Removing Evap/Heat Box from 1970 300--What's blocking it?

Trace 300 Hurst

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I'm pulling my box out to rebuild it, and I **almost** have it out. I have the right side far enough back that the core nipples are clear of the firewall, but the left side of the box won't "roll out and down and remove" like the FSM so matter-of-factly states. The studs on the left side are still about 3/8ths into the engine compartment, so I'm a long way from "roll it out".

I also have the engine-side housing completely loose and the fan is removed (and the inner fender is removed, of course, so I'm in deep).

Is there a trick? Is it the radio? Or....is it that thick bundle of cables that's just to the right of the radio. That bundle is held quite securely by those bendable tabs, but they're heavy duty.

I'm tired of dust and mouse poop in my eyes and hair....grrrrrr.
 
I took the dash out to take mine out... Not what you want to hear, I'm sure.

But... Thinking about it, (Which is always dangerous) it's easy to unbolt the top, loosen the bottom bolts and roll the dash towards you. You shouldn't have to unhook anything, but that's an edumicated guess at best. That might give you enough clearance to get at it. One other thing I've discovered is the radio and ashtrays need to come out every time you try to do anything with the dash.
 
Thanks, John.

I'm planning to put the panel, but not wanting to pull the difficult dash. I know you're the Dash Man and have those difficulties licked.

Radio and left ashtray are out. It's clearly that thumb-thick wire bundle that runs on that vertical dash brace just to the right of the radio, and immediately behind the left corner of the box, right near the defrost door pot. That bundle is REALLY held in place by the heavy-duty tangs, which won't allow you to spread them because the box is in the way. It's a standoff!

I have the lower tang bent out of the way, but the next one up, with no room to work, is vexing me. I may break out the Dremel to cut it away, and that should....maybe...allow me to move the bundle to the left and "roll the box out".

They make sound sooooooo simple. I can hear the Service Manager at my dealership in 1976 saying "You're not gonna make any money on that job. The book time is 1.5 hours." :mad:

So, I guess I'm asking that if there's nothing keeping it from rolling out (including the vent cable, removed from passenger side vent door), it DOES come out?
 
If it makes you feel any better... The blend door motor is shot in my Grand Marquis. The procedure calls for removing the dash. I think I can just unbolt one side according to those who have done the job.
 
You should see the workaround that I did on my 2013 Vette last week regarding the blend door actuator (a common failure). Step One says Remove the Whole Damn Dash so you can Remove the Whole Damn Evap Box, which is a monster undertaking.

The two little actuator screws that hold the actuator in place are on the other side of a big aluminum structure for dash/airbag mounting. Impossible to get to to remove this $33 actuator. Impossible.

Unless you figure out where to fire up the Step-Bit in two places opposite those screws. 15 minutes later, the new actuator is in place. Why didn't GM put holes there in the first place. Grrrrrr...

BEFORE

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AFTER

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Yeah, It Just Rolls Out. Once you get all the things out of the way that's behind it.

The piece of metal laying in front of the box is one of the wire bundle tangs that could not be bent out of the way because it was against the defrost duct. Mr. Dremel made short work of it, and I could then maneuver the bundle out of the way and......and roll the box out. Sorta. It catches on everyfrigginthing on the way out. Should be a joy to reinstall.

So twice in one week I've cut into the structures of dashboards to get an AC repairs. It's a trend!

IMG_1032.JPG

Everything looks solid. This was a NM and TX car its whole life, and it's FILLED with fine red/brown dust...which is better than red/brown rust! Bueno.
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Very old mouse scat. And the nest I found behind the glove box.

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Mouse nest.JPG
 
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Seems just as well you removed it, get it sorted then reinstall happy that all the !@#$ has been removed.

Randy and his staff pulled the dash out of Lee- doc's new 73 imperial to get it all sorted, quite a job I believe, but at least any/all concerns have been fixed.

Happy motoring when yours is back on the highway.
 
Cars, especially GMs, were designed to be built, not worked on, by observation. When Chrysler did the fuselage cars, it seemed that compared to the Slabs, they'd hired some GM engineers to design them. Blower motor now hidden behind a fender well, ala GM, for example.

When you know how they were put together (with completed sub-assemblies done "off-line" at the plant), then you can probably figure out how to better understand how to work on them. Which can mean unbolting and removing the complete instrument panel rather than trying to work on it "in car", for example. But that particular item usually is not a one-person job, requiring another person to help, plus removing the front seat(s) and such.

Thanks for the tips!!!

CBODY67
 
One thing I saw in your pic of the removed heater box is the foam seals have deteriorated or missing. Should look like this. With all the seals replaced your heater and a/c will work much better. Foam seals can be bought from Detroit Muscle Technologies.

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20190214_205307.jpg
 
One thing I saw in your pic of the removed heater box is the foam seals have deteriorated or missing. Foam seals can be bought from Detroit Muscle Technologies

David,

Thank you , and you are correct, sir. My foam seals turned to rubber dust a LONG time ago. And yes, I have the full Detroit Muscle kit, plus the shoddy pad kit to replace that used for mouse nest materials. Plus the DetMusc splash shield kit, which is the absolute tits. Perfect stuff.

