HVAC Box Repair

[2ndGenGuy]

So I got to work today doing some revamping of the heater box. I have had broken vent doors for so long, and I've been too lazy to pull the dash. The main defrost vent has been broken inside the heater box and the recirc / fresh air flap has been broken on the blower motor too.

Started by pulling the dash.



I also decided to do a couple quick fixes to keep mice and debris out of my car.


Meshed over the fresh air vents.




And the intake for the blower.



I think I might pick up some hypo-allergenic heater filters tomorrow from the hardware store and cut them down to make them into cabin filters. Should help my horrible springtime allergies.

Installed new weather stripping on the new, non-broken blower where it seals up against the fresh air duct.



Also installed new weather stripping around the coupler from the blower to the evaporator. The old stuff was so deteriorated that the blower could just blow air around the evaporator straight into the cabin. Also bypassing the heater...



And here's the new blower motor with functional flap installed.



This is one of the vacuum solenoids that operates the flaps in the box. As you can see one of them was broken, so I'll be replacing it with the good one.


I'm also picking up a new heater core and installing it tomorrow, and as my camera batteries died, I decided to call it a night.

More tomorrow when I swap my good parts from my donor heater box and install the new core.

[Hazwan]

Nice work.

More details on the filter please. I always want to do that, but the gay thing with my 81 is there are no fresh air intake. The system is defaulted to recirculate all the time. I guess they came like that for locally assembled model..

[2ndGenGuy]

Don't your windows fog up all the time when it rains? I bet yours is doing the same thing as my 81, and the flapper is stuck on recirculate. When you put the lever over to defrost, it should automatically move the flap over the blower motor to open...

You've got either an electrical switch that's not working, or the vacuum isn't holding the door open. By default, yes the door is closed, causing it to recirculate.

[Hazwan]

Actually there are no hole at all for the blower to suck air from the outside. Either someone welded it shut or they never have one from the factory. Thats the only thing I still don't understand on my car.

The door mechanism works fine. It doesn't really matter anyway since I always put the AC on 99% of the time, so no fogging on the windows but it would be great to get fresh air from the middle vents.

[2ndGenGuy]

Wow that's weird man. So there's probably not even a door on your blower motor at all. And if you want fresh air, you just flip open the vents?

[Hazwan]

The door mechanism - vacuum solenoid, vacuum pipes, wiring and door is all there, just no hole for the blower to suck air from the outside. Right now I simply flip open the side vents if I wanted fresh air. But it would be nice to have fresh air coming from the center vents. I'm going to cut a hole and install a filter - which I want to see how you do it

[Dr_Snooz]

Looking good man. I'm inspired to tear into my dash now but not until I get a lot of other stuff done.

[Vindicted_Reprise]

how long does it take to pull the dash? it's always been too intimidating to me. there are a lot of things that could use some TLC in my 2gen dash.

[2ndGenGuy]

I started on it about 11am on New Years Day and took my time and worked until about 9pm. I took lunch and dinner breaks and took a trip to the store. It is intimidating at first. It's not HARD its time consuming. And it's a bit tedious. You can't take any shortcuts or nothing will work right when you're done and you've pretty much done all the work for nothing. Just be careful, take your time, and actually dedicate some time to it. Don't have any friends over BSing with you, don't have a TV on, etc. There's just a lot of things to disconnect and you gotta remember where everything goes.

So anyways, I got the box all fixed up and a new heater core installed...



Split the box open to replace the heater core. Which I found out is completely unnecessary. It just slides out of the heater box. DON'T take the box apart if you don't have to. It's a huge PITA to get together.



Since I had it apart, figured I'd lube up all the moving parts. I'm sure it's dried up like an old cooch after 25 years. Remember this car is like 80 years old in human years.


Lubed the temp slider.


And all the little bits.


Installed new weather stripping on the sealing surfaces.


Then finished installing everything nice and tight.

[2ndGenGuy]

Then after the install, I went ahead and installed my cabin filter! I bought a hypoallergenic filter for your house heater. It was about $20.00 compared to the $3.99 ones that looked like the smallest thing they'd filter would be a small dog.



I cut it quite a bit bigger than the vent hole and pushed it in so it fit tight against all the edges. Then put some more weather stripping around the outside just to hold it down in the hole so it doesn't come out for some odd reason...




So that's what I've got for tonight. Hopefully it all works. The job is done aside from reinstalling the dashboard.

[lostforawhile]

how well does it seal against the screen you put up? about to do the same thing.

