Author Topic: 70 Cuda front suspension question  (Read 2706 times)

Offline Simple

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70 Cuda front suspension question
« on: September 04, 2017 - 09:45:17 AM »
I just replaced the torsion bars along with all new upper and lower bushings and ball joints. I took car in for a alignment and they can't get it to align properly because when they set the height by adjusting the torsion bars and drive it around the parking lot the front end drops back down to top of the tires.  They aligned it three times and sent it back. The front tires lay in at the top after it drops. The car is lowered a bit from stock but that shouldn't matter. Any suggestions or has anyone ever had this problem ?? I'm baffled.




Offline HP2

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Re: 70 Cuda front suspension question
« Reply #1 on: September 04, 2017 - 09:56:57 AM »
Torsion bar rear anchors may be cracked and twisting in the frame or lower control arm anchors are cracked and twisting in the sub-frame.

Offline GoodysGotaCuda

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Re: 70 Cuda front suspension question
« Reply #2 on: September 04, 2017 - 10:44:26 AM »
Torsion bar rear anchors may be cracked and twisting in the frame or lower control arm anchors are cracked and twisting in the sub-frame.

That's about the only explanation I can com up with, unless the threads in the adjusters are just stripped enough to hold statically, but as soon as it hits a bump it falls on threads.
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1976 Dodge Warlock
1972 Barracuda - 5.7 Hemi + T56 Magnum

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Offline HP2

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Re: 70 Cuda front suspension question
« Reply #3 on: September 05, 2017 - 10:13:02 AM »
If it is getting a lot of negative camber when this happens, I'd suspect something in the lower control arm mount area has broken and is allowing several degrees of movement. Upper arm mounting bolts could also be loose.

Offline 70chall440

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Re: 70 Cuda front suspension question
« Reply #4 on: September 05, 2017 - 05:03:12 PM »
You would think that the shop that did the work would have figured it out, if they adjusted it and took it out and the front end dropped; they surely would have seen that the screws they had just adjusted were either in the same place (adjustors broken) or back out (threads stripped)... This is pretty simple as it can only be a couple of things.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline Beekeeper

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Re: 70 Cuda front suspension question
« Reply #5 on: September 05, 2017 - 10:04:44 PM »
You would think that the shop that did the work would have figured it out, if they adjusted it and took it out and the front end dropped; they surely would have seen that the screws they had just adjusted were either in the same place (adjustors broken) or back out (threads stripped)... This is pretty simple as it can only be a couple of things.

I was thinking the same thing...this suspension design isn't all that complicated. If a component is failing, it should be fairly obvious to them. The fact that they don't know kinda makes me think they don't know Mopar suspensions very well.

You mentioned that the front tires lay in a bit and also that the car has been lowered from stock. How was it lowered? Are the front spindles originals?

Offline HP2

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Re: 70 Cuda front suspension question
« Reply #6 on: September 06, 2017 - 09:23:51 AM »
With most shops toe and go mentality, I wouldn't place a bet a  how knowledgeable anyone is until they demonstrate otherwise, even if they drive classic camaros or not.

Offline 70chall440

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Re: 70 Cuda front suspension question
« Reply #7 on: September 06, 2017 - 12:22:45 PM »
With most shops toe and go mentality, I wouldn't place a bet a  how knowledgeable anyone is until they demonstrate otherwise, even if they drive classic camaros or not.

I would agree that most shops are not overly "investigative" but since they supposedly did the adjustment multiple times, even the most disinterested mechanic would wonder what was going on; if you adjusted ride height in the shop, then backed out and the fenders were on the tires... surely was a "WTF" moment/s.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline burdar

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Re: 70 Cuda front suspension question
« Reply #8 on: September 06, 2017 - 01:42:49 PM »
I read about this issue once...many years ago on Moparts.  It was happening on a Demon.  As was suggested here, most people said it had to be the torsion bar sockets in the x-member causing the issue.  That wasn't the problem.  If I remember correctly, it had to do with the alignment itself.  It didn't make sense to me but I remember the proper alignment fixed it.

You can put a grease pencil mark on the x-member and torsion bar to eliminate that as a possibility.

Offline 70chall440

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Re: 70 Cuda front suspension question
« Reply #9 on: September 06, 2017 - 02:31:37 PM »
I think everyone who has responded is reacting to the information itself which might not be accurate, what I mean is that when I was doing the alignment on my Challenger, I had several instances of setting the alignment then pulling out only to have the passenger tire "collapse" the camber meaning that the top of the tire was leaning dramatically inwards toward the center of the car. This looks like the tire is now "up and inside" the fender; if this happens on both sides, it would look somewhat like the ride height is being altered or failing (kind of is, but has nothing to do with the torsion bars).

What causes this is the upper control arms moving in their adjustment slots (usually the front, but could be both). This is a result of 1 of 2 things, first is an improper alignment which is placing significant stress on the UCA's and pulling them, and/or the adjustment bolts not tightened correctly or sufficiently. In my case it was a combination of things but everything stemmed from the toe adjustment being way too far out putting a significant amount of force onto the UCAs.

Normally someone doing alignment would set caster, then camber then toe last. What I found is that with these cars (vintage Mopars) is that if using stock or factory parts the following,

Caster isn't really adjustable to a large degree, rotate the rear UCA adjustment all the way out and that's as good as it gets.
Camber can be adjusted slightly. most say turn the adjustments all the way in and you are close
Toe can be set to 1/16" in

Well, I can say for sure that in my case, I needed to set the Toe very close, then go back and check the Camber leaving the Castor (rear UCA bolts alone) before attempting to move the vehicle. I had to learn this the hard way and had to mess with it many times before I figured out that while the Toe was relatively close (or so I thought), in realty the passenger side was pointing out and trying to go a different direction than the drivers side. I ended up spending some quality time ensuring that both wheels were pointed in the same direction, then sent the actual Toe, then went back and checked the camber, then locked EVERYTHING down.

One last part and I will get off the box... if you rebuilt the front end using a "kit" from someone like PST (nothing really against them) you might be using poor quality UCA adjustment bolts. The ones you get in many kits have the flat for the eccentric washer machined all the way to the bolt head (effectively removing 1/3rd or so off the bolt) whereas the originals were only machined on the threaded end leaving the body of the bolt round and intact. I mention this because the aftermarket bolts tend to "lose grip" and can allow the UCA to move. I ended up sourcing some high quality Dorman UCA bolts to combat this; this is absolutely and issue if the Toe is off when the shop/technicians attempts to test drive; it will cause the UCAs to move and the Camber to move dramatically resulting in the tires leaning in (or maybe out, but in would seem like a ride height issue).

In short, it might not be a ride height issue at all but something else. Bottom line is that the shop you are using may not be experienced or understand old Mopar suspensions... 

Sorry for the rant, hope something here is helpful to someone.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline Aracer

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Re: 70 Cuda front suspension question
« Reply #10 on: September 21, 2017 - 07:07:50 PM »
I thought the rear castor setting, bushing, is all the way inside, to start the set up? Then you need to move out, the side that is more positive, next adding to the neg. camber to compensate, for the camber that gets reduced simultaneously.
When you move the back ones out the fronts have to go in to equalize. PITA to repeat until it's correct.