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Discussion Starter #1
What is the best or suggested method to installing subframe connectors? With the suspension installed and weight on suspension (as suggested here by some) or with suspension removed and the body suported in its lifting/jacking locations in all four corners(as I have plans for this weekend)?

Just thought I would see what everyone thinks.

Or is there another suggested way?
 

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You should have looked at the post 9 down from yours. It asked the same basic question and got some good discussion.

Look here

You need the suspension in the car at the very least.
 

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Discussion Starter #3
I have taken an active part in his earlier post about the suspension thing. I posted in responce to some of my post's responces. Which is why he posted it again as a general question. I still dont see why you would need the supsension on the car.
 

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I suppose that if you were to support the car on a jig, just like it would be with the suspension, that it would then flex in the same manner that it would on it's wheels/suspension.

The issue is that the Mustang is a uni-body frame. You don't have a rigid frame to work with. You have the body, which tends to flex under load. If you weld the sub-frames in when the body is not "at rest" with all of it parts in place, then you run the risk of having the uni-body in an unnatural state for the rest of it's life.

Ultimately, it's up to the owner to do what he/she feels is right. It makes no beans to me either way.
 

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Discussion Starter #5
As you said it is up to the owner to do what they wish. However, this site is for bouncing ideas off each other and experiences. That is why we are all here.

In a way you actually make my point. The body is flexable and as such, sitting under its suspension and weight would seem to be a bad place to start. Especially if there is new suspension/springs and an old body. It would seem the flex/stress would be worse.

I would imagine that the subframe connectors, if the subframes are properly alingned, would lock the unibody in its most correct state. All other items, fenders, hood doors and such are all made to be aligned to the unibody.

It just seems that the unibody is the frame and if you strengthen the frame by adding the subframe connectors the body is stronger. If the body flexes before they are welded in you are locking in that flex.

Just my .02
 

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Discussion Starter #6
You know, the more I think about it the more I think you may be correct.

I am not creating a frame for the car only something to strengthen or reduce the flex factor. As such I may be unknowingly creating a frame using the subframe connectors and the subframes. Taking all load off the unibody, causing undo stress on the subframe and subframe connectors.

By George, I think I got it!

I just had to reread all the posts and get off my High Horse for a second or two.

Thomas
 

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You have a point. Normally I would work under the assumption that Ford had designed the uni-body to be "at rest" with all of it's guts installed. However, after 30-odd years all bets are off.

Where does this leave someone wanting to put in sub-frame connectors? Up in the air with a decision to make that will impact the way their car handles for the duration of time that the sub-frames are left in place.

Ultimately you can only do what makes the most sense to you and as I stated before, I would not weld in sub-frame connectors unless the car was fully assembled and resting on it's wheels.

<blockquote><font class="small">In reply to:</font><hr>

subframe connectors, if the subframes are properly alingned, would lock the unibody in its most correct state

<hr></blockquote>The problem with this statement is that we don't really have a way to measure "it's most correct state". As someone else pointed out, the specifications are quite sloppy.
 

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The joy of replying as I get the email...

I just flogged a dead horse in my last response /forums/images/icons/smile.gif

You are correct in that the one thing we are trying to avoid is causing the sub-frames to carry the entire load. It should be a unified effort, shared between the uni-body and the sub-frames.
 

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Man, I am getting scared. I just put mine on last Sunday, and now maybe I did it wrong. I had the rear end on jack stands, and the front torque boxes on stands. also.
I haven't had much of a chance to drive the car much yet. So far it feels great, but, won't know till this weekend. Taking a little road trip. Hope I can keep it between the ditches......
If I have trouble, there is always a torch to remove them with.....I will let you'all know first of the week....
 

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Discussion Starter #11
After my last post I had a discussion with SWMBO. She is an Electrical Engineer that has a great memory for technical things.

After I explained the situation, using a model car to show subframes and such, she agreed with installing them with the weight of the car on teh suspension. And that I am not making a frame only reducing flex on a design that was intednted to carry a load.

