fixing dents in botton of frame rails?

daveL82

daveL82

Well-known member
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Apr 10, 2008
Messages
231
OK the problem sounds worse than it is but it's something I want to address while the car is on jack stands.

I've owned the car for 25+ years and after many years of using the jack on the frame rails the lower portion has a number of dents and in some areas the metal is pushed up 1/4" maybe a bit more. keep in mind the car has been inside most of it's life when not being driven so the frame isn't rusty it's just too damn thin. I don't see an easy way to do this without cutting the bottoms own with a saw and then either straighten the old metal or weld new stuff in. Maybe an opportunity to go to 3/16"?

Anyone else done this?
 
Are you talking specifically about the engine crossmember? Someone made a tool for it, you will have to google it but it's out there
 
These are the side frame rails from the end of door to the frame kick up near the front fender vents. Doesn't look too bad from the side but when I look at it from underneath it does. These frames are not very strong for sure.
 
I jacked mine up there all the time and don't have a single dent, are you sure your chassis is not rusty on the inside?
 
Believe me no rust. I've had the car since 83 when I bought in Georgia with 29K miles on it. I've looked in side and no rust. This started not long after I bought it and of course it just gets a bit worse over time.

I recently had to notch out the diff cross member for exhaust to clear my new lower a-arms in the rear. Looked in there while it was open and no rust there either.
 
daveL82 said:
These are the side frame rails from the end of door to the frame kick up near the front fender vents. Doesn't look too bad from the side but when I look at it from underneath it does. These frames are not very strong for sure.
Click to expand...

I've got the exact same thing, and would like to learn a fix for it as well. I"ve thought of welding plates in that area, and that would strengthen it, but I'd like to fix it first. My car's from Colorado and there's no rust in it either.
 
It sounds like your dents are cosmetic and not structural. My solution may be worth just what I am charging for it, but here goes. If the dent is 1/4 inch deep or more, it will need to be pulled. This will leave smaller dents that can be cosmetically removed by layers of JB Weld. I have successfully repaired dented oil pans this way with good results. A guy I knew years ago, who professionally restored vehicles, shared this solution with me.
 
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*start rant*
In my opinion the frames are stitchwelded junk and if I wasn't lazy and if I didn't have so much other stuff to do I'd pull the body of my '79 and fix it once and for all.... I am sure one day I am going to pull the body and weld the frame as it should have been done 30 years ago... :mad:
*end rant*

you could try to drill holes and pull the dents with a slide hammer, then weld the holes shut, grind wleds flush and apply some epoxy primer on the clean steel.... don't forget to protect the inside after the repair....

I like the JB weld "putty" idea for cosmetic repairs - apply etching primer or epoxy primer first, I wouldn't trust JB weld on bare metal.
 
MYBAD79 said:
*start rant*
In my opinion the frames are stitchwelded junk and if I wasn't lazy and if I didn't have so much other stuff to do I'd pull the body of my '79 and fix it once and for all.... I am sure one day I am going to pull the body and weld the frame as it should have been done 30 years ago... :mad:
*end rant*QUOTE]

Yeah, I've been thinking of doing just that. Plus, there's so much else that could be done.....don't tempt me!!

The dents are cosmetic only (I'm assuming), when I had the car aligned, there weren't any issues so it hasn't effected that, and none of the panels appear to have shifted. This is right where I put jack stands if I want the front suspension off the ground, so a JB weld fix would look good until the next time a jack stand was there. My jack stands are pretty big, but the pad doesn't span the frame rail width and I'm sure that's what's caused this. I think the best solution at this point is to fit and weld plates in this area on both sides. That way, I can still use this area for support with the stands.
Click to expand...
 
MYBAD79 said:
*start rant*
you could try to drill holes and pull the dents with a slide hammer, then weld the holes shut, grind wleds flush and apply some epoxy primer on the clean steel.... don't forget to protect the inside after the repair....

I like the JB weld "putty" idea for cosmetic repairs - apply etching primer or epoxy primer first, I wouldn't trust JB weld on bare metal.
Click to expand...

I was thinking of pulling frame dents with the body on and by just welding the head of a hex bolt to the center of the dent, drilling a hole in a piece of channel; with the bolt coming through the channel, simply tighten with a nut and washer. Heat from a torch, around the inside perimeter of the dent will help control the pull. Place flat stock under the channel edges to spread the load and avoid more dents.

JB Weld is made to go directly on the bare metal. The metal must be rust free and clean, scuffed with some 80 grit helps it bond. Wiping with wax/grease remover, or lacquer thinner is a good idea. I repaired an aluminum two stroke block, after a rod punched through, with JB Weld and the engine ran fine as long as I owned it. It dries hard, much harder than Bondo.

Raising a C-3 from the frame on one side is not a good idea because of the weak frame. If one must raise it that way, it is a good idea to spread the load over a larger area by using a large flat jack cup with a rubber protector. The Harbor Freight aluminum racing jack has the perfect contact surface IMO. If your jack has a castellated type cup, place a rubber puck in it, or rubber boat trailer accessory for example. Jack stands usually have two high spots that are sure to leave dents. I always use a piece of wood between jack stands and frame. My front end is always raised from the front and under both control arms, not the center, or frame rails. My frame has no dents made by me.
 
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MYBAD79 said:
*start rant*
In my opinion the frames are stitchwelded junk and if I wasn't lazy and if I didn't have so much other stuff to do I'd pull the body of my '79 and fix it once and for all.... I am sure one day I am going to pull the body and weld the frame as it should have been done 30 years ago... :mad:
*end rant*
Click to expand...

While you have the body off, slide one of these underneath. Problem solved! :smash:

534a468ea33f0e9.jpg
 
I think I'll cut the flat sections out each side then weld in 3/16 plate all along with full welds. Should be stronger than original.
 
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