E-Bodies.org Cuda Challenger Forum

Technical Shop => Body Shop => Topic started by: nicka on August 19, 2020, 08:16:16 AM

Title: Firewall Repair or Replace
Post by: nicka on August 19, 2020, 08:16:16 AM
I'm looking at a lot of rust and holes all along the firewall that resides underneath the cowl area.  The lower area of the firewall looks ok. I think patching the rust holes is out of the question due to the rust and holes all along the length of the firewall.  So looks like I'll have to order a new AMD firewall. 
Has anyone removed just the old upper firewall area and replaced it with a new sectioned piece? Cut the old metal just above the lower cowl and lap weld it from the inside ? The floor is out of the car.

Title: Re: Firewall Repair or Replace
Post by: Rich G. on August 19, 2020, 02:05:16 PM
At this point I'd replace the whole thing. You already got the floor out by the time you cut it off the lower cowl who knows what will be left to even weld to. I replaced the whole cowl on my cuda and it wasn't that bad considering it was a lot of work.
Title: Re: Firewall Repair or Replace
Post by: Dmod1974 on August 19, 2020, 03:30:14 PM
I replaced my firewall and cowl with AMD.  If you go that route, absolutely mock up the pedals, column, and dash before you paint or go back together.  My firewall bracket was way off and I had to remove and reweld it.  Luckily, I'm still in the metal work phase but it would have been really bad if I hadn't taken the time to mock up everything.

Also check your wiper cowl trim fit.  I had to slot the holes slightly on mine.  Basically, test fit EVERYTHING and don't be surprised if you find things off.  I also sealed the cowl vent areas heavily with seam sealer since I don't see how they could be water tight without it.
Title: Re: Firewall Repair or Replace
Post by: jimynick on August 20, 2020, 07:43:19 PM
Quote from: Dmod1974 on August 19, 2020, 03:30:14 PM
I replaced my firewall and cowl with AMD.  If you go that route, absolutely mock up the pedals, column, and dash before you paint or go back together.  My firewall bracket was way off and I had to remove and reweld it.  Luckily, I'm still in the metal work phase but it would have been really bad if I hadn't taken the time to mock up everything.

Also check your wiper cowl trim fit.  I had to slot the holes slightly on mine.  Basically, test fit EVERYTHING and don't be surprised if you find things off.  I also sealed the cowl vent areas heavily with seam sealer since I don't see how they could be water tight without it.
While I, too, replaced the whole cowl/firewall/frt floor panels I had no misery regarding bracketry nor holes. What we did, was we bonded the cowl to the firewall before installing the assbly in and tying it into the new floor panel. There we did have to screw around a bit and had a 4X4 on a floor jack into the trans tunnel to help align the firewall/floor flanges. Buy yourself a few more vice-grips or Clecos when you do it. You'll thank me later. take your time, measure and re-measure and then measure again and weld once. You've got this.  :cheers:
PS- the bonding kits make a helluva sealant too!
Title: Re: Firewall Repair or Replace
Post by: RUNCHARGER on August 20, 2020, 07:51:31 PM
The bonding works awesome on 4 speed humps as well.
Title: Re: Firewall Repair or Replace
Post by: nicka on August 21, 2020, 07:01:45 AM
I called AMD and the firewall with a/c have been discontinued for over a year.  Ouch.  Time to check other vendors.

Title: Re: Firewall Repair or Replace
Post by: nicka on August 21, 2020, 07:31:45 AM
When I purchased the car,  the previous owner stripped out the a/c components except the blower box which means I have to start all over.  Since this car is not a numbers matching car, maybe I should purchase the non a/c firewall and purchase the latest a/c units?  I heard the latest a/c units are a lot better like Classic Air.  Worst case scenario would be to get the non a/c firewall and cut out and replace the a/c portion of the firewall.

Title: Re: Firewall Repair or Replace
Post by: nicka on August 21, 2020, 07:55:23 AM
I just got off the phone with Classic Air and to use their complete system, they only need the heater hose so the non a/c firewall will work.  All good points to purchase the non a/c firewall.

Title: Re: Firewall Repair or Replace
Post by: RacerX on August 21, 2020, 07:58:38 AM
Quote from: nicka on August 21, 2020, 07:31:45 AM
When I purchased the car,  the previous owner stripped out the a/c components except the blower box which means I have to start all over.  Since this car is not a numbers matching car, maybe I should purchase the non a/c firewall and purchase the latest a/c units?  I heard the latest a/c units are a lot better like Classic Air.  Worst case scenario would be to get the non a/c firewall and cut out and replace the a/c portion of the firewall.


