Announcement

Collapse
No announcement yet.

Caster Issue...how to fix Radius Rods? or Control Arms?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    #16
    Some great technical information in here


    UKDM 93 CB3 Page (1) H22A U2Q7 LSD
    UKDM 91 4ws Page (3) OEM Minter
    NOW H22A U2Q7 SWAPPED

    Comment


      #17
      Originally posted by marcusv8thunder View Post
      Some great technical information in here
      As far as it goes. The interactions between the various geometries are complex and hard to describe, even if you fully understand them (which I don't claim to).

      Steering pulls (that aren't tyre related) are typically caused by forces acting around the steering axis, when these forces are unbalanced side to side on the car (and even if the pull is caused by the tyres, if you look into it deeply enough the tyres are creating unequal side to side forces to be fed into the steering axis). If we consider the steering axis to be a pivot (which it effectively is), and the centre of the contact patch to be where loadings are applied to the pivot, then force created at each contact patch acts both laterally and longitudinally on the steering axis. 'Trail' and 'scrub radius' both act as effective lateral and longitudinal 'lever arms' that leverage the forces (generated at the contact patch) into the steering axis.

      A proper explanation (or at least as best as I could explain it) would require several thousand words, and would be confusing (both to read and to write), but suffice to say if the 'lever arms' (trail and scrub radius) differ in length side to side then a steering pull may result, but if scrub radius is zero then it probably won't.

      The thing is, while scrub radius may be X on the drawing board, in reality it effectively changes all the time depending on road surface camber, wheel camber, and lateral loading on the tyre. So, a steering pull could be a constant thing, or could be momentary. Momentary steering pulls are what the driver interprets as steering 'feel'. A side to side asymmetry in the 'unsteered' lever arms (trail / scrub radius) is what causes a constant pull when travelling over a consistent surface.

      A 'pull' can also be an artefact of a problem in the steering mechanism, particularly PS where the spool valve is giving more assistance left vs right.

      Regards,
      John.
      Last edited by johnl; 03-06-2015, 08:49 PM.
      Regards from Oz,
      John.

      Comment


        #18
        Well I found out nothing was bent, had spare radius rods in my garage to check them with. Also, the OE strut rod bushings were in perfect shape, no stress cracks or anything, even better and more pliable then the O'Reilly masterpro replacements. But, they were crushed moreso than the new ones for being in there for 23 yrs. Should I replace them?

        The driverside rod had 1 washer and the passenger side had 1 washer, so it looks like I just need to add 1 washer from the passenger side to give the driver side to give it more negative caster to equal out the passenger side right?

        So if each washer is worth .5 degrees, I should end up with 1.3 on the driver side and .9 on the passenger side.

        Or do you recommend putting in the new bushings which are thicker and made of a harder rubber plastic? And leaving everything and see what effect that has?

        member's ride thread
        93' EX Coupe H22A w/ P2T4 Sir 5spd 191whp 155 wtq
        99' Lexus LS400 157k VVTi V8 gets up & goes...new DD
        91 Accord SE 176k
        97' Honda Odyssey 199k miles...$485 spare van for my parents

        Comment


          #19
          It looks like the minimum acceptable caster per my Helms manual is 2 degrees, I can achieve that on the driver side by removing the washer, but if I remove the washer on the passenger side, it only brings me to .8 degrees.

          Should I try a more drastic approach and unbolt my front crossmber and see if I can pull it forward on the passenger side to bring my caster angle more positive?

          Last edited by Losiracer2; 03-07-2015, 12:52 AM.

          member's ride thread
          93' EX Coupe H22A w/ P2T4 Sir 5spd 191whp 155 wtq
          99' Lexus LS400 157k VVTi V8 gets up & goes...new DD
          91 Accord SE 176k
          97' Honda Odyssey 199k miles...$485 spare van for my parents

          Comment


            #20
            Here are the pictures of my strut rod bushings:

            Driver side on Right, Pass side on Left


            Pass. Side Bushings




            Driver side Bushings



            member's ride thread
            93' EX Coupe H22A w/ P2T4 Sir 5spd 191whp 155 wtq
            99' Lexus LS400 157k VVTi V8 gets up & goes...new DD
            91 Accord SE 176k
            97' Honda Odyssey 199k miles...$485 spare van for my parents

            Comment


              #21
              Originally posted by Losiracer2 View Post
              Well I found out nothing was bent, had spare radius rods in my garage to check them with. Also, the OE strut rod bushings were in perfect shape, no stress cracks or anything, even better and more pliable then the O'Reilly masterpro replacements. But, they were crushed moreso than the new ones for being in there for 23 yrs. Should I replace them?
              If the rubber is still good but somewhat compressed, then it's not unlikely to be stiffer than it was when new (which should be a good thing). If they appear otherwise OK (other than being shorter) then I can't see a reason not to re-use them, but, as noted they are shorter, negating any benefit of the increased stiffness (the 'pre-load' will be less, meaning they will act more or less as if the rubber were less hard, because the pre-loading is less). To re-fit them with the same compressive 'pre-load' (as new), you would need to shorten the crush tube by the same amount as the rubber has compressed.

