replacing plenum to replace duct hose to drivers side windshield..advice?

[hummer4x4guy]

Here is what I am working on next. The air duct going to the drivers side windshield is SHOT! IT has holes all through it.
I have the new one here but I am having an issue getting the screws that hold the plenum on that goes between the drivers and passengers side (directly under the windshield). I have a new plenum now ordered but I am looking to see if anyone else has had to remove theirs and if you also had all the screws rusted solid. If I break off the screw heads with a chisel would I be able to eventually remove that piece or do you believe the screws will be stuck still in the aluminum part of the truck that would not be replaced?
I can pretty much get a hacksaw in between the plenum and the part just below it and saw the screws in half, if I ruin the old piece thats not a problem but id like to try not to.
Any thoughts?

 

[Retiredwarhorses]

You have no real choices....either heat the screws up and try to get them loose, or grind them down.
the problem is that those really tiny ones tap right into the aluminum A-pillar, in turn the screws are steel, so they have a wonderful time welding themselves together over time. The larger screws are a pan head wood screw, those actually screw into the A Beam vent covers flat captive nuts...metal as well, but easier to get loose as the head is larger....

 

[glassk]

I have not seen the part you are talking about, but sound like a blind stud of some type.

I have some of these , no tools to install them though if you might like to try,

 

[Retiredwarhorses]

I have not seen the part you are talking about, but sound like a blind stud of some type.

I have some of these , no tools to install them though if you might like to try,

his issue is getting the old out, not the new in....

as I stated....the access panel under the A-pillar is secured with self tapping screws....4 really small ones and 6 or so larger ones. It's just a cover plate for the air plenum and access the wire harness for wiper connectors in the Windshield frame.

 

[glassk]

his issue is getting the old out, not the new in....

as I stated....the access panel under the A-pillar is secured with self tapping screws....4 really small ones and 6 or so larger ones. It's just a cover plate for the air plenum and access the wire harness for wiper connectors in the Windshield frame.

Thanks, didn't pick up on that, at the risk of highjacking this thread, do any of the parts in photo look familiar , I have some and have not been able to find end item info,


If you have some ATF and acetone you can make a 50/50 mix and put a few drops on the screw to break the bond between the steel and aluminum


...

 

[Retiredwarhorses]

The screws are upside down and captive....i run this issue on 9 outa 10 trucks....heat them And try to break them loose...then if that dont work, grind the heads off and drill them out...abandon the small ones, they are not needed

 

[Retiredwarhorses]