I am in the same situation with my 71 cuda...  the cowl and firewall have a lot of rust and
at first I was considering it an opportunity to add factory air by using the A/C firewall.  But
after looking closely at the Vintage Air system I decided to just use the non-A/C firewall and
run their system.    It is not necessary to have an A/C firewall for their system, and inside the
car it looks factory stock, except for the little blue light at the switch panel.   

The only factory A/C parts you need with their system is the dash vents.   They have their
own aftermarket vents if you have a non-A/C car but I like that it can tie into the factory
vents and appear stock.


Title: Re: Firewall Repair or Replace
Post by: nicka on August 21, 2020, 11:36:43 AM
My 71 barracuda originally came with an a/c so I have the original vents.  I spoke with Classic Air and their kits allow to hook up with the original vents or their own.  I heard the newer ac units are more efficient. Also, I picked up a Shaker hood while at Carlisle and the Classic Air uses the Sanden compressor.
Title: Re: Firewall Repair or Replace
Post by: RacerX on August 21, 2020, 12:17:06 PM
Quote from: nicka on August 21, 2020, 11:36:43 AM
My 71 barracuda originally came with an a/c so I have the original vents.  I spoke with Classic Air and their kits allow to hook up with the original vents or their own.  I heard the newer ac units are more efficient. Also, I picked up a Shaker hood while at Carlisle and the Classic Air uses the Sanden compressor.

I like the Vintage Air setup for the more "refined" look of the interior parts, but either vendor will do the job with nice, new, modern components.
Title: Re: Firewall Repair or Replace
Post by: nicka on August 21, 2020, 12:19:46 PM
I guess another option would be restore the a/c heater box and cut out that area of the firewall and weld it onto a new firewall and order remaining new a/c parts.

Title: Re: Firewall Repair or Replace
Post by: Rich G. on August 21, 2020, 12:32:09 PM
Boy it seems like AMD is getting out of the E Body business!  That's disappointing for the hobby considering the only project cars left are rust buckets!
Title: Re: Firewall Repair or Replace
Post by: RUNCHARGER on August 21, 2020, 08:01:05 PM
AMD is going all out in GM and Ford stuff now.
Title: Re: Firewall Repair or Replace
Post by: nicka on August 25, 2020, 06:14:59 PM
The firewall is out.  I like the idea of panel bond.  Wonder if they make a panel bond that matches the color of the original sealer?  Mocking up is a good idea.  I'm thinking about painting underneath the cowl area before panel bond.  Thinking about keeping the original a/c heater box.  I found two vendors that sell rebuild kits.  Looks like Classic Auto Air will hook up to an original a/c heater box.
Title: Re: Firewall Repair or Replace
Post by: nicka on September 10, 2020, 02:34:06 PM
So the AMD firewall for my '71 Barracuda showed up today.  Had a chance to compare the old and new and I see at least 7 differences.  Note, they no longer produce the a/c version so I ordered the non a/c version.


Title: Re: Firewall Repair or Replace
Post by: anlauto on September 10, 2020, 04:28:39 PM
If you're worried about the "little things" swap out all the little brackets that hold the brake line and wire harness...I always do....that and even the weld nuts for the steering column  :alan2cents:
Title: Re: Firewall Repair or Replace
Post by: nicka on September 10, 2020, 05:04:40 PM
What's that large  7 inch "stove pipe" on top drivers side used for?  I've got the original a/c heater box and thought about maybe reusing it.  The blower motor, drain hose, and a/c vacuum drain holes are in a different location.  The evaporator and heater core holes are different.  The column tabs look different.  Mine has a horizontal crease along the center.   I'm starting to lean on keeping the original lower half and replace the rusted out piece above the cowl. 
Title: Re: Firewall Repair or Replace
Post by: 70 Challenger Lover on September 10, 2020, 05:13:00 PM
There is a guy in Az selling a new AMD upper and lower cowl set dirt cheap and it's for A/C. Not sure where you are but if it's close, I'd buy it and resell the non AC one if that is what you really want.
Title: Re: Firewall Repair or Replace
Post by: anlauto on September 10, 2020, 06:16:09 PM
You purchased a non-AC firewall of course they're totally different, I thought you were getting rid of the AC and that's why you purchased it.... :dunno:

It's a lot of extra work to convert it....The driver's side "stove pipe" is for the driver's side vent box, something AC cars don't have. :alan2cents:
Title: Re: Firewall Repair or Replace
Post by: RacerX on September 10, 2020, 06:18:33 PM
Quote from: nicka on September 10, 2020, 05:04:40 PM
What's that large  7 inch "stove pipe" on top drivers side used for?  I've got the original a/c heater box and thought about maybe reusing it.  The blower motor, drain hose, and a/c vacuum drain holes are in a different location.  The evaporator and heater core holes are different.  The column tabs look different.  Mine has a horizontal crease along the center.   I'm starting to lean on keeping the original lower half and replace the rusted out piece above the cowl.

