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Rear Spring length

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  • Rear Spring length

    Put a Camero rear axle in my pickup with a model A spring on top of it. I then removed some leaves to lower the rear, but now on a big bump, the spring has increased in length so much that the end of the spring hits the axle housing. Are their any shorter springs available that still fit over the differential housing, off the shelf? I know I could have the ends of mine cut and re-curled, but it is an original, and probably getting weak anyway. With so much arch, it doesn't take much lowering to affect the length a lot. I suppose I could just switch to coil overs, but then I'd also need a Panhard bar...
    CB the Wonderful

  • #2
    I guess you had to weld shackle brackets onto your Camero diff?

    Is it too hard to cut them off and move them out a bit?


    • Corley
      Corley commented
      Editing a comment
      There is just no room left for the welded brackets to allow moving them further out. They take up about an inch oneach side before the backing plates. I've thought about making something that connects to the sides of the axle tube to regain that inch, but a shorter spring would work better.

    • pooch
      pooch commented
      Editing a comment
      Just curious, what angle are your shackles on now at normal ride height ?

  • #3
    How about springs on the shock along with the model A spring.


    • Corley
      Corley commented
      Editing a comment
      The big problem here is the huge bang when the spring hits on it's end against the hanger. I'd really like to lower it another couple inches, but that would make the current spring even longer, and bang quicker. If I go to coil overs, I'll need to remove the leaf altogether.
      Last edited by Corley; 06-14-2018, 09:28 AM.

  • #4
    I think the idea of moving the spring perches to the rear of the tube would be the best but depending on how much you move the rear end forward, you may need to cut down the driveshaft.

    Have you looked into the length of the model T rear spring? You may just need to replace the main spring with the model T.
    "We do not stop playing because we grow old;
    We grow old because we stop playing ...
    NEVER Be The First To Get Old!" Pilfered from the MAFC SA Newsletter



    • #5
      Posies has different length model A springs. I had the same problem on my roadster-shackles hitting housing with a stock Model A spring. Got the shorter spring and its perfect. Give them a call, they are great to talk to and help. measure the distance center to center on the perches.

      They are stout,I think I took the top 3 leaves out. They told me never take out any lower leaves. You can break or bend the spring.

      Last edited by john in illinois; 06-15-2018, 01:21 PM.


      • #6
        Great info John for all of us with modified rear ends.

        Looks like this is the ticket..

        If the standard A is 48 1/2 inches, this is one inch in on each side, prob be a straight bolt in deal to fix the problem.
        29-31R-C ’28-31 Model A Narrowed Rear Spring, 46 1/2″ Perch Centers


        • #7
          Fantastic, exactly what I need. Thanks all, especially John in Illinois.
          CB the Wonderful


          • #8
            I'm not well versed in the Modified dept for these early cars. It's great to just sit back for a change and learn from the experts here. This modified area is going to be popular, I can sense it.
            2 1930 Tudors

            Henry Ford said
            "It's all nuts and bolts"

            Mitch's Auto Service ctr


            • #9
              I just went down and measured mine , it is a reversed eye Model A spring .

              Although I flattened it a bit cold in a shop press and removed some leaves.

              At this ride height, it is 3 ft 10 1/2 inches wide .

              I was lucky, my shortened diff using 2 stock short axles just left enough room for the hangers.

              I reckon this is about as low as I could get it without stepping the chassis.


              • Corley
                Corley commented
                Editing a comment
                I can see from this pix that you are about 2-3" lower than I am, good job there making it all fit in that amount of space. For me, there is always a bit of Hope and prayer that the spring is strong enough, but not too stiff, as it's hard to determine exactly what you will need ahead of time.

                I really like what you did on the upper links of the 4 link, getting them up inside the frame. Not much room to get the rumble out there! Nice work for sure. But, what's with the dust? You mean to tell me you drive that??? Ha! Driving these toys is what it's all about for me...

                Question? You say you flattened cold on shop press, did you bend it at a couple spots near the middle, accross a 6" - 8" flat steel plate, or how did you go about that? How many tons did that require? I suppose press it a bit, check it, go some more if needed, then the other side. Not sure if my little 20 ton press is up to it. I also suppose, stay away from the middle where the hole is located. Did you do all leaves, or just 2-3 of them?
                Last edited by Corley; 06-16-2018, 09:45 AM.

            • #10
              Gday Corley, yep this gets driven a lot.

              All 4 links are ford radius rods, althought the top ones did not need to be as they are not seen, but I had some already cut.

              They are triangulated a bit, and I did not fit a panhard bar, thought I would try it, and it does not need one.