And that's why I've pulled this box. Full rebuild, test the vacuum pots, inspect the hoses, inspect for rodent chewing (they liked the antenna cable...tasty!), clean the evap internally and in the fins (along with a total redo of rest of the R12 side of things [I have 19 lbs of it]), new vacuum switch, new blower switch, new fan motor, solder/blank-off any barnacles or suspicious tubes in the heater core, reuse the old good blower resistor, rebuild the recirc door assembly.....a total redo of the HVAC. This is all simultaneous with a total redo of the instrument panel. Lights, switches, voltage limiter, printed circuit board, etc.

I don't mess around with half-measures. But I can still drive it to my storage unit nearby with all of the dash stuff missing! It's windy with the AC box and engine side cover missing, but I'm in Florida. I can use the cool air.
 
Cars, especially GMs, were designed to be built, not worked on, by observation. When Chrysler did the fuselage cars, it seemed that compared to the Slabs, they'd hired some GM engineers to design them. Blower motor now hidden behind a fender well, ala GM, for example.

When you know how they were put together (with completed sub-assemblies done "off-line" at the plant), then you can probably figure out how to better understand how to work on them. Which can mean unbolting and removing the complete instrument panel rather than trying to work on it "in car", for example. But that particular item usually is not a one-person job, requiring another person to help, plus removing the front seat(s) and such.

Thanks for the tips!!!

CBODY67

Agreed with your general point of working the sub-assemblies as a unit as was done when the car was built, but the issue is one of fragility. Everything in these dash assemblies (cosmetic and behind-the-scenes functional stuff) is subject to acute and rapid cracking and crumbling during disassembly. Or worse yet, have your forearms on the glove box door while you're wrestling with the HVAC box. CRACK!

I remove that delicate stuff FIRST.

The funny thing about my blower motor hiding inside the fenderwell--that was easy. Unscrew the few things bolted to the fenderwell and move out of the way, remove fenderwell bolts with an air rachet.....down it comes in 20 minutes. Blower is another 4 minutes to remove.

But not that damn Evap box! *****!

And my Vette fix was a stunning victory. I put that off for a month, dreading disassembling my entire car just to get Blend Door/Mode Door functionality back. I think I owe $500 to whoever invented the Step-Bit.
 
David,

Thank you , and you are correct, sir. My foam seals turned to rubber dust a LONG time ago. And yes, I have the full Detroit Muscle kit, plus the shoddy pad kit to replace that used for mouse nest materials. Plus the DetMusc splash shield kit, which is the absolute tits. Perfect stuff.

And that's why I've pulled this box. Full rebuild, test the vacuum pots, inspect the hoses, inspect for rodent chewing (they liked the antenna cable...tasty!), clean the evap internally and in the fins (along with a total redo of rest of the R12 side of things [I have 19 lbs of it]), new vacuum switch, new blower switch, new fan motor, solder/blank-off any barnacles or suspicious tubes in the heater core, reuse the old good blower resistor, rebuild the recirc door assembly.....a total redo of the HVAC. This is all simultaneous with a total redo of the instrument panel. Lights, switches, voltage limiter, printed circuit board, etc.

I don't mess around with half-measures. But I can still drive it to my storage unit nearby with all of the dash stuff missing! It's windy with the AC box and engine side cover missing, but I'm in Florida. I can use the cool air.
As an afterthought have your evaporator professionally tested. Small leaks can be missed. With that much age on the original unit it couldn't hurt. Sounds like you have done this before. If you run into any trouble, PM me
 
There was dye in the system, so I'm hoping that after careful scrutiny I can check eliminate that issue, but you're right that if there's a hint of trouble or corrosion (mouse pee on aluminum!) I'll have it tested.

When I got the car the system was empty, although it had been converted to 134 at some point. I put in a few lbs and it held for months before I took it all apart recently (new RV2, exp valve, flushing all lines and cond/evap when out of the car, dryer, etc) so again, hopefully, the two cores in there are okay. The has been no coolant smell, even with the car getting real hot last summer before I went to a new radiator/stat/hoses and refreshed the whole system. We'll see when I get that core apart this weekend.
 
Just wanted to finish this discussion. Got everything clean and rebuilt, wrestled the box back under the dash (eat your Wheaties or get some help. I ate four boxes!). Got the engine-side housing on, and fyi getting to the nuts behind the engine is a PITA. New blower, lots of new parts everywhere, wheel housing back in...then a rebuild of the instrument panel with all new HVAC controls, etc. It all blows neat and clean, box doors work perfectly, and no mouse turds or other 48 year old debris in the airstream. Ugh!
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Mouse turds and pee! All gone now. Soaked all box components in a tub of Top Job and some bleach.
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Ready for re-installation!
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Now it's time to get the R-12 side of things back together (new compressor with PAG oil removed, mineral oil in there now, plus UV leak detect stuff), new Receiver, pressure cutout, new expansion valve, line seals, (including PN 3441513 o-ring on the discharge side of the compressor vs the aftermarket paper gaskets). And yes, everything has been flushed with the compressed air flush kit, using FOUR 16 oz bottles for the components while they were off the car. Evap, condenser, and lines run clear of all previous oil and leak colorant. I'm using the OEM EPR valve with the R-12, of course. It's essentially a total rebuild of the factory system. No Sanden for me.


I'll swing back to this thread when I'b blowing ice cubes in a week.
 
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