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Discussion Starter #1
Happy Friday the 13th folks! I normally try to avoid such superstitious notions, but I just found out today my bird had a major problem that can't easily be corrected. Seems the passenger side wheel base is a full 1/2" shorter than the drivers side. This is leading to alignment issues and funny handling.

So here is where I am in need of some advice. I can go a couple directions with this. I could part it out and buy my boss's 91 Camaro convertible. I borrowed it recently, and I really like it. To top it off, it is being offered at a very nice price.

I could get a 99-04 Mustang with engine problems and transplant my mill in there.

I could also get a 96-98 GT and use all the motor goodies I have to upgrade it. I even found a GT shell with low miles in my area.

I could try to find another rust free bird (in New England, not easy) and put all my stuff on it. Keep in mind I already did this once when I ruined my 95 SC. All those goodies are on my car now.

Ultimately, I want a 5-sp car. I even started accumulating parts to convert my current bird.

The problem is I know my car hasn't been in an accident since the last alignment I had. I just replaced the lower control arms and everything, which is how I learned of this problem. I'm afraid it has more to do with a tired chassis than anything. The old girl has 353k on the clock.

I can also say I am VERY happy nobody bought my car when I was attempting to sell it. Had I learned this after the sale, I would have felt terrible.

Anybody have any words of wisdom? I just feel sick to my stomach. I have done so much work on this car.

Oh, and don't ask for parts yet. I will let you know when I am ready for that. :(

Thanks,
Nate
 

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Honestly that sounds like a correctable caster problem. What condition are the strut rod bushings in?
 

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Discussion Starter #3
I actually just got off the phone with my mechanic again. He is a good friend of mine, and also build race cars, so he is very knowledgeable on chassis setups. Turns out many of the measurements are off on the rear cradle, which they tried to compensate by adjusting the strut rods. Every bushing in my car is new, I have replaced everything. I spared no expense.

He is suggesting unbolting the rear cradle a little and seeing if he can rotate the cradle to get it to straighten out. I have never unbolted the rear cradle before, so I am not too sure what to expect here, or how much play there is when it is unbolted.
 

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If the car hasn't been in any accident, then that definitely sounds like just an alignment issue, or worn out strut rod bushings. Many chain places that do alignments just set the toe because on most newer fwd cars, that is all that is adjustable. If your strut rod bushings are good, find a good alignment shop that will make all the adjustments to your suspension, both front and rear, and if they can't get it right, post back here with the alignment measurements, as well as measurements from the tire to the wheel well both front and back, and hopefully we can help you figure out what the problem is before you go parting out a perfectly good car.
 

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Discussion Starter #5
I will see if I can get some measurements. On the alignment shop, it is one of those small places, this guy is really good. I've used him before, and has corrected the problems a chain store caused...

On the strut rods, one of them is tightened all the way down, and the other is only showing 2 threads or so. The main problem is there is no more camber (I think) adjustment because of this, and is on the outer edge of being in spec. The alignment guy did this just to make as straight as possible, but it really acts funny. It's a strange combo of loose and tight at the same time...
 

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Discussion Starter #6
As it turns out, I have a friend with a frame machine. I am gonna pull some strings. There is hope yet. I just wish I knew why it was off!

Nate
 

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Discussion Starter #7
Friend with the frame machine is being strange and basically telling me no. Ugh.

My mechanic says that he is pretty sure the problem lies within the rear cradle. I have never removed one personally. What I would like to know is if he loosens up the bolts on the rear cradle, can we twist it a little? Is there any room for adjustment there?

Thanks,
Nate
 

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Not really, certainly not 1/2" worth of movement, and if you have not taken it out and reinstalled it, or hit anything, then it isn't going to move in the first place. Before anything, takes some measurements at all 4 corners between the wheel and the front and rear of it's wheel well. One of those will be off compared to the opposite side, and that will tell you whether the problem is in the front or in the rear. My suspicion is the problem is on that front wheel that is almost out of adjustment on the strut rod.
 

