Measuring ride height

Discussion in 'Suspension, Steering and Chassis' started by downsr, Jul 4, 2018.

  1. downsr

    downsr FABO Gold Member FABO Gold Member

    Messages:
    863
    Likes Received:
    463
    Joined:
    Dec 17, 2011
    Location:
    waverly ohio
    Local Time:
    4:12 AM
    Does some one have a close up photo of where to take the measurements for ride height on 70 Duster. Is it from the lower ball joint to floor and adjusting blade to floor. Then subtract the two. What are they meaning by adjusting blade
     
    Last edited: Jul 4, 2018
  2. Bodyperson

    Bodyperson Well-Known Member

    Messages:
    509
    Likes Received:
    204
    Joined:
    Nov 26, 2015
    Location:
    NW Montana
    Local Time:
    3:12 AM
    Adjusting blade raises and lowers the ride height. That description is vague. The measurement is to the blade where it grabs the torsion bar. Directly below the torsion bar where you adjust the ride height.
     
  3. Bodyperson

    Bodyperson Well-Known Member

    Messages:
    509
    Likes Received:
    204
    Joined:
    Nov 26, 2015
    Location:
    NW Montana
    Local Time:
    3:12 AM
    From what I recall, the measurement is to the round part of the lower control arm where the torsion bar enters the control arm. They actually have a tool for that measurement that hooked on the grease zerk of the ball joint and lined up with the area I described with a spring loaded scale.
     
  4. AJ/FormS

    AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

    Messages:
    13,385
    Likes Received:
    3124
    Joined:
    Jan 19, 2014
    Location:
    South-Central Manitoba,Canada, 900ftelevation
    View My Photos
    Local Time:
    4:12 AM
    Ima thinkin that method would only work with oem T-bars, cuz any other bar might result in a different ride height at the same blade measurement.
    I put it into my memory banks years ago that it was the vertical difference between the center of the T-bars and the centers of the LBJs. That works for all bars.
    But think about what this spec does; it attempts to put your front end in the center of the camber curve, that minimizes bump steer due to camber changes when the left and right sides of the car are at different ride heights; as in a turn, or bumping over rutted roads. Of course this all goes out the window if your strut-rod bushings are like jello.
     
    • Thanks! Thanks! x 1
    • harrisonm

      harrisonm Well-Known Member

      Messages:
      1,701
      Likes Received:
      972
      Joined:
      Jan 16, 2005
      Location:
      Topeka, KS
      Local Time:
      10:12 AM
      I have an old shop manual with good pictures of this. I'll post them tomorrow.
       
      • Like Like x 2
      • Thanks! Thanks! x 1
      • downsr

        downsr FABO Gold Member FABO Gold Member

        Messages:
        863
        Likes Received:
        463
        Joined:
        Dec 17, 2011
        Location:
        waverly ohio
        Local Time:
        4:12 AM
        I am still confused on where to take the measurements. Can not find any good pictures.
         
      • Jim Lusk

        Jim Lusk Well-Known Member

        Messages:
        3,773
        Likes Received:
        266
        Joined:
        Mar 8, 2006
        Location:
        Fresno, CA
        View My Photos
        Local Time:
        2:12 AM
        I have never liked the factory height method. Maybe it is easy on an alignment rack, but a pain on a garage floor. I set height with about an inch between the LCA bumper and frame. Then I measure from the frame to the LCA using the same point on both sides and making them even. This is a little lower than the factory setting. Torsion bar size has no effect on measuring ride height.
         
        • Agree Agree x 1
        • AJ/FormS

          AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

          Messages:
          13,385
          Likes Received:
          3124
          Joined:
          Jan 19, 2014
          Location:
          South-Central Manitoba,Canada, 900ftelevation
          View My Photos
          Local Time:
          4:12 AM
          And I'll add; make sure you don't have one saggy spring in the back, cuz tha will mess you up
           
        • 1969383S

          1969383S FABO Gold Member FABO Gold Member

          Messages:
          3,460
          Likes Received:
          989
          Joined:
          Jan 8, 2012
          Location:
          Cumming, GA.
          View My Photos
          Local Time:
          5:12 AM
          With some of the above comments to consider. If “all” the suspension pieces are in good working order it is very simple.

          Measure from the floor to the adjusting arm at the flattest point on the inner side of the adjuster bolt. This is the A measurement. Measure from the floor to the bottom of the lower ball joint case. This is Measurement B. The measurements should be no more than 1/8th difference. It does not matter what size tire diameter or what size bar is installed! This is the procedure for all cars regardless of tire/wheel size or bar diameter. I find it easier to put some bricks or such on the floor and place my 6’ level across them and confirm level. It is easier to measure down to the top of the level when doing it this way. Course if you have access to an alignment rack all the better. MaPar designed our cars this way to be simple and only one adjustment procedure for all the bodies, engine sizes and bars. They pre-engineered it that way. This will center the upper/lower arms between the stops and set the correct angles in the suspension as well as load the “pre-engineered” bars to the correct value. All this said, it is the procedure for stock Mopar components and the aftermarket may not have engineered this into their products. Further more if you are jamming a 440 in an Slant six equipped A body then use the correct bars and so on.
           
