Bent and cracked LCAs, and broken LCA to K-frame attach point pics

[375instroke]

Bad potholes?  Dukes of Hazard wannabees?  What happened to my car?  The frame isn't bent.  There's no sign of damage or repair.  When I got the car, the steering column was installed 180° out, and the tie rods were maxed.  One all the way in, and the other side all the way out, to get the steering wheel straight.  The car turned like a battleship left, and on right turns, the right tire hit the frame.  Don't know if that's related at all. 

Here's the right side.



You can see two tears above the weld.



Right control arm bent back.  Shock mount is twisted, too.



Crack.


Blown up?



Left side.



Crack.



Blown up.

[JB400]

I'm going to have to agree with the DoH theory.  I think someone wasn't paying attention and hit a few curbs or something at an excessive speed.  I see a new k member in your near future.  I think I'd check your upper control arms and spindles as well.

[myk]

Looks like my control arms after I jumped my car off of a freeway on-ramp onto the freeway below back-in-the-day.  Fixing that damage cost about $6K and that was back in '96.  Took months to find the parts too, because Al Gore hadn't invented the internet yet; we had to call junkyards all over the country because even Stephen's Performance didn't have anything for me.  It took years to get the car back to where it needed to be.  Good luck 'OP, it can be fixed...

[Budnicks]

Damn that looks pretty nasty, good luck with your suspension repairs, I would say to rebuild the whole front end, if you found that on one side...

[tan top]

Damn that looks pretty nasty, good luck with your suspension repairs, I would say to rebuild the whole front end, if you found that on one side...

 would rebuild the whole front end !!   be intresting to see if the K frame is  under tension &   alignes ok again  if  the bolts are removed    would be   giving  every thing under there a good inspection     same deal with torsion bars  , & strut rods , have a look  they might be bent  

[375instroke]

I was in the process of rebuilding.  The car drove straight and maintained alignment.  I just didn't expect much from it in the handling department.

[bull]

If you ever get down the freeway a ways to Vancouver bring the K-frame along and give it to the Firm Feel guys. Send them some pics of this stuff and they'll let you know if they can rebuild it and reinforce it, which I would recommend you do anyway. They could probably fix your LCAs too if you decide to reuse them.

http://www.firmfeel.com/reinfkfram_b.htm

[elacruze]

I didn't go all the way in for the reinforced K member, but I did buy the LCA reinforcement plates and weld them on.

[Mike DC]

 
I'm not convinced that it had to be any specific ugly abuse to do this.  

Usually a single impact hard enough to break the suspension parts like that, is also hard enough to bend the unibody.  Like, visibly bend it.      


The K-frame mounting tube tearing out . . . that can happen just from normal metal fatigue, given enough hard miles on the car.  It's a common weak spot which is being revealed more & more often as these cars age.  It's something that should be at least checked, if not reinforced, as part of a normal overhaul these days.



No way to know for sure on the LCAs.  But it wouldn't surprise me if the LCA damage on this car was just the chain of events following the K-frame mounting tubes giving out.  The LCAs bend pretty easily if something at either end of it gives out.  They are only designed to have a lot of strength in the vertical direction.  

I once had a LCA strut bolt break off.  The LCA itself bent way backward before I could limp the car home a mile or two.  

[myk]

I'm not convinced that it had to be any specific ugly abuse to do this.  

Usually a single impact hard enough to break the suspension parts like that, is also hard enough to bend the unibody.  Like, visibly bend it.      


The K-frame mounting tube tearing out . . . that can happen just from normal metal fatigue, given enough hard miles on the car.  It's a common weak spot which is being revealed more & more often as these cars age.  It's something that should be at least checked, if not reinforced, as part of a normal overhaul these days.



No way to know for sure on the LCAs.  But it wouldn't surprise me if the LCA damage on this car was just the chain of events following the K-frame mounting tubes giving out.  The LCAs bend pretty easily if something at either end of it gives out.  They are only designed to have a lot of strength in the vertical direction.  

I once had a LCA strut bolt break off.  The LCA itself bent way backward before I could limp the car home a mile or two.  

So if this is a potentially common failure point, would you recommend the Firm Feel reinforcement (K member and LCA reinforcement) that was mentioned above?  What other recommendations would you have?  Would it be better to buy aftermarket LCA's?

[bill440rt]

Metal fatigue.      Years of use. That is not from a single impact.
Control arms are junk, discard them. If you can find a replacement k-frame, IMHO that would be a better way to go than repairing that one. You might have more in it repairing it than finding a clean replacement.
Good to hear no one was hurt.

[375instroke]

The tube still fits nicely in the lower part of the K-frame, so locating it in the proper place when I weld it isn't a problem.  I'd rather change to a '70 K-frame, though, since I need new control arms, too.

I wonder what the stiffening plates do.  The control arm bent outboard of where the strut rod connects.  That's where the stiffening plate ends, so what good would it do?

[myk]

What's the difference between the '70 K member and the other ones?

[Mike DC]

In 1970 the swaybar was relocated inside the middle of the K-frame, like on the E-bodies.  (Although the E-body K won't interchange because of the steering box angle.)  The 1970 K-frame must also use 1970 LCAs because of the swaybar mounts on the LCAs being in a different place.

1969 front suspension parts, or 1970 . . . either way I agree to buy some better-condition used parts and don't try to fix those.  K-frames and LCAs apply to the entire B-body platform so they aren't very expensive.  The alignment of the important stuff on them cannot be very far off before it starts causing trouble.  The parts on this car obviously fatigued enough to break and there are plenty of other parts out there which are not close to being so bad.  Replace them, it's cheap insurance.   



The main thing needed to avoid this failure is to beef up (weld extra plating on) the mounting points of the LCA in the K-frame walls.  You can put some heavy washers/etc around the tube ends, weld them to the tube ends, and weld the outer edges of the washers to the walls of the K-frame.

[375instroke]

I wonder why only the back of the tube is welded.