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I had this issue with my 94 bird... the left front wheel was closer to the back of the wheel well.... its a very simple adjustment. All I did was measure the passenger side and adjusted the drivers side to be the same. Frames do not bend or warp on these cars or on any vehicle unless they have been in a wreck.
 

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borf42 said:
FMy mechanic says that he is pretty sure the problem lies within the rear cradle. I have never removed one personally.
It's possible your rear subframe has gotten a little tweaked over the years of abuse..

It's not really difficult to swap out rear subframes unless of course everything is crusted, and rusted together..

All years of MN12 rear subframes are the same AFAIK..

I've personally never heard of anyone using a frame staightener on the MN12 IRS Subframe..So I'm not sure straightening it is even possible.. :zdunno:

It's pretty easy to tweak one of these rear subframes with an aggressive driving style..

That's why when mine comes out it's getting welded up like they did in this Tech Article--->>IRS Build-Up How To



Rayo..
 

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There is plenty of play available to account for the wheelbase difference on the passenger side. I have the rear IRS subframe out right now. The threaded washers inside the rear frame rails that the 4 main subframe bolts go into have enough space inside the frame rails to move about ± 3/8" forward/backwards. Not only that, the short stamped steel plate on the front portion of the subframe (the one that also attaches to the frame rails via two smaller shorter bolts) has elongated bolt holes (front-to-back) as well.

STEEL PLATE



FOLLOWING TWO PICTURES, REAR OF THE SUBFRAME




FOLLOWING TWO PICTURES, FRONT OF THE SUBFRAME







Whether or not this is the problem is up in the air, but there it is.
 

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As you have it laying there; whats the maximum angle of deflection from normal, each way, based one the separation of the right and left bolt locations?
 

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As you have it laying there; whats the maximum angle of deflection from normal, each way, based one the separation of the right and left bolt locations?
angle of deflection of what part? the whole IRS subframe? what is "it"?
 

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the whole IRS subframe? what is "it"?
Yes, the subframe is what we were talking about; I could have been way more clear, tho.

I have a wiggly rear on Lazarus; DLF's kit is going in next week. :)

I wondered how far it can go, from side to side; that movement shows up as a power-dependent steering input. :D

It (Lazarus) wants to bear left under hard acceleration; that's not good. It's off the road tillit gets fixed, parts are on order from RA. :)

("tillit" is a TN unit of indefinite time; similar to "dreckly", as in "i'll get to it directly". :) This now means a distinct time, thet is sometime between now and the time the last proton in the universe decays into nothingness.)

:)
 

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I have a wiggly rear on Lazarus; DLF's kit is going in next week.
Wish i would have bought those while i had the chance. Not to get off topic, but Ive got mine out too right now. Has anyone used the aluminum bushings off scp for the subframe mounts?
 

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Discussion Starter #16
Guitar Maestro,

Thanks for those pics, you are giving me some hope! I really hope that fixes it. I will likely hear from my mechanic tomorrow on how the adjustments went. I had the JL subframe connectors installed by a friend of mine, looks like it got messed up then. I took these pics right after they were installed:



Check out how much it moved from where it was for years (Mount is the two bolts on the top right of the pic). Hopefully this gets my car back on track.

Nate
 

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Discussion Starter #17
Good news! The rear subframe was moved when the subframe connectors were installed. My mechanic was able to correct the severe demensional problem with the bird. The bad news, though, is that a welded nut in the subframe of the car was cross threaded and broke, and was a flex point as well. So, it happens to be a nut super close to the gas tank. My mechanic said he is braver than most when it comes to welding, but he is not gonna do that. He is gonna drop the tank. Shouldn't be much effort, as I dropped that tank several times tracking down a leak. Tim's car spent its life in Florida, so it is super rust free underneath. Makes it easy to work on. We are hoping to have it ready for the autocross in Hartford Sunday!

Again, thanks for all your help guys. That TR-3650 swap is back on!!!

Nate
 
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