What broke in my suspension?

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McGurik

McGurik

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Hey FABO, I was pulling my dart out of the driveway yesterday and heard "POP" right before the driver's side took a nosedive into the pavement. I got out and saw that it was resting on the lower bump stop; nothing actually hit the ground. Jacking the car on the pavement, I noticed the perch, that the adjustment bolt touches, was turned nearly vertical! So I removed the torsion bar, to release the tension, and moved the perch back down to the adjustment bolt with the bolt nearly threaded out. I lowered the car and it promptly rested on the lower bump stop again. I got it back into my driveway but it's raining today so I will not get to really assess what broke.

My rudimentary assessment is that there is no resistance for the torsion to prop up the weight of the car. So I am thinking that either the hex socket in the transmission cross member broke free and is spinning; unlikely as this is a CA with little rust. Or something broke in the LCA that does not resist the perch from rotating. I have yet to tear apart a LCA so I am unfamiliar with their construction; FSM isn't much help either. These are PST 1.03" bars and the "L" is on the driver side.

Does any of this sound familiar or can someone recommend what to look for first?
 
Most likely what Roy ^^^^^^^ said, then. It's possible it broke loose either from rust or bad spot welds. They are kinda notorious for bein a weak spot.
 
Either the rear hex seperated from the crossmember or the front adjuster did the same from its self

OR

the hex on the torsion bars is way too small and spun
 
Dana67Dart said:
Either the rear hex seperated from the crossmember or the front adjuster did the same from its self

OR

the hex on the torsion bars is way too small and spun
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Your lower control arm bushings is shot. They're not the easiest thing to replace but that rubber doesn't last forever.
 
The rear torsion bar anchor is the most likely culprit. It doesn’t even have to be rust related, some of the factory welds there were pretty bad to start off with. Although just being a California car doesn’t mean it’s rust free there either, portions of the crossmember have access holes so dirt and animals can get in there. A nest made out of upholstery holds water and can cause very localized rust through.

It’s also possible that the lower control arm pivot tube broke loose in the K frame, but that would have to be a pretty extreme case to completely unload the torsion bar like that. Maybe coupled with a blown out bushing.

My bet for a loud catastrophic failure that wasn’t the torsion bar itself would be the rear anchor though.
 
Thank you all for the responses. Ill do some digging, weather permitting, and let you all know what I find.
 
Another vote for the rear anchor. I have never seen or heard of the arm in the LCA breaking loose from that anchor. Also, with larger bars there is more stress on the rear anchor. Breaking the pivot pin tube loose is also an unlikely cause.
 
One other suggestion too. I've seen the adjuster bolt on control arm fail on someone once. It was agreed that someone tried to adjust ride height with the weight on suspension causing the threads to strip and bolt to pop back off adjustment.
 
Don't weld the socket back in have the cross member replaced. If one side broke out the other is probably weak. Clocking them and getting them at the correct angle is tough. What year Dart I may have one. Steve 67-69 are the same 70-76 are the same. The difference is the size of the cross member bolts.

DSCN2867 (2).JPG
 
Oldmanmopar said:
Don't weld the socket back in have the cross member replaced. If one side broke out the other is probably weak. Clocking them and getting them at the correct angle is tough. What year Dart I may have one. Steve 67-69 are the same 70-76 are the same. The difference is the size of the cross member bolts.

View attachment 1715488503
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A ton of work that may be totally unnecessary.

If rust is the reason it broke then replacing the whole crossmember may be the best option. But if it just broke because of a poor weld, which is very possible, then there’s absolutely no reason to replace the whole crossmember.

If it was a poor factory weld you should have no problem welding the anchor back into place and gusseting it. And then you can gusset the other side to match and be on your way. I gusset the torsion bar anchors on all of my cars regardless, it goes right along with seam welding and gusseting the K frame. Some of the factory welds on these cars are terrible.
 
72bluNblu said:
A ton of work that may be totally unnecessary.

If rust is the reason it broke then replacing the whole crossmember may be the best option. But if it just broke because of a poor weld, which is very possible, then there’s absolutely no reason to replace the whole crossmember.