I know what you are saying," What would an EE know about cars, cars aren't electrical." Remember, all engineers take a statics class. ( Objects under load ) My SWIMBO made only 4 B's in college and the rest were A's. Statics was one of the A's.

BTW. She makes more than me but that's alright it allows me to support my Mustang habbit.

Thanks again for the advice.
 

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Discussion Starter #12
You know, I dont think what you did is going to be a problem.

My car is a shell and as such has no loads on it. You have an engine, transmission, doors and everything on your car.

As such you already had loads onthe front subframes. Even though there was no weight on the suspension the other things will somewhat load the car.

I am not sure that any of this is going to matter a ton. I dont plan on racing my car and as such only want it a bit stiffer on the road. I cant imagine what you did causing a problem.

Good luck and let me know how it goes.

thomas
 

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My 0.02:

It seems to me that you want the subframes to bear a good deal of the load. I have the TCP ones, and they are MUCH more beefy than my "frame" rails. As someone pointed out in the previous post, "Why flex a weary frame and then weld the connectors on to make it rigid at that point? It seems that welding the connectors on now would prevent, instead of lock in, the sag on your 37 year old unibody."

This totally makes sense. Think about how nearly all of us had to jack the front of our cars up to install the monte carlo bar. Why? because the unibody had flexed out of spec.

Furthermore, in theory you wouldn't want to "lock-in" the extra stress of a fully assembled car, if you could avoid it. Mechanical stresses can literally be added together. But the only way to totally avoid weight stress is to weld it in space, and that might be a bit difficult.

In actuallity, I don't think it really makes that much of a difference. I'm know people have done it both ways, but with the same results.
 

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I have great respect for all engineers, even more so for the women that put up with us guys long enough to get into the profession.

My wife is a financial controller, but has a serious bent toward the physical sciences. Not much help in this sort of discussion, but can turn a screwdriver with the best of them /forums/images/icons/smile.gif
 

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Discussion Starter #15
As with many things on this site people worry about each step of the restoration or assmebly of their cars. These things are expensive and noone wants to make mistakes.

I think the statement Kketell made is a good one. If you are comfortable doing it do it. We are all insecure and want someone to back up our mistakes or ideas.

I have seen many many cars at car shows I was in awe over. Upon talking to the guys at the mustang club meetings, i find out about fiberglassed in cowel areas and hidden pop rivits. Things no one would have ever known was there.

So basicly. If it works it works. As long as the outsidelooks good you will have no problem reselling it down the road.

T
 

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Discussion Starter #17
Thats pretty cool.

Mine wants to test all the wiring harnesses and wire the car. This is going to save me time and $ too. i was planing on just replacing most of them. This will give her more of a sence of doing sometning on the car and really making it hers. She has picked out the colors/options/ engine specifications/ rear gearing and choice of a shelby short hood. But has not been able to do any physical work due to a spinal fusion a few years ago.

My fastback is going to be her car. I gave it to her on her 27th birthday four years ago. She hopes to be riding in it soon. My 69 mach1 waits her cars completion. I am aiming for the beginning of the year.
 

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This is according to Competition Engineering who makes Mustang subfame connectors. This is not word for word, but the instuctions say to leave the front wheels on the ground and raise the rear of the car at the axle until your suspension is compressed. Meaning the car and axle both move up. Then do one side at a time. I did this in my garage with the bolt in ones and then drove the car to get them welded in. No problems...
 

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Thinking about TCP, doesn't their instructions say to do this "once the car is lifted". Wouldn't this mean the suspension is unloaded?
 

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Discussion Starter #20
after sleeping on it i am now confused as ever before. You present my origional point and I still hold out that it makes sence. However, KKETELL also made me look at the other side. I will have to look into it a bit more. I may try to call the manufacturer of the subframe connectors I bought. Since I did not dish out the big bucks for the TCP units I will have to go through my parts vendor first.

Thanks again for adding to the discussion. I am not sure how I am going to install them at this point.

Thomas
 
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