The stove pipe on the driver side is for the air vent.   Non A/C cars get two cable operated air vents.

I think it goes without saying that the heater box would be different between A/C and non A/C.  There is no part of your A/C heater box that will swap.  You will need to source a non-A/C heater box and the driver side vent box.   

In your case I would try to get the A/C firewall...   if that one mentioned above doesn't pan out try Classic Muscle Metal in Georgia...  they are in tight with AMD may have the A/C firewall at their shop.






Title: Re: Firewall Repair or Replace
Post by: anlauto on September 10, 2020, 06:28:55 PM
Classic Industries has an AC Firewall in stock  :dunno:

Roseville shows them too https://www.rosevillemoparts.com/product/firewall-70-74-e-body-w_-a_c/
Title: Re: Firewall Repair or Replace
Post by: RacerX on September 10, 2020, 07:01:33 PM
Quote from: anlauto on September 10, 2020, 06:28:55 PM
Classic Industries has an AC Firewall in stock  :dunno:

Roseville shows them too https://www.rosevillemoparts.com/product/firewall-70-74-e-body-w_-a_c/

I figured he had already tried the "go-to" guys first...

Roseville does show it as available, but do they stock large sheet metal pieces at their shop?   I thought it was all drop ship from AMD for them?

Title: Re: Firewall Repair or Replace
Post by: Mopar5 on September 10, 2020, 09:24:52 PM
If im reading it correctly it looks like you get the AC firewall and cowl all welded together as one unit from classic,for $699.00. seems like a good deal.
Title: Re: Firewall Repair or Replace
Post by: Cuda416 on September 11, 2020, 04:37:24 AM
Is there a difference between a Challenger and a Cuda firewall? No one talks about Dynacorn it seems.

http://dynacorndepot.com/firewall-70-74-challenger-6070-challenger-70-74

Something wrong with these?
Title: Re: Firewall Repair or Replace
Post by: anlauto on September 11, 2020, 05:10:37 AM
No difference in the Cuda vs Challenger firewall. I think that one is the one Classic Industries sells, that or Goodmark.. :thinking:
Title: Re: Firewall Repair or Replace
Post by: nicka on September 11, 2020, 08:37:21 AM
Thanks all for the comments.  I'm on the fence of whether to stay original or purchase a complete modern kit.  First, I'm going to look and see if I have all the a/c parts and pieces that were under the dash and see if they are in good working order.  If I'm not missing any pieces and everything is in good working order, I will look at the condition of the original box.  If I run into any hiccups, I have the new firewall so I can move to a more modern system. 

Thanks again.
Title: Re: Firewall Repair or Replace
Post by: Cuda416 on September 11, 2020, 09:36:07 AM
Quote from: anlauto on September 11, 2020, 05:10:37 AM
No difference in the Cuda vs Challenger firewall. I think that one is the one Classic Industries sells, that or Goodmark.. :thinking:

Ok, I thought they were the same.

On the maker of that firewall in the link, I thought dynacorn made all of there own stuff, no?
Title: Re: Firewall Repair or Replace
Post by: RacerX on September 11, 2020, 12:47:49 PM
Quote from: nicka on September 11, 2020, 08:37:21 AM
Thanks all for the comments.  I'm on the fence of whether to stay original or purchase a complete modern kit.  First, I'm going to look and see if I have all the a/c parts and pieces that were under the dash and see if they are in good working order.  If I'm not missing any pieces and everything is in good working order, I will look at the condition of the original box.  If I run into any hiccups, I have the new firewall so I can move to a more modern system. 

Thanks again.

Oh yea I forgot you were considering the classic/vintage air A/C system...   in that case, you are OK.   You don't need any of the factory A/C stuff except for the dash vents.    The modern systems include a new heater/AC box.   You will still need the vent box for the driver's side or just weld a cover over the big hole in the firewall.