[2ndGenGuy]

Seems pretty good actually. I figure so long as air can't get around it from the outside, it can only pull air through it. Hopefully it doesn't cut the airflow back too bad. I guess I'll find out tomorrow when I fire it up!

[lostforawhile]

Seems pretty good actually. I figure so long as air can't get around it from the outside, it can only pull air through it. Hopefully it doesn't cut the airflow back too bad. I guess I'll find out tomorrow when I fire it up!

i've taken out my blower about twenty times already, then moved it forward a quarter inch, working on all the stuff under the dash area. still needs to come out one time. i got rid of the evaporator, i made an aluminum plate with a welded on tube that seals the side of thee air box, then another adaptor with a tube that goes into the blower housing. they connect with 3 inch silicone hose. just sick of taking it out and putting it back in. my "new" heater core leaked from day one, but it was over 30 days from the time i bought it.so the warranty was void. i'm buying a used one on here from someone, at least it didn't leak in service, i may have better luck with it. i need to solder a copper fitting on one of the outlet pipes anyway,so i can finish my conversion to AN lines.

[Hazwan]

Nice work.

Just an idea for those who took apart their HVAC box, clean up all those dust and craps while you're at it. The air smells much better with the ducting all cleaned up!

[lostforawhile]

Nice work.

Just an idea for those who took apart their HVAC box, clean up all those dust and craps while you're at it. The air smells much better with the ducting all cleaned up!

yep found a dead mouse in my blower. also if you don't mind the noise get rid of all the padding crap behind the dash. it's old jute material and it absorbs odors like crazy.

[2ndGenGuy]

Yeah if I didn't love A/C so much, I'd have deleted the evaporator too, and just used that silly tube that the non A/C models had. I love the idea of the weight savings, but I also love keeping cool and keeping the windows up, since I have mega spring time allergies. If the 3g and 2g heater cores are the same, you're welcome to one of my two old ones. Mine never leaked, I just replaced it while I had everything out. My luck, the new one will leak, like what happened to you. And supposedly the donor one I got never leaked either. It came out of a SUPER clean car I parted out for someone.

I should have taken pics before I ripped that thing apart...

[2ndGenGuy]

Nice work.

Just an idea for those who took apart their HVAC box, clean up all those dust and craps while you're at it. The air smells much better with the ducting all cleaned up!

+1. I blew out everything with a compressor and wiped down every surface I could with a clean rag.

[2ndGenGuy]

yep found a dead mouse in my blower. also if you don't mind the noise get rid of all the padding crap behind the dash. it's old jute material and it absorbs odors like crazy.

Exactly why I put that mesh in, to keep those little bastards out.

I thought about pulling that jute out. But it's so thick... I'm afraid it will be ridiculously loud... I could still pull it out easily enough. I suppose.

[lostforawhile]

Exactly why I put that mesh in, to keep those little bastards out.

I thought about pulling that jute out. But it's so thick... I'm afraid it will be ridiculously loud... I could still pull it out easily enough. I suppose.

I took a whiff of that jute crap, and it reeked,thats why junkyard cars smell so bad too. what year is yours? i will try and cross reference the two heater cores. the jute insulation under the carpet was so bad it had actually stuck to the floor.

[lostforawhile]

oh if yours is built like the three g, how mice get in there, there are two rubber flappers over the drains inside of the cowl area,one on each end, they simply climb up the drains and chew through the flappers. if you have those,put a piece of screen over each one inside of the cowl.

[2ndGenGuy]

Mine is an 84.

[Vindicted_Reprise]

that jute crap, it sucks, it gets all soggy if you ever have a leak, and it doesn't dry out so well. i really want to pull all of mine and then get dynamat for the road and engine noise. but that stuff is expensive, at least where i have seen it. i'm also thinking about using it in my trunk for better sub resonance. let us know how the air flow is with that hepa filter in the blower intake. it's really exciting that someone's getting on this! i have serious allergies too.

[lostforawhile]

if that filter is too restrictive get a hepa filter for a shop vac. they are designed to allow a lot of air to pass through them and still filter.

[Dr_Snooz]

Nice work.

Just an idea for those who took apart their HVAC box, clean up all those dust and craps while you're at it. The air smells much better with the ducting all cleaned up!

I soooo need to do this! My vents stick like old decomposing plastic. I shoot them with Vinylex or Pledge every so often and it kills the smell until the next sunny day when it all starts stinking again. I suspect the jute is making some bad smells too.

This thread is AWESOME! Thanks!

[lostforawhile]

here's a link on the hamb about cheap alternatives to that insulation,some great ideas on here. http://www.jalopyjournal.com/forum/s...ad.php?t=51399