              Of the two bushes (per rod), the longer one is softer because it has a longer length of rubber. With mine, I shortened the longer of the two bushes to match the length of the shorter one. This makes the shortened bush as stiff (or even somewhat stiffer) as the shorter bush. I say "even somewhat stiffer" because the 'void' in the bush (i.e. the concavity in the end face of the bush) is less deep on the shortened bush (than on the originally short bush) once the shortened bush has been shortened. So, after shortening there is more rubber in the shortened bush than in the originally shorter bush, so the shortened bush will be somewhat stiffer than the already shorter bush (if you can follow my poorly expressed meaning...), .

              To make this work the crush tube has to be shortened to fit the now shorter length of the combined two bushes. With my car, I added additional washers that pass over the crush tube (washer ID slightly larger than crush tube OD) to apply additional pre-load to the bushes, so that as a result they are effectively stiffer. This could also be done instead of shortening the crush tube as above.

              Originally posted by Losiracer2 View Post
              Should I try a more drastic approach and unbolt my front crossmber and see if I can pull it forward on the passenger side to bring my caster angle more positive?
              The sub-frame has somewhat over sized bolt holes that allow it to be moved longitudinally and laterally once the bolts are loosened. This fact can be used to adjust caster and to equalise camber angles. Before loosening the bolts, mark the chassis and sub-frame carefully so that you have initial reference points, i.e. so you know how far forward / backward or sideways you may have moved the sub-frame from it's original position.

              You'll need three pairs of reference marks (a pair being one mark on the sub-frame and one on the chassis), one pair of marks each for 'lateral' and 'longitudinal' on one side of the car, and one pair of marks on the other side for 'longitudinal'.
              Regards from Oz,
              John.

              Comment


                #22
                Correction. I've been working too much on the Saab lately, which has only one (rather huge) front sub-frame. The Honda of course has two. The very front sub-frame can't be used to adjust camber, it can only affect caster angle.

                Camber can be adjusted by moving the second sub-frame laterally. Moving the second sub-frame longitudinally will also have some affect on caster angle, but it's opposite to what you might expect, i.e. moving the second sub-frame (say) forward won't increase caster, it will decrease it (and vice versa for moving the sub-frame backward).
                Regards from Oz,
                John.

                Comment


                  #23
                  Originally posted by johnl View Post
                  Correction. I've been working too much on the Saab lately, which has only one (rather huge) front sub-frame. The Honda of course has two. The very front sub-frame can't be used to adjust camber, it can only affect caster angle.

                  Camber can be adjusted by moving the second sub-frame laterally. Moving the second sub-frame longitudinally will also have some affect on caster angle, but it's opposite to what you might expect, i.e. moving the second sub-frame (say) forward won't increase caster, it will decrease it (and vice versa for moving the sub-frame backward).
                  Ok, I'm going to try and unbolt and move the front subframe forward.

                  i'm also going to remove the pass side and driver side adjustment shim to increase the caster for both.

                  Is it more important to have symmetrical caster or an increased caster overall?

                  I was thinking I could either add 1 washer to the D/S rod to bring caster to more equivalent angles (1.3L and .9R) or remove both washers and bring up caster for both sides (2.3L and .9R)

                  member's ride thread
                  93' EX Coupe H22A w/ P2T4 Sir 5spd 191whp 155 wtq
                  99' Lexus LS400 157k VVTi V8 gets up & goes...new DD
                  91 Accord SE 176k
                  97' Honda Odyssey 199k miles...$485 spare van for my parents

                  Comment


                    #24
                    How did this end up working out for you? I'm in the same boat as you were as my car pulls to the right despite my front toe being spot on. My passenger front wheel is about -1.5 degrees camber out of spec, and both fronts are off a couple degrees of caster. My driver's side front wheel's camber is off too, but still within range.

                    Originally posted by johnl View Post
                    The Honda of course has two (front subframes). The very front sub-frame can't be used to adjust camber, it can only affect caster angle.

                    Camber can be adjusted by moving the second sub-frame laterally. Moving the second sub-frame longitudinally will also have some affect on caster angle, but it's opposite to what you might expect, i.e. moving the second sub-frame (say) forward won't increase caster, it will decrease it (and vice versa for moving the sub-frame backward).
                    I'd be willing to bet my "second" subframe is off to one side, given how my camber numbers are off.
                    Last edited by wtfisafleek; 08-03-2018, 05:19 PM.
                    My '91 LX build. Bought September 2017. Sold June 2020.
                    http://www.cb7tuner.com/vbb/showthre...r /> t=209871
                    Current mileage: 399450 5/18/2020

                    My '92 LX build. Bought Novemeber 2019. http://www.cb7tuner.com/vbb/showthre...91#post3293791
                    Current mileage: 422679 11/21/19

                    Comment


                      #25
                      I don't think the main subframe (at the rear of the engine compartment) is really meant to be "adjusted". I did have to manhandle the one on the wagon after the curb accident to get it centered under the body. If your camber is high on one side and low on the other, this crossmember might not be centered. What is the camber of the left front wheel?

