How 'bout them frames?

Author Topic: How 'bout them frames?  (Read 1703 times)

Offline ViperMan

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How 'bout them frames?
« on: April 18, 2007 - 04:09:20 PM »
Well again I didn't see anything readily available to answer this, so here goes:

I've got a '73 Barracuda.  I believe it suffers from the sagging frame syndrome.  Now, I only know about it because I read about it on Year One - they have an eccentric kit for aligning cars with sagging frames.  My caster is severely out of whack at both front corners.

My question is where exactly does this sag happen?  I mean these are partial unibodies, so where does this sag occur?  Has anyone experienced fixing this issue?  Obviously it requires a full tear-down, but how far down?  Fenders off, bumper off, engine out?  Or worse than that?

And as far as these eccentric adjustment kits - anyone have experience with them?  I know how eccentrics work, so how does a kit exist that allows adjustment beyond the factory range?

Jeff
2000 Dodge Viper GTS Coupe - 8.0L V10, 6-Speed Tremec
2005 Jeep Grand Cherokee Limited - Trail Rated - 4.7L V8, Auto
2010 Dodge Challenger SE Rallye - 3.5L V6, Auto (Wife's!)




Offline purple1

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Re: How 'bout them frames?
« Reply #1 on: April 18, 2007 - 04:27:33 PM »
Unless your car has been crashed and fixed. Or driven hard, I mean racing it or jumping over hills or something. You just need to rebuild your front end. The sag is from worn out parts. I am going to do a rebuild of mine soon using a kit form www.p-s-t.com. I got the Super front end kit plus the pitman arm.

Dave  :wave:

Dave


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Offline ViperMan

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Re: How 'bout them frames?
« Reply #2 on: April 18, 2007 - 07:44:28 PM »
Hmmm, okay.  Well, I know I haven't jumped it, but who knows for those who owned it before me!  I'll check out that site.  Thanks.

Jeff
2000 Dodge Viper GTS Coupe - 8.0L V10, 6-Speed Tremec
2005 Jeep Grand Cherokee Limited - Trail Rated - 4.7L V8, Auto
2010 Dodge Challenger SE Rallye - 3.5L V6, Auto (Wife's!)

Offline 360 'CUDA

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Re: How 'bout them frames?
« Reply #3 on: April 18, 2007 - 08:26:35 PM »
That whole sagging deal is a Mustang thing.  It doesn't mean you don't have a tweak or two that needs attention but almost every unrestored sixties Mustang does that.

Probably needs a rebuild kit and maybe a MIG weld here or there but I wouldn't worry about it unless you find an obvious kink or bend on the longitudinals  :2thumbs:

Offline moper

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Re: How 'bout them frames?
« Reply #4 on: April 19, 2007 - 09:40:54 AM »
Unless it's VERY rusty, mopars dont sag due to bodies. If your alignment guy is good enough to know torsion bar suspensions (ride height is critical on the alignments) and he can't get it in, check for worn parts, bushings, and also the K frame where the lower control arms pass thru it. I have seen (and owned) several that the K frames failed in that area.

Offline ViperMan

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Re: How 'bout them frames?
« Reply #5 on: April 19, 2007 - 03:13:48 PM »
okay - that's a good place for me to start - any idea on what the ride height should be on these?  It wasn't level when we started (I myself am the alignment guy,) so we lowered the pass side to match.  I measured from rockers just behind the wheel wells.  I didn't have time to get detailed with is as I was leaving for my wedding in two days, so we got it level and I did the best I could with the eccentrics.  Right now she pulls to the left, but the caster is reading NEGATIVE on both front wheels.  There's no way that's accurate, but if the caster is bad enough, it'll throw the readings out pretty bad.

The frame/underside is almost rust-free.  In fact I was surprised at how clean it was.  Then again there is a hole in the driver's floorpan which was poorly repaired - that's on my list of things to deal with.

But from what I'm learning, I just need to invest in some new suspension parts - probably including torsion bars - A-arms, bushings, shocks and such - that should at least let things "reset" so I can start anew...

Jeff
2000 Dodge Viper GTS Coupe - 8.0L V10, 6-Speed Tremec
2005 Jeep Grand Cherokee Limited - Trail Rated - 4.7L V8, Auto
2010 Dodge Challenger SE Rallye - 3.5L V6, Auto (Wife's!)

Offline HP2

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Re: How 'bout them frames?
« Reply #6 on: April 19, 2007 - 03:38:48 PM »
It is entirely possible that you have negative caster, as that is what was typically put into these cars way back when and most shops won't know to do any differently.

Caster and camber is adjusted via the eccentric bolts on the upper control arm. As these are rotated they change the setting. The problem solver upper control arm bushing kit you speak of has the bushings offset in the housing, that then presses into the control arm.  By offsetting the bushing and offsetting the eccentric bolt, you can get a very large range of adjustment.

FYI, if your doing your own alignment, then shoot for these specs; as much POSITIVE caster as you can get. Camber -.5, toe 1/32 in to zero. Ride height I always set to where I like it with the tires I'm going to use. I never use the factory spec.

A rebuild is never a bad idea, unless it has been done within the last ten years, and it will gain you a lot of improvement over the worn out original stuff.

Offline ragtopdodge

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Re: How 'bout them frames?
« Reply #7 on: April 19, 2007 - 05:29:48 PM »
If you need a lot of caster, w/some more camber adjustment, go w/the tubular a-arms (adjustable) being offered by RMS, or MagnumForce, or XV, or ???.
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Offline moper

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Re: How 'bout them frames?
« Reply #8 on: April 20, 2007 - 09:55:13 AM »
The "official" ride height is published in the fasctory service manuals, as is the method of figuring it. What I find is even if the cars had front end work done, they are set too low in teh nose. The cars were almost level (except the AAR/T/As) when they were new. Dropping the nose is common, and most alignment shops take the height the car is set at when teh suspension is bolted back as the ride height. That's wrong. I know several cars that replaced the control arm bushings or used tubular A arms to get the right alignment specs, when all they really needed to do was lift the nose via T bars to get the "specs window" inside the adjustment range. You should be able to get 2° of positive caster out fo a properly set stock front end. Some cars will get more. But all should be able to get at least that. I do my own alignments too, so I can sympathize with you. If you cant get the caster past "0", the car's nose is too low or the rear is too high. It is also common for the reproduction springs to sag very quickly, or not be anywhere near the correct rating anyway. Sometimes you get what you pay for. Setting the front right, may make the back look low...because it is. Another thing, no nuts of bolts on the leaf springs, shackles, hangers, control arm bushings, sway bars, or strut rods  should be torqued until the vehicle weight is on the tires. Because bushings will also make the suspension react or sit oddly. Lastly, ona  mopar, caster and camber effect toe. Toe doesnt effect them. So set toe last.

Offline ViperMan

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Re: How 'bout them frames?
« Reply #9 on: April 21, 2007 - 06:10:14 PM »
Yeah I think my front end is too low, but all my parts are shot, so I gotta fix that first.
2000 Dodge Viper GTS Coupe - 8.0L V10, 6-Speed Tremec
2005 Jeep Grand Cherokee Limited - Trail Rated - 4.7L V8, Auto
2010 Dodge Challenger SE Rallye - 3.5L V6, Auto (Wife's!)

Offline Confederate Cuda

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Re: How 'bout them frames?
« Reply #10 on: April 22, 2007 - 05:36:05 AM »
Yeah I think my front end is too low, but all my parts are shot, so I gotta fix that first.
I have the entire front suspension from my 73 that I will sell if you need it but give me a call if you are interested as I may be moving soon. 704-231-4446 Mark