          Last edited: Jul 23, 2018
          • Thanks! Thanks! x 1
          • Bodyperson

            Bodyperson Well-Known Member

            Messages:
            509
            Likes Received:
            204
            Joined:
            Nov 26, 2015
            Location:
            NW Montana
            Local Time:
            3:12 AM
             
            • Thanks! Thanks! x 1
            • downsr

              downsr FABO Gold Member FABO Gold Member

              Messages:
              863
              Likes Received:
              463
              Joined:
              Dec 17, 2011
              Location:
              waverly ohio
              Local Time:
              4:12 AM
              Thanks for all the info.Hard to get measurement on ball joint to floor because of inside of rim
               
            • Bodyperson

              Bodyperson Well-Known Member

              Messages:
              509
              Likes Received:
              204
              Joined:
              Nov 26, 2015
              Location:
              NW Montana
              Local Time:
              3:12 AM
              Hence the tool I mentioned.
               
              • Thanks! Thanks! x 1
              • Bodyperson

                Bodyperson Well-Known Member

                Messages:
                509
                Likes Received:
                204
                Joined:
                Nov 26, 2015
                Location:
                NW Montana
                Local Time:
                3:12 AM
                You could run a elastic string between the ball joints and measure from there to the torsion bar.
                 
                • Thanks! Thanks! x 1
                • AJ/FormS

                  AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

                  Messages:
                  13,385
                  Likes Received:
                  3124
                  Joined:
                  Jan 19, 2014
                  Location:
                  South-Central Manitoba,Canada, 900ftelevation
                  View My Photos
                  Local Time:
                  4:12 AM
                  Lacking the tool,
                  you can remove one front wheel and but a block under the rotor or spindle with the suspension relaxed and the car leveled from side to side. But it is as good as impossible to relax the suspension using this method, as the side with the tire still on may need to be stretched towards the outboard. But you can get a close approximation if you drop the tire pressure to about 10 psi, and re-level the car. The low pressure will allow the sidewall to deflect under the pain of the tire being too far towards the inside. .
                  Alternatively you can use a wheeled floor jack under the rotor, and jounce the car a time or two, allowing the jack to be the relaxer, as it rolls from outboard to inboard. With the wheel gone, it is also easier to do the measuring.
                  Just don't let the car roll off the jack with you under it!
                   
                  • Thanks! Thanks! x 1
                  • downsr

                    downsr FABO Gold Member FABO Gold Member

                    Messages:
                    863
                    Likes Received:
                    463
                    Joined:
                    Dec 17, 2011
                    Location:
                    waverly ohio
                    Local Time:
                    4:12 AM
                    Where can you get the tool bodyperson
                     
                  • 72bluNblu

                    72bluNblu FABO Gold Member FABO Gold Member

                    Messages:
                    8,620
                    Likes Received:
                    2579
                    Joined:
                    Nov 28, 2008
                    Location:
                    NorCal
                    Local Time:
                    2:12 AM
                    Here's another version of the picture, with the description for setting the factory ride height and the actual specs. The "V&L" line shows the A-body specs. Like the other picture it shows the measurement being taken at the bottom of the adjusting blade, which is on the round section, not out at the torsion bar adjusting bolt. So the angle of the blade being different for a different sized torsion bar shouldn't matter.

                    factoryalignspecs.jpg

                    The other thing is, the factory ride height only provides the best suspension geometry if you use bias-ply tires. If you're using radial tires, the factory ride height specs will NOT give you the best geometry, camber curves, etc.

                    Just like the static alignment specifications are different for bias ply tires vs. radials, the camber curves, caster changes, etc, are different for radial tires. Think about it. Bias ply tires use specs that are almost opposite for what you want for radials- bias ply alignment specs use positive camber and negative caster. Radials use negative camber and positive caster for the best handling characteristics. The factory ride height takes that into account, it minimizes negative camber gain. Which is what you want for bias ply tires. But it's exactly the opposite of what you want for radials, you WANT negative camber gain on an ideal radial tire camber curve, it will provide the best handling.

                    Now, you don't have to set your car up for the best handling, that's totally up to you. And most people set their ride height based on the best appearance (in their opinion anyway), not necessarily the best performance or suspension geometry. And that's true at both ends of the ride height spectrum.

                    But, the idea that using the factory ride height is "best" because that's what the engineers designed for is totally mistaken. The minute you put radials on your car instead of bias ply's the factory design and settings being best goes out the window, because that's not what they were designing for, and not what the factory specs are set for. If you run radials, using the factory specs for alignment and ride height will not give you the best performance.
                     