              The top brackets only just miss the rumble floor on full bounce.

              Spring leaves bend easy.

              I only have a 6 tonner, prob spread over about 4 inches and tweak it just a bit until you see it just go past the point of springing back and move it along about 2 inches and keep working.

              Mark your spring with a chalk mark on floor, so you see how you are progressing.

              Yep, and keep right away from hole.

              I guess I did a few leaves, don't know which ones, just a bit of a guess, and trial fit.

              Mine just happened to be a good height first go.

              Shackles ended up close to 45 degrees.

              Ride is a bit stiff, because of the tyres I have I think, so next job is to remove spring and clean, grind any divots, and paint and slip plate it.


              • Corley
                Corley commented
                Editing a comment
                Good info here Pooch! I'm surprised 6 tons did the trick, even at almost 80 years old, I learn new stuff every day. Curious as to what material you will use for slides/slip plates.

                They say on any home built hot rod type vehicle, it takes 3 times, (original and 2 rebuilds) to get it just perfectly as you want it, in my case it never ends. I'm on #3 on this rear spring deal right now. Ha! You know, maybe your angled upper links are keeping the rear end firmly centerred, so no banging on the end of the spring. I am only relying on the spring to control side to side movement. Maybe, just maybe, I just need to add a Panhard to keep the rear end centerred. Never really gave that any thought until now. At rest, my shackles are not quite 45 degrees, but close.

            • #11
              If you needed a panhard bar, it would be obvious, when you quickly move the steering side to side at about 25 MPH, you will feel the rear end wallow sideways like a drunken sailor .

              How about posting a pic of your rear end , and let us know how far you have between the spring shackle coil and the hanger .

              And how is your diff located?

              4 link/ radius rods/whatever?

              Have you tried getting a couple of hefty guys jumping up and down on chassis and see what is happening?

              I was justgoing to blast/smooth/paint and try that slip plate stuff.

              I guess it's a type of graphite grease? dunno.

              Corley, kudos to you at 80 and still building hotrods, were you always a hotrodder, or did you come over to the darkside later on in life?


              • #12
                I'll try to get a pix or two up. I've been busy with rattle cans. Just completed a 3 plus 4 overhaul on an 8N Ford tractor, (3 cans of red, 4 cans of light grey), and disassebly for painting of a go cart I just built for the grandkids. Also just completed reassembly after painting of a drift trike I built for myself. It was going to be for the grandkids, but it is too fast and tricky for the little ones to ride. (If you ever build a drift trike, here is a tip. Wear long pants when you are drifting, as it only takes your leg rubbing that big wheel for a second to create a nasty liession on your otherwise pristene body. But man, it sure is fun!)

                Sorry for that diversion, I spent some time staring at my A rear spring and thinking, and now I'm thinking maybe I can modify the hangers and get more open space for spring end clearance. (Sometimes I sits and thinks, sometimes I just sits.) The spirit needs to move me into action now. Since my once half decent welding skills have begun to waver, what with crappy eye site and unsteady hands, I have to make sure I can accomplish something safe now, not necessarily pretty. (Or were those half assed welding skills? Either way, the grinder is my friend now days when it comes to pretty welds.)
                CB the Wonderful


                • #13
                  Solved (I think). The spirit moved me yesterday, and after laying under the back of the PU for a while, I decided to put a vertical support from the backing plate mounting pad over to the shackle thingy. With this new support, I could then cut away the shackle mount enough to get 1/2" more clearance on the end of the spring. I've been putting off doing something about this, and living with the occasional bang when the end of the spring hit the mount for a few years now, I decided it was time to act, and had the job done in about an hour. Good on you guys for motivating me to do something about this lingering problem.

                  After reflecting on it (big word for thinkin'), I decided that since my hangers were at about 45 degrees, a shorter spring would be a killer to spread and connect, and I could "fix" the problem as I mentioned. Plus, it was $300+ cheaper to do as I did. Anyway, it's back to other more pressing issues now, like scraping the pitch off of the Mercedes SL I left under my new shop apron cover. (Hot day, new lumber, drip drip drip goes the pitch.) OR, I could just take a nap, I excel at those.
                  CB the Wonderful


                  • #14
                    CB, show us a pic of what you did.


                    • #15
                      Here is a link to a really interesting topic with pictures at various stages of lowering an A. Lot's of good info here! Hope this does not violate any forum rules!

                      There may already be a thread on this, but I wanted to show what to expect when lowering an A.

                      Link to thread

                      Last edited by Corley; 07-19-2018, 11:18 AM.
                      CB the Wonderful


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