all those. Then it was suggested that maybe dust was coming through the rusted out fender wells into the cab.

So, as I drive down the country roads at times, I can see a haze of dust floating about in the cab and settling over everything. Other times, no dust. I have never had this problem in any truck I have owned. The only way I seem to be able to control it to leave the windows up and turn on the AC to Max. Remember, the AC doesn't work, so I am theorizing this pressurizes the cab and keeps out the dust. Trouble is, when it is 90+ degrees out, the cab quickly become an oven. Not an option in southern Illinois in summer!

One wag suggested that if I don't want the dust to come in, don't roll down the windows on a gravel road.Duh! The dust DOESN'T come in the windows! It will even roll in if the windows are up and the blower isn't running.

Any fresh suggestions? I have looked for areas when the buildup of dust woudl suggest where it is entering but have found nothing conclusive.

Since I hunt, hike and fish in area where 90% of the roads are gravel, this makes for an unpleasant experience. I am considering selling the Bronc just for this annoying reason.

 

Just a thought (and I am not as familiar with the older models) but does your '80 have manual vents down near the floor or along the kick panels on the driver's and passengers side under the dashboard. I know a lot of older vehicles had small hand-operated vents that could be opened to let fresh air in. Could be that either the hanldes are missing or the vents are stuck open. Again, this is only speculation but I know the older Ford vans had these vents in them. Perhaps the F-series and Broncos did too.

 

When you put the AC switch to "max AC" it should be in a recirculate mode, and it should not let in any air from the outside. On any other setting it will pull in air from the cowl just below and in front of the windshield. On a few "cars" I have had.....Volvo, BMW......they have a cabin air filter to filter out dust and even pollen down to some asinine micron number. I would think if you remove the cowl and improvise some sort of filter to keep the dust from getting into the fresh air intake, it may help. I dont know how easy this will be and as I said it *may* help?????

 

My 1990 bronco has been doing this recently. The dust is coming in somewhere around the rear tailgate area on mine. I think it might be caused by old weatherstripping. I tried cleaning the weatherstripping and then I sprayed it with silicone and it didn't help a thing. It's really annoying when it happens.

 

My 88 has clear plastic sheets (like heavy duty clear plastic drop cloths) under both door panels and under the access panel of the tailgate. I assume it is to keep out dust. I previously replaced them when they went bad.

 

Good thoughts, guys. Thanks.

In reply to greystreak92--to whom I congratulate on the fine job you did on the Bronco FAQ!--my Bronc doesn't have the manula vents. However,on the interior firewall on the passenger side is an opening with a grate over it. I assume this is something to do with the recirclation system. Every fall I have to vacuum the accumulation of leaves and other trash that collects in this area.

 

i have found putting the ac to max or defrost to max it keeps enough pressure in the cab to hold out any dust coming in from worn weatherstripping

 

tombob,

Thanks on the FAQ feedback and to the problem you are dealing with, now that its been mentioned, I too have seen dust and general crud levels increase in the truck if tailgate seals and rear window seal are bad. The dead air vortex behind the truck while its travelling sucks everthing against the rear window and the tailgate. Hence the reason our rear windows get so dirty so quickly and rear exiting the exhaust is such a bad idea. I even had problems with increased dirt levels with the inspection cover removed from the tailgate because dust was coming in through the DRAIN HOLES in the tailgate!

 

I HAVE THE SAME ISSUE LOOK UNDER THE DASH PASSANGER SIDE AND REMOVE THE PASSENGER KICK PANEL THINK LEAK IS HERE AND MAYBE IN THE HEAT AND AIR VENT SYSTEM I AM TEARING MINE DOWN SOON PLEASE POST IF YOU FIND SOMETHING BEST LUCK ... THERIN

 

VENT YOUR EXHAUST OUT THE SIDES BEHIND THE REAL WHEEL AND BOOM NO EXHAUST SMELL <3