Lca pivot welded to k frame

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pinball

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Any idea as to why someone would weld the lca pivot shaft to the k-frame? Other than the lca bushing being shot I’m not sure if it indicates something else needs to be checked. The pivot shaft nut was pretty loose and I’m thinking that’s why the bolt hole on the front of the k frame is oblonged a bit. Disassembling for repairs and ran into this.
Thanks

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Yes. The holes were a oblonged from worn out bushings and rather than properly rebuild them l they quickly welded them in so they would not move.
 
Syleng1 said:
Yes. The holes were a oblonged from worn out bushings and rather than properly rebuild them l they quickly welded them in so they would not move.
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I agree.

And the inside k-member to LCA pivot bolt tube weld might have cracked.

OP: did it have Poly bushings on the LCA? It would be tricky to weld that stud on while everything was installed with rubber pressed on bushing.
 
Bushings are rubber autoxcuda. Was worried it could be indicative of something else being tweaked, but glad to hear it’s likely just laziness. Ideas on removing the pivot shaft without tearing into the k member too badly? Carbide bit on a die grinder?
 
dang that’s a different takeaway than I originally had. Why is it that my k-frame can’t be fixed? Just trying to understand I appreciate the information I’m getting.
 
Oh good grief. The LCA was welded to the pivot shaft? Or the pivot shaft was welded to the K member?

The brain trust that did that clearly has no clue how the suspension functions. The pivot shafts don’t turn. They’re held fixed in the K member while the LCA pivots about the shaft. If the LCA was welded to the pivot shaft, the pivot shaft then has to turn for the suspension to move, which isn’t how it’s supposed to work at all.

And if the holes in the K member are oblong, you’ll have to open up thr K frame and fix that. And likely replace the pivot tube that’s supposed to be welded solidly into the K frame.
 
pinball said:
Pivot shaft is welded to the k-frame.
I’m in North Dakota.
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That's what it looked like in the pictures, but you said the pivot shaft was welded to the LCA in your post. More than likely the pivot shaft tube broke loose inside the K frame, and the "fix" was to just weld the shaft into the K.

The pivot tubes can be replaced, you'll have to open up the K frame to do it though. Member @Jim Lusk has performed repairs like that, now that he's tagged maybe he'll share some pointers. The pivot tubes were just spot welded in from the factory, and some were not done particularly well. I wouldn't say it's a common problem for them to break loose but it definitely happens.

If you can weld, you can open up the K frame and replace the pivot tube. Given the holes in the K are messed up too I'd replace a section of K on the front and the back so I could drill a nice round hole in the patch metal. So you'd have a new pivot tube and nice round holes on both sides. It would require some patience, as you'll need to have the pivot tube located properly and level so you don't accidentally move the location of the LCA and totally bugger your chances of getting a decent alignment later. If only one side is messed up you can use the other side of the K as your guide.
 
You should be able to get in there easily with an angle grinder and fiber wheel and cut that weld, but I lean toward what @Oldmanmopar said about replacing the k frame. I'd be thinking about all the other stress cracks that I couldn't or didn't see.
 
You may be able to gain some knowledge by searching member Jim Lusk, he has a ton of info on k-frames and repair .
He shows up this link, understand he has some vids, not sure if pertinant.
Good Luck
www.forabodiesonly.com

Pivot shaft to K-frame bushing fit

When you put the pivot shaft into the K-frame hole by itself loosely, how tight is the fit suppose to be? Is it zero play or tiny amount of play? I assume once you tighten the nut to 145lbs, you would think it would not matter. When I took my lower control arms outs, the pivot oval...
www.forabodiesonly.com www.forabodiesonly.com
 
It’s a 1969 340 car. Thanks for all the advice it’s really appreciated.
 
Someone went to the dealership and purchased a replacement control arm shaft. Notice the ball shaped part of the shaft where it enters the k member. That design was not available in 1969, even though both shafts are interchangeable. If a person has no experience repairing K members, it might be better to replace it.
 
RustyRatRod said:
I thought he was talkin about the K frame.
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He is. QA1 is the only place that makes a replacement K that works with torsion bars. There are plenty of others, but they’re coil over conversions.
 
72bluNblu said:
He is. QA1 is the only place that makes a replacement K that works with torsion bars. There are plenty of others, but they’re coil over conversions.
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Oh ok. Now I see said the blind man. My bad. Heck, I'd just look for a good used one.....
 
RustyRatRod said:
Oh ok. Now I see said the blind man. My bad. Heck, I'd just look for a good used one.....
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Yup, nothing wrong with looking for a used one. Especially if the OP isn’t up to repairing the one he has himself.

That said, almost all the used ones are like 50+ years old, and the factory welds were pretty sketchy on some of them. So any used replacement should be fully inspected for cracked welds, rust, damage, and being straight. Wouldn’t be too hard to unintentionally replace one bad K frame needing repair with another one that needs also repair if you’re not careful.
 
72bluNblu said:
Yup, nothing wrong with looking for a used one. Especially if the OP isn’t up to repairing the one he has himself.

That said, almost all the used ones are like 50+ years old, and the factory welds were pretty sketchy on some of them. So any used replacement should be fully inspected for cracked welds, rust, damage, and being straight. Wouldn’t be too hard to unintentionally replace one bad K frame needing repair with another one that needs also repair if you’re not careful.
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I agree. They were sketchy when they were new. Just good enough to get out of the assembly plant.
 
The tube is not a straight tube. It has a taper at one end for an interference fit with the pin (see pics). I could fix it, but it wouldn't be cheap. Even the shipping wouldn't be cheap. Figure a couple hundred or more in shipping and a couple hundred to fix it. You can replace it with another K-member (any '68-72 V8 K-member would work, but at some point 340 K-members got a washer welded to them), BUT you may also run into problems with the pin tubes or straightness. The pin was likely welded because they couldn't get the nut tight. When I work on a K-member they get bolted into a jig that tells me how straight and square the K-member is. Minor repairs are easy, but big tweaks are not.

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