                    Last edited: Jul 24, 2018
                    • Thanks! Thanks! x 1
                    • Bodyperson

                      Bodyperson Well-Known Member

                      Messages:
                      509
                      Likes Received:
                      204
                      Joined:
                      Nov 26, 2015
                      Location:
                      NW Montana
                      Local Time:
                      3:12 AM
                      I do not know. Obsolete. Another thing that could work is a straight piece of square tubing cut to the width of your ball joints and notch it for the grease zerks. The best advise comes from 72bluNblu
                       
                    • downsr

                      downsr FABO Gold Member FABO Gold Member

                      Messages:
                      863
                      Likes Received:
                      463
                      Joined:
                      Dec 17, 2011
                      Location:
                      waverly ohio
                      Local Time:
                      4:12 AM
                      When they refer to adjusting blade are they meaning the bottom of the housing where the torsion bar goes in the lower control arm. Anyone have a pic of the adjusting blade
                       
                    • 1969383S

                      1969383S FABO Gold Member FABO Gold Member

                      Messages:
                      3,460
                      Likes Received:
                      989
                      Joined:
                      Jan 8, 2012
                      Location:
                      Cumming, GA.
                      View My Photos
                      Local Time:
                      5:12 AM
                      Across the red line.

                      28CDE12D-7FAE-41A4-AAF7-4C73B97D3837.jpeg


                      More specifically right here.

                      9D981B12-3BF4-4EEC-86A1-39E2444AB562.jpeg
                       
                      Last edited: Jul 28, 2018
                      • Thanks! Thanks! x 1
                      • Johnny Dart

                        Johnny Dart Well-Known Member

                        Messages:
                        7,033
                        Likes Received:
                        912
                        Joined:
                        Nov 30, 2006
                        Location:
                        So Cal
                        Local Time:
                        2:12 AM
                        I just measure from the garage floor, to the bottom of the fender. Then match the other side.
                        Find the height to your taste, and your good.

                        PS: Before adjusting the torsion bars, loosen the 2 lower control arm nuts a couple turns.
                        This will stop you from tearing the bushings in the control arms. Tighten them back up after you adjust the height, and the car is on the ground.
                         
                        • Thanks! Thanks! x 1
                        • Agree Agree x 1
                        • 1969383S

                          1969383S FABO Gold Member FABO Gold Member

                          Messages:
                          3,460
                          Likes Received:
                          989
                          Joined:
                          Jan 8, 2012
                          Location:
                          Cumming, GA.
                          View My Photos
                          Local Time:
                          5:12 AM
                          To each his own.

                          The fenders would not be my choice as you are not setting it correctly.

                          If you first set the static height with the nuts loose and need to make minor adjustments down the road there is no need to loosen the pivot nuts again. If you are adjusting inches or more than, by all means loosen the nuts on the pivot first. If it had already been done correctly and that much adjustment is required then one must look for other issues.
                           
                          Last edited: Jul 28, 2018
                        • 1969383S

                          1969383S FABO Gold Member FABO Gold Member

                          Messages:
                          3,460
                          Likes Received:
                          989
                          Joined:
                          Jan 8, 2012
                          Location:
                          Cumming, GA.
                          View My Photos
                          Local Time:
                          5:12 AM
                          If you need more caster/camber help then use the offset upper arm bushings from MOOG to get you there. Adjusting ride height to get this, changes much more to the negative.
                           
                          • Thanks! Thanks! x 1
                          • Jim Lusk

                            Jim Lusk Well-Known Member

                            Messages:
                            3,773
                            Likes Received:
                            266
                            Joined:
                            Mar 8, 2006
                            Location:
                            Fresno, CA
                            View My Photos
                            Local Time:
                            2:12 AM
                            The fenders are not necessarily the same height off the frame, so that's not a real good point to use.

                            As long as the frame is not sitting on the LCA bumper there is no need to loosen the nut. The LCA rotates around the torsion bar socket.
                             
                            • Thanks! Thanks! x 1
                            • Johnny Dart

                              Johnny Dart Well-Known Member

                              Messages:
                              7,033
                              Likes Received:
                              912
                              Joined:
                              Nov 30, 2006
                              Location:
                              So Cal
                              Local Time:
                              2:12 AM
                               
                              • Thanks! Thanks! x 1
                              • Bodyperson

                                Bodyperson Well-Known Member

                                Messages:
                                509
                                Likes Received:
                                204
                                Joined:
                                Nov 26, 2015
                                Location:
                                NW Montana
                                Local Time:
                                3:12 AM
                                Pretty sure Jim knows that these Mopars have Unit Body FRAMES. And that the FRAME rails are unitized into the body. And that unit body frames has been shortened to be called Uni-Body or as most people spell it "unibody"