Dealing with frame rot

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Dr C GT

Dr C GT

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Hey all, looking for some advice.

I have a small section of frame rot that I am debating how to deal with it. It is about about the size of a business card on both the exterior and lower surfaces on the driver's side just behind the front wheel. (I don't have a picture currently, but I can get one.)

Would it be better to cut out the small section and weld in place a new piece of steel or go with one of those repair caps (1960-1976 Dodge Dart Parts | MM8154 | 1960-76 Mopar A-Body Front Frame Rail Repair Cap (Front Section); LH | Classic Industries

It would certainly be cheaper to go with a small section of steel, and the repair cap seems overkill for the size of the problem spot.

I would appreciate your thoughts, advice, previous experience.

TIA
 
Cut it out and replace it. Covering it with a frame cap is just delaying the inevitable, you’ll trap rust in there between the layers and it will fail again.

Plan on replacing at least twice as much metal as it looks like you’ll need to from the outside. Once you cut into it I guarantee you’ll find the damage is more extensive than it appears.
 
Look closer. A lot closer. The rails rust from the inside out. Don't be surprised if the remaining metal is paper thin. Also check the torsion bar crossmember around the large t-bar sockets. BTDT.

I bought a rust-free complete front clip that included the rails, rad support, inner fenders and t-bar crossmember and welded it in.

Ahhh...the joys of living in the rust belt.
 
I'm sure the rust is more extensive, but the easily visible spots are below.

Pics for reference:
Outside
IMG_20181116_165232.jpg


Underside
IMG_20181116_165242.jpg
 
Dr C GT said:
I'm sure the rust is more extensive, but the easily visible spots are below.

Pics for reference:
Outside
View attachment 1715249989

Underside
View attachment 1715249990
Click to expand...

Start looking for a replacement frame rail. You're going to have to replace 90% of the frame rail visible in the lower picture to do it right. There's very little metal in that bottom picture that you'll be able to weld to successfully.

I would also be very suspicious of the other rail and the torsion bar crossmember based on the condition of that rail.
 
I had the same rot in my Duster, it was cause by old wiper piviot seals, which leaked and filled the floor with water.
When the floor rotted out, water went in the frame rail.

Find the cause of the rot.

Mine was worse than yours, but I patched it with a cap, after cleaning everything up.
P.S. the caps do not fit worth a crap, be prepared to bend it to fit.

People who do not live in the rust belt, are scared of a little rust, it is just expected here.
That frame rail from the pic, does not look that bad, but inspect the full rail, tap on it with a hammer.
 
sireland67 said:
I had the same rot in my Duster, it was cause by old wiper piviot seals, which leaked and filled the floor with water.
When the floor rotted out, water went in the frame rail.

Find the cause of the rot.

Mine was worse than yours, but I patched it with a cap, after cleaning everything up.
P.S. the caps do not fit worth a crap, be prepared to bend it to fit.

People who do not live in the rust belt, are scared of a little rust, it is just expected here.
That frame rail from the pic, does not look that bad, but inspect the full rail, tap on it with a hammer.
Click to expand...
I agree, the caps don't fit.
 
sireland67 said:
I had the same rot in my Duster, it was cause by old wiper piviot seals, which leaked and filled the floor with water.
When the floor rotted out, water went in the frame rail.

Find the cause of the rot.
Click to expand...

The floors are rotted out as well. You can actually see the white patch panel in the lower picture. So I know they need replaced. I'm wondering the source of the water intrusion.

I've only had the car 6 days, so I haven't had the opportunity to do an in depth inspection. In your opinions, does it appear that the frame is structurally unsafe? As a teacher, I was hoping that I wouldn't have to park the Dart until I get time to extensively work on it next summer. I only commute 1.5 miles round trip each day and was anticipating it to be my daily in the meantime.
 
sireland67 said:
I had the same rot in my Duster, it was cause by old wiper piviot seals, which leaked and filled the floor with water.
When the floor rotted out, water went in the frame rail.

Find the cause of the rot.

Mine was worse than yours, but I patched it with a cap, after cleaning everything up.
P.S. the caps do not fit worth a crap, be prepared to bend it to fit.

People who do not live in the rust belt, are scared of a little rust, it is just expected here.
That frame rail from the pic, does not look that bad, but inspect the full rail, tap on it with a hammer.
Click to expand...

Not scared of rust at all, when I'm done with my Challenger I'll have replaced most of 3 frame rails, both quarters, most of the floor, half the firewall, half the roof structure and the roof skin.

The majority of the rail in that picture will have to be removed and "patched". But that's going to be at least a 3 sided patch that's a good 8" or more long.

That's the problem with buying cars from people in the rust belt. "not that bad" means a frame rail replacement, "has some rust" means you're building a new car from the AMD catalog, and "rough" means you can't even recycle the scrap because it's all oxide.

Dr C GT said:
The floors are rotted out as well. You can actually see the white patch panel in the lower picture. So I know they need replaced. I'm wondering the source of the water intrusion.

I've only had the car 6 days, so I haven't had the opportunity to do an in depth inspection. In your opinions, does it appear that the frame is structurally unsafe? As a teacher, I was hoping that I wouldn't have to park the Dart until I get time to extensively work on it next summer. I only commute 1.5 miles round trip each day and was anticipating it to be my daily in the meantime.
Click to expand...

That rail is not structurally safe as it is in my opinion. There's very little strength there, and that's right where it ties in to the end of the rocker panel.

Also worth noting, a unibody with significant floor pan damage is not structurally safe either, because the floor pan is a significant structural component. That section of floor pan is GONE, so, just on that the car isn't what I would consider structurally sound. The combination of the floor damage and the frame rail damage makes it a no-brainer, that's not a car you should be driving regularly, if at all.
 
72bluNblu said:
The majority of the rail in that picture will have to be removed and "patched". But that's going to be at least a 3 sided patch that's a good 8" or more long.

That rail is not structurally safe as it is in my opinion. There's very little strength there, and that's right where it ties in to the end of the rocker panel.

Also worth noting, a unibody with significant floor pan damage is not structurally safe either, because the floor pan is a significant structural component. That section of floor pan is GONE, so, just on that the car isn't what I would consider structurally sound. The combination of the floor damage and the frame rail damage makes it a no-brainer, that's not a car you should be driving regularly, if at all.
Click to expand...

Thank you for the information! This is my first foray into working with a classic car, so I'm here to learn as much as possible.

I guess if it has to sit over the winter until next summer, that gives me plenty of time to learn and gather replacement parts. Based on cursory searches, complete rails don't appear to be readily available. So I'm guessing it'll be a fabrication job.
 
Dr C GT said:
I've perused AMD, but they don't have any 65 Dart frame pieces. And I'm not knowledgeable enough yet to know what is compatible between and across the various mopar.
Click to expand...

The rail itself is pretty much the same as the 67-76 A Body. Grab a used one from a newer A Body to use for a section to weld in (or trim/shorten the entire rail to match the ‘65 and weld the whole thing in from core support to Torsion bar crossmember.)

That’s what I did to my ‘65 Barracuda. At some point in her life a previous owner damaged the LF Rail and Torsion Bar crossmember (looks like it bottomed out at high speeds) and they boogered a patch plate on with an arc welder. I had a ‘68 Frame chunk (both rails, with fenderwells, complete back to the Torsion bar crossmember) given to me. I shortened the Torsion bar crossmember to match the ‘65 and replaced it, same with the LF Rail.
 
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