If it was a poor factory weld you should have no problem welding the anchor back into place and gusseting it. And then you can gusset the other side to match and be on your way. I gusset the torsion bar anchors on all of my cars regardless, it goes right along with seam welding and gusseting the K frame. Some of the factory welds on these cars are terrible.
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And you had to quote me to give your opinion?

I was going to blame it on the poly LCA bushings to get you to chime in. It doesn't even take that anymore.

Just took another set of those powdered up poly bushings out of another car that came here. The guy said he put them in 3 years ago. I told him he didn't install them properly like you said. Yours lasted over 20 yrs. Putting the lube on takes experience. You know whacks on Whacks off. I warned him. You gotta have the correct amount of lube .
 
Oldmanmopar said:
And you had to quote me to give your opinion?
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Yes. You're suggesting he buys an entire crossmember from you without having seen a single thing, which is completely overkill and I'm sure has a lot to do with the fact that you're trying to sell the him the part.

He's in Southern California. While it's not impossible for the rear anchor failure (if that's even what he has) to be from rust in the crossmember, it's more likely that it's just from a lousy factory weld. Either way, no one has seen pictures yet so suggesting he buys an entire crossmember from you is more greed than help.

Oldmanmopar said:
I was going to blame it on the poly LCA bushings to get you to chime in. It doesn't even take that anymore.

Just took another set of those powdered up poly bushings out of another car that came here. The guy said he put them in 3 years ago. I told him he didn't install them properly like you said. Yours lasted over 20 yrs. Putting the lube on takes experience. You know whacks on Whacks off. I warned him. You gotta have the correct amount of lube .
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And what does this have to do with helping the OP figure out his car?

Just more grandstanding. No need to derail this thread too just because you still don't understand the basics of why installing poly bushings is different from rubber.
 
How about some pic's, any, to relieve the conjecture! No need in members using good intuition guessing and getting testy with each other!
 
1969383S said:
How about some pic's, any, to relieve the conjecture! No need in members using good intuition guessing and getting testy with each other!
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Sorry been busy working in the Emergency Department all week. Just got a look today.

Looked like a bad weld at the trans cross member.

308DE6CC-438E-4A61-836F-8375960E3378.jpeg


8A05EAD0-EB42-497E-8C2A-7AE8F65FD734.jpeg
 
Jim Lusk said:
Yup. Should be able to get it back to the correct spot.
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Which leads to my next question, what is the proper alignment? I saw a thread with pics that @72bluNblu posted and looked like two points were at 12 & 6. Is that standard? Is each car a little different?
 
Dfr360cuda said:
Torsion Bar Crossmember Reinforcing Plates Now Available! $25/Pair

Here's an option
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As far as I know he’s no longer making any of that stuff.

The plates are pretty easy to make though, even with just pretty basic tools.

McGurik said:
Sorry been busy working in the Emergency Department all week. Just got a look today.

Looked like a bad weld at the trans cross member.

View attachment 1715490694

View attachment 1715490695
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Yessir, that’s just a cold weld. No need to replace anything. Pull the torsion bar, line up the anchor and weld it back in. Some kind of gusset plate added into the mix would be ideal.

Also, you should re-weld the other side too. Since the weld on one side failed there’s a good bet the other side will too if not addressed now.


McGurik said:
Which leads to my next question, what is the proper alignment? I saw a thread with pics that @72bluNblu posted and looked like two points were at 12 & 6. Is that standard? Is each car a little different?
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All of my cars, my Duster, ‘71 GT, and ‘72 challenger all have the torsion bar anchors oriented the same way, with a point at 12 & 6.

It should go without saying that all of these cars are a little different as factory tolerances were kinda loose especially by today’s standard. But they should all be about the same in that respect. The other thing is that the torsion bars are clocked, not the anchors, so realistically you should just be able to look at the passenger side and copy that. The anchors aren’t offset one side to the other. You want it close, but if it’s not dead on any difference will be taken up at the adjuster when you set the ride height. Rarely are the adjusters set identically on both sides. They should be pretty close, but none of them are perfect.
 
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