Moving Leaf Springs inward with new subframe connectors

Discussion in 'Classic Mustang Specific Tech' started by nitrous21, Mar 26, 2009.


  1. nitrous21

    nitrous21 New Member

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    Hello all,

    I am about to play with my rear suspension a bit on my 67 coupe and was hoping I could get some advice. Right now I have caltrac monoleaf springs and competition engineering slide-alinks. My current project is installing a pair of weld-in competition engineering subframe connectors. They allow you to move in the leafsprings a few inches, which I would like to do.

    Here is a link to the instructions, the crappy diagrams is on the second page: http://static.summitracing.com/global/images/instructions/cee-3013.pdf

    My question is, if I move the leafsprings to the new location inside the subframe connectors (like 2 or 3 inches), will I need to do any other modifications to the suspension or buy new shocks??? I know I will need to move the spring perches on the diff close together, but will there be a new angle that requires major work to be done to work correctly?

    Thanks all!!!!!!!! :flag:

    Marc G
  2. mtaqua

    mtaqua Member

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    When I moved mine inboard I put them right inside the frame (not 2-3 inches inside the frame). This gave me a pretty big angle on the leafs. In order to make them parallel again I had to make brackets for the rear (crites makes some I wish I'd have used) to move the springs in board in the rear too. I also bought some offset shackles (from moneymaker), which helped align the springs. The brackets were easy, only problem was the floor on the drivers side did not allow for offset bracket & shackle in the rear (I did the passenger side first and had no idea until I went to mount the bracket). I had to extend the floor by about 2 inches and also cut & re-weld the fuel tank by a couple inches. Which caused me to have to make a modified filler tube to line up. Now I don't know if the angle was a bad thing on the leafs, but I didn't like it. My car was a shell, and I am doing major surgery, so I made the springs parallel. I also mini tubed, and put 67 outer wheel wells in(66 coupe). I can fit a 13.5X28 15" tire in there now and it not hang out(and maybe even a 14.5).

    Since the springs are moved in the shock are more straight up and down. So I had to reshape the shock mount in the body with a propane torch and BFH. You probably also have to bend the tab up on the slide-a-links to allow for the new angle.

    I think it would have been better to cut the frame out and put a mount for the leaf spring in there. Have the leaf go into the frame instead of on the inside. If I were to do it again I'd think about that. Probably could have gotten away with just offset shackles in the back then (but not sure if I'd have the tire clearance, but worth checking).

    You can do a search under my user name and look at some of my post on the subject.

    Andrew
  3. fastcoupe68

    fastcoupe68 Member

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    Leaf springs should not be parallel they should be angled out at the back. If they are not the back end of the car will not track right
    ken
  4. mtaqua

    mtaqua Member

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    Thanks, I guess I should have said closer to parallel than what they were after I moved the fronts in. I moved the fronts from one side of the frame to the other, and the rears from the frame to the inside of the frame. There is still an angle (close to the same angle prior to the mod), but not like it was before I moved the backs too. Is to much angle a problem? I assumed it would be, would have been nice not to worry about moving the backs of the springs too.
  5. fastcoupe68

    fastcoupe68 Member

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    To much angle is not a problem as much as the leafs being parallel This is the reason when you buy a relocation kit and you relocate the front mounts to the inside of the existing rails which generally move the springs in about 2.5 to 3.0 inches or so and all they supply you with for the rear are those offset shackles. Unfortunatley these kits are for brand x and there seams to be nothing for mustangs (classic) specifically so your stuck with what they give you. There are lots of guys w/mustangs running the mopar setup w/no problems so you will be just fine
  6. fastcoupe68

    fastcoupe68 Member

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    I dont know if you have started your project yet but I have a few pointers if you are going to use the comp engineering weld in connectors.
    If you read there instructions included with the weld in connectors they say you must use there formed frame rails to do so.
    1. Your comp slide a links if they are anything like cal trac bars are not going to fit into the new spring pockets. The spring pockets are set up to have there frame rails welded to them.
    2. They also say when you put the sub frame connectors in place to make sure they are parallel to the pinch weld on the bottom of the rocker panels. When you put the comp sub frame connectors in the way they tell you to do they will not be parallel to the rockers no matter what you do. I had to modify a set (cut the front bracket off bolth connectors and use the driver side on the passenger side and vice versa) and re weld both. I did all this to get the spring pocket to be straight when its mounted and the connectors to also be parallel with the rockers which isnt as important as the spring pockets being straight. I think comp eng needs to redo there inst. as far as I'm concerned.
    3. As far as the rear spring mounts I copied crites relocation kits rear mount and made my own rear mounts.
    I hope I did not just confuse the heck out of you but when I did this on a 68 coupe and we used the comp sub connectors this is what I had to do.
    ken

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