How to fix this Rust on the Firewall?

[JWheeler331]

Anyone have any photos or any info on the best way to handle this rust on the firewall?

I have been doing a little body work here and there but nothing like what this will need. Trying to get some ideas on how others would fix this.

Thanks in advance.

[1963c-10]

Id look for a donar firewall that you can cut up and use.

[PGSigns]

I would say for that you will need another cab for a donor. There are some doublers behind that area for the bolt plates and the spotwelds will have to be cut out. Cut splice and weld in the new sections. Gonna be a big job.
Jimmy

[JWheeler331]

Thank you. I thought it was going to end up being a bigger job than I wanted.

I will keep my eyes open for a doner that I can pick up at an affordable price.

[Lowl!f3]

you could just use some sheet metal a fab that. it wont be stock. but it will be fixed.

[theastronaut]

No need for a donor cab, just cut out each layer and make patches for each layer. I did it on a '65. It's not an easy fix since there's 2-3 layers in places. If your firewall is that bad then you also need to check the seams on the bottom of your cowl, inside the cab. You'll probably have to pull the inner fender mounts as well to get it all out.

[Chevy Fleetside]

Too bad your so far away. I have an extra cab..

[1963c-10]

Originally Posted by Chevy Fleetside

Too bad your so far away. I have an extra cab..

Might be worth the drive for a CA cab.

[JWheeler331]

Originally Posted by theastronaut

No need for a donor cab, just cut out each layer and make patches for each layer. I did it on a '65. It's not an easy fix since there's 2-3 layers in places. If your firewall is that bad then you also need to check the seams on the bottom of your cowl, inside the cab. You'll probably have to pull the inner fender mounts as well to get it all out.

Thank you for the photos. I will dig further into it an see.

Originally Posted by Chevy Fleetside

Too bad your so far away. I have an extra cab..

Just about my luck. Thanks though.

[johnac]

This is what I am doing to a 1969 GMC that has the firewall rusted out along with the ducting inside. This is a necessary issue to be corrected because the heater box begins to separate from the firewall and you will have wet floor and firewall inside the cab anytime you wash your pickup or when it rains.
Also it can let fumes in the cab.
This is a simple yet effective repair that will hold the firewall together. When this area is rusted out there is nothing to support the heater and brake pedal mounting.
The 1" square tubing works very well.
The windshield wiper motor mount will need repaired also.

Youtube videos here:
Part 1: https://youtu.be/nBBQPQAUfX8

[Prflyer1]

IMHO it depends what you are shooting for, I see it as fixable but I am by no means trying to get a show truck, my truck is worse than yours by far and still not going the Cab swap route. As you can see from other posts its completely doable keep us posted as it will help other like me

[Prflyer1]

Originally Posted by johnac

This is what I am doing to a 1969 GMC that has the firewall rusted out along with the ducting inside. This is a necessary issue to be corrected because the heater box begins to separate from the firewall and you will have wet floor and firewall inside the cab anytime you wash your pickup or when it rains.
Also it can let fumes in the cab.
This is a simple yet effective repair that will hold the firewall together. When this area is rusted out there is nothing to support the heater and brake pedal mounting.
The 1" square tubing works very well.
The windshield wiper motor mount will need repaired also.

Youtube videos here:
Part 1: https://youtu.be/nBBQPQAUfX8

Great pics! thanks it helps me too as mine is farther gone

[johnac]

It is going well so far, I have moved to the center section where it is the worst, every thing has separated or disappeared. I have come up with a solution using the part of the square tubing I had cut out.
Once it is complete with the welds smoothed off, sealant applied, and a coat of rattle can paint it will be a clean repair.
Won't look original but this isn't a show or concourse pickup.
Video of Center Repair: https://youtu.be/OEJtv1E3X7k
Play List of Entire Repair to date: https://www.youtube.com/playlist?lis...JX3IJCPpHJcaTp

[Palf70Step]

Nice. I'll have to remember that idea. I always have some C-channel and square tubing around.

[johnac]

I used only square tubing, the pic is of the first piece I cut and the cuts were made on the same side. Later I cut the piece out on 2 sides because I didn't want lip on firewall side but I like the straight bent edge left on the engine side.
The square tubing is nice because the corners aren't heavy like most angle iron and some channel.
You can make a cut off wheel go a long ways if you go back and forth over the cut line until it goes through, if you make the whole cut cutting on the edge of the steel the cut off wheel disappears before your eyes. You can see the groove made in the pic where it hadn't gone through yet.

[johnac]

Nearly Finished, got the center portion looking so-so.
A little paint and it won't look to bad.
Part 4 Video: https://youtu.be/zZCpe9iEEEw
Playlist of repair: https://www.youtube.com/playlist?lis...JX3IJCPpHJcaTp