                      The front subframe is not really intended to be moved to adjust the caster either (not much luck moving it on the wagon to try to correct caster). The shims on the radius rod are intended for adjustment. If you start shortening the large bushings you will affect the stiffness. If you shorten the tube, you will affect the caster.
                      90 LX 4dr 5 spd 396,014 (sold 1/1/2022) - MRT: http://www.cb7tuner.com/vbb/showthread.php?t=201450
                      08 Element LX FWD AT 229,000 - MRT: fleetw00d : 2008 Honda Element LX - CB7Tuner Forums

                      Comment


                        #26
                        Unfortunately I seem to have misplaced the damn paper with all the values, but from what I remember:
                        LF: about +.3 degrees camber, toe was 0.
                        RF: about -1.6 degrees camber, toe was +.01 degrees.

                        The caster for both front wheels was about +1.5 degrees if I remember correctly. I could be wrong and it was just the right front.

                        The real odd thing was they set the toe at +.17 and +.16 for the rear wheels, which I thought was odd. I would think you would shoot for the middle of the range, in this case 0.08.
                        Last edited by wtfisafleek; 08-04-2018, 11:32 AM.
                        My '91 LX build. Bought September 2017. Sold June 2020.
                        http://www.cb7tuner.com/vbb/showthre...r /> t=209871
                        Current mileage: 399450 5/18/2020

                        My '92 LX build. Bought Novemeber 2019. http://www.cb7tuner.com/vbb/showthre...91#post3293791
                        Current mileage: 422679 11/21/19

                        Comment


                          #27
                          The camber is mostly set by the upper and lower control arms. From the factory, there is no adjustment for the position of the upper controls arms. Assuming there is no damage to the mounting point for the lower control arms, you may be able to shift the main cross member to the left to decrease the camber on the left and increase it on the right. Get under the front of the car and assess the position of the cross member vs. features on the structure of the car to see if it looks like it is centered. The pictures below are looking straight up at the outer ends of the cross member - you can see it is shifted to the left (sticks out some from body structure edge, inside it on the right). I was able to loosen the bolts and use a long rod in the hole above the bolt hole to leverage it to the right, then tighten the bolts.


                          Last edited by Fleetw00d; 08-04-2018, 03:50 PM.
                          90 LX 4dr 5 spd 396,014 (sold 1/1/2022) - MRT: http://www.cb7tuner.com/vbb/showthread.php?t=201450
                          08 Element LX FWD AT 229,000 - MRT: fleetw00d : 2008 Honda Element LX - CB7Tuner Forums

                          Comment


                            #28
                            I just got under the car to check and it looks like mine is shifted towards the passenger side ever so slightly. Maybe 5mm? I'm not sure if that would make the difference I'm seeing in my camber measurements.

                            Is it just those two bolts that attach the subrame to the body of the car?
                            My '91 LX build. Bought September 2017. Sold June 2020.
                            http://www.cb7tuner.com/vbb/showthre...r /> t=209871
                            Current mileage: 399450 5/18/2020

                            My '92 LX build. Bought Novemeber 2019. http://www.cb7tuner.com/vbb/showthre...91#post3293791
                            Current mileage: 422679 11/21/19

                            Comment


                              #29
                              Total of four.

                              If the dimension from the top ball joint to the lower ball joint is 18 inches, then one degree of camber would be 8 mm of movement at the lower ball joint.
                              Last edited by Fleetw00d; 08-05-2018, 01:06 AM.
                              90 LX 4dr 5 spd 396,014 (sold 1/1/2022) - MRT: http://www.cb7tuner.com/vbb/showthread.php?t=201450
                              08 Element LX FWD AT 229,000 - MRT: fleetw00d : 2008 Honda Element LX - CB7Tuner Forums

                              Comment


                                #30
                                I think whatever I did last did end up helping. I remember playing with the amount of washers and then put it all back together, took it to the shop and they were able to get the alignment of the car to track straight. I didn't have any problems afterward of it pulling.

                                member's ride thread
                                93' EX Coupe H22A w/ P2T4 Sir 5spd 191whp 155 wtq
                                99' Lexus LS400 157k VVTi V8 gets up & goes...new DD
                                91 Accord SE 176k
                                97' Honda Odyssey 199k miles...$485 spare van for my parents

                                Comment

                                Working...
                                X