FYI on K-frames

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Rick@Laysons

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Folks, if you're working on your front ends, doing a re-build of your front suspension, or a general inspection, please give your K-frame a very good looking over. Pay special attention to the motor mount perches and the steering box mount.....and the tubes for the lower control arm bushings.

This one was TERRIBLE!!!!!

I ground out what welds I could get to with my angle grinder, fired up the welder, and while not museum quality....it's a helluva lot better than what it was.

View attachment 69 Cuda K-frame 001.jpg

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View attachment 69 Cuda K-frame 004.jpg

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View attachment 69 Cuda K-frame 006.jpg

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I hear ya Rick. I just dropped the one on my 68 Cuda vert. and it looks like someone tacked it together then went on break.
 
Monday at the plant I guess before coffee and aspirins. Mine was bad but that one......
 
Had a good friend spend four hours going over every seam and weld on mine before powdercoating.

The factory welds were pretty bad, he was kinda shocked how bad they were. I think he might've added a gusset or two, not sure, it was years ago.







 
Build quality was to cry about most of the time, but if factory welds really were that bad these cars would've all fallen apart at 5 years old.
Plenty of improvements can always be made on factory parts, mainly because parts weren't supposed to last 40 years and the fabrication process is always a compromise between costs, materials and intended use.
 
Mine k-Frame looked exactly same as first post. 1972 duster w/318.

Cleaned and rewelded mine, I also reinforced couple spot like steering box mount, lca mount etc.

Factory welds looked like my first MIG welds.


BUT if you think about it, mine car k member worked fine over 40 years with those crappy welds, not a single crack.

I have seen plenty machinery were factory welds failed after 10 years or less...
 
Before I started re-welding this K-frame, you could gently tap on it with a hammer and hear just how tinny and fragile it was. It had the sound of many pieces loosely held together. After re-welding it, you could tap on it and it sounded "solid" like it should.

If a person had installed it the way it was before re-welding, it would have been a disaster waiting to happen....and probably at the most inopportune time.
 
Yep, love that 1960s 1970s build quality. My 74 spool mount K was pretty bad too. After giving it a good douching with oven cleaner and a scrub brush to remove 20 lbs of crust, and caked on oil, I ended up cutting out the center splice on the underside, and welding in a piece of 1/8" steel plate to stiffen it up. I ground mine down at all the crappy welds, then bolted it into the car as a jig and thrn seam welded it, and added needed gussets around the steering box area. Lots of weld dressing and prep for paint is still needed, but Rome wasnt built in a day, and neither is this cuda.

You must also remember that assembly line jobs back then probably sucked, the japanese had not started to kick our asses in the auto industry yet, and the words "its good enough" were probably commonplace in detroit. Now its war and survival of the fittest between detroit, and japan. We are now used to todays high quality cars be it japanese or american made today simply because as a consumer we know it can be made better, and we refuse to buy the substandard **** we used to buy from detroit because they used to be the only game in town.
 
My 65 looked OK, maybe they had better QC back then, BUT my steering mount was cracked and had to be rewelded. I didnt even try as I got a clean used one for $50. I should have saved it to repair it but that was 20 years ago. Lots of tack and spot welds, but it did have a decent bead where there was a butt joint and around the LCA sockets.
 
I found a lower control arm tube broke free once.
To look at the welds on them I am surprised that is all I have ever found wrong.
I always give the welds a go over after that.
Seems they take a good beating from the looks of the dents in the bottom plate most have
accumulated from RR tracks or floor jacks.
Good advise to look at them close.
 
I am a armature welder, meaning I dont do it for a living. I have a good friend that welds for the military on Camp Pendelton and he laughs at my welds. I tell him to screw off, I NEVER had a weld fail, And I have laid down miles of bead. Welding is not about looks, it is about how strong it is. And as we see on our K frames, those shitty welds were strong enough, they made it this far! But my friend is all about "Art".
 
A couple of my steering box welds werent even stuck to both pieces and literally fell off when i ground on them. I guess it was ok for grandmas granny green 74 dart 4 door which is where i got the K frame from, but not good enough for autocrossing.
 
Stuff did fall apart back then. In the mid 70s Dodge had a problem with steering box mounts failing on the full size vans because of poor welds.

I bought a 74 B300 new and the build quality was terrible, it was a major piece of ****.
After driving it a week I took it back to the dealer with a list of about a dozen major and minor problems. One of the major problems was that the steering developed a half turn of play in it.
 
One of the major problems was that the steering developed a half turn of play in it.
Click to expand...

Sounds about right for a mopar gear box! LOL.
 
The steering box mount on the '74 Dart V8 K frame I swapped into my Duster (after fully seam welding and reinforcing it) was severely cracked. The welds along the K frame at the base of the mount had cracked completely, and when you turned the wheel the steering box would move back and forth too by a good 1/2" or so, closing and opening the cracked welds. There was so much flex that the mounting plate itself had cracked in the middle.

Crack at the steering box/engine mount weld

IMG_3520_zps8lqi5ekc.jpg


Crack at the steering box to K mount. I had already tack welded this one before I took the picture, but the entire "box" was broken free from the weld at the edge, the entire section between the arrows would peel open away from the K frame a good 1/4" when the steering wheel was turned.

IMG_3518_zps4fsxv0pr.jpg


Steering box mounting plate broken in half from all the flexing

IMG_3524_zps2ln78ues.jpg


The factory welds were hit and miss. There are numerous threads on here about the LCA pivot mounts breaking free of the K frame, and a handful of threads about torsion bar sockets ripping out of the crossmember. The factory never intended these cars to last past 100,000 miles. And they were designed for tiny torsion bars and bias ply tires that offered very little traction to transmit force to the frame/suspension. Even the hockey puck hard BFG T/A radials offer significantly more grip than the original bias ply's (and therefore transmit more force to the suspension and frame).

I seam weld and reinforce the K-frames on all of my cars if/when they come out. Even an amateur welder can significantly improve the stiffness and strength of a factory K member. Some factory welds are better than others, but some of them are downright scary. Not all of them absolutely need to be fully seam welded and reinforced, but if you intend to run better tires, brakes, or do anything other than cruise down the street to Dairy Queen it's not a bad idea. At the very least the K's should be cleaned and inspected on removal, to make sure you don't see things like the pictures above.
 
That crack looked just like my 65's. Would develop a shimmy at ~15mph that would blur your vision. Limped it home and replaced the entire K. It was like speed wobbles on a skateboard.
 
Thank you Rick for starting this post and including photos. My K frame while solid was a bit dented in on the bottom so I picked up another k frame and when I started to clean it up and inspect it more closely I was shocked at the weld quality. Good to know that this was common and not the result of some previous owners poor repair. That said, I will likely do some grinding and welding to finish what the assembly line started :).
 
Nice thing about it is its far easier to stick weld a K member than a header tube! Thick enough to take a stick no problem. And once you start, you dont want to stop as they lay down pretty good once you get going.
 
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