Duke - Squirrelly steering

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  • Timothy B.
    Very Frequent User
    • January 1, 2004
    • 438

    #1

    Duke - Squirrelly steering

    Duke and others: I took an extended drive today in my C2 as it was in the 60's here in Houston and beautiful clear skies. As you recall from other posts, I have the Pirelli P4000s and recently had my car aligned (specs below from an earlier post). The car drives nice and I like the tires, but I do feel what I would describe as "squirrelly" steering about the center position while driving any speed from about 30mph up. The car doesn't wander or pull, but it is an uncomfortable feeling that is hard to describe. I only get this feeling when driving a decent speeds when making small steering inputs to stay on the road. It feels fine when actually turning at intersections. Corning forces seem good and I havne't noticed my rear end wanting to come out when aggressively taking corners. I know I'm probably not describing this well, but I was hoping that from my specs you might be able to point to something that would produce this feeling. Remember that I was actually targeting more positive caster but couldn't get it as we ran out of adjustment range on the right front. I plan to go back to the alignment shop again now that I have the new Pirellis, and can request a specific change in settings if you have a suggestion.

    Here were my alignment results from about a month ago or so:

    Front camber left: -0.85 deg right: -0.52 deg
    Front caster left: +1.24 deg right: +1.88 deg
    Front toein left: 0.16 deg right: 0.16 deg
    Total toe front: 0.32 deg

    Rear camber left: -1.07 deg right: -1.04 deg
    Rear toein left: 0.05 deg right: 0.06 deg
    Total toe rear: 0.11 deg
    Thrust angle: -0.01 deg
  • Terry F.
    Expired
    • October 1, 1992
    • 2061

    #2
    Re: Duke - Squirrelly steering

    Truly, I shouldn't be commenting. I have just recently started to read about aligning a corvette. Based on what I have read so far...for street driving using radial tires I would shot for 0 degrees camber front and back. But, that may not be the problem. If I was doing the alignment myself I would look for worn front end parts (idler arm and tie rods). If that stuff is all new, then forget them. But, if they are worn or any of the other front end parts are worn out, you may have a condition where at higher speeds you are effectively loosing your toe-in. At higher speeds any looseness in the steering system will want to pull the front wheels back and apart. Hey, but what do I know? I am only guessing. I am sure Duke and others would have better ideas.

    Regards, Terry

    Comment

    • Terry F.
      Expired
      • October 1, 1992
      • 2061

      #3
      Re: Duke - Squirrelly steering

      I forgot to say, since your rear seems to be tracking and handling fine I would say that it sounds like you need more toe-in on the front. I would try to measure it yourself and see what you get. But, it is probably possible for the back end to push the car around if not aligned correctly also. I guess I would try to measure the toe-in on both. Let me know what you find. Terry

      Comment

      • Terry F.
        Expired
        • October 1, 1992
        • 2061

        #4
        Re: Duke - Squirrelly steering

        Sorry, I keep thinking of things. What is the condition of the steering box? Is the car manual or power steering? Terry

        Comment

        • Justin N.
          Expired
          • February 1, 2004
          • 0

          #5
          Re: Duke - Squirrelly steering

          Tim,

          I'm the furthest from an alignment specialist, but my old roommate's 66 sb conv. Corvette has power steering and it wanders around quite a bit. It has a rebuilt steering box, newer front bushings, and BFG Radial tires 215/?/15 on factory 67 Rally wheels. I personally don't like power steering and I'm quite glad my 67 coupe doesn't have it!

          Justin #41362

          Comment

          • Patrick H.
            Beyond Control Poster
            • December 1, 1989
            • 11372

            #6
            Re: Duke - Squirrelly steering

            3 things I think of...

            1. Worn and/or out-of-adjustment steeing box. After this many years you box is likely out of grease, as well as out of adjustment. Consider sending it to Corvette Steering Service for a rebuild. www.corvettesteering.com
            No affiliation, just a satisfied customer.

            2. Worn tie rod ends.

            3. Front wheel bearings are too loose.

            I've experienced all 3 of these in at least one of my cars. I'd check all 3 before moving on. I doubt it's your alignment.

            Patrick
            Vice-Chairman (West), Michigan Chapter NCRS
            71 "deer modified" coupe
            72 5-Star Bowtie / Duntov coupe. https://www.flickr.com/photos/124695...57649252735124
            2008 coupe
            Available stickers: Engine suffix code, exhaust tips & mufflers, shocks, AIR diverter valve broadcast code.

            Comment

            • Duke W.
              Beyond Control Poster
              • January 1, 1993
              • 15229

              #7
              Re: Duke - Squirrelly steering

              I need something more descriptive!

              Corvettes (especially with manual steering) should have a fairly strong on-center feel, and a noticeable effort should be required to turn the wheel off center, and the steering wheel should show noticeable returnability if you turn it off center and release the wheel.

              A lack on on-center feel with little effort to turn the wheel off-center and a lack of strong returnability can be disconcerting. Is this what you are experiencing?

              I also need to know if your car is manual or P/S.

              I also recommend hard urethane link bushings in the front anti-roll bar to control arem links. What is installed? The OE type rubber pillow block bushings are okay.

              I would like to see less front crooss caster and corss camber. (The rear looks just about perfect!) See if you can get the left hand caster and camber closer to the right.

              Also a thorough inspection for excess wear an any suspension and steering parts is in order.

              I'd also like to know the shim stack thickness at all four postions on the upper control arm mounts.

              Duke

              Comment

              • Gerard F.
                Extremely Frequent Poster
                • July 1, 2004
                • 3803

                #8
                Re: Duke - Squirrelly steering

                Tim,

                When I put on power steering, it was recommended that I go to 21/2 deg + positive caster on both fronts. If yours is an add-on power steering, make sure they put the steering rods in the forward holes (closer ratio) in the wheel spindles.

                Mine was squirrelly at high speed until I made these changes on my 67.
                I'm running 2.75 Positve caster with coker radials, and it centers fairly well with a little feel now.

                Jerry Fuccillo
                #42179
                Jerry Fuccillo
                1967 327/300 Convertible since 1968

                Comment

                • Timothy B.
                  Very Frequent User
                  • January 1, 2004
                  • 438

                  #9
                  Re: Duke - Squirrelly steering

                  Thanks for the responses! Here is some more info. I plan on driving the car a bit again today and will try to get some more information.

                  My car has power steering and links are in the required quick ratio holes. All front end bushings are new. Actually, the entire front and rear ends have now been rebuilt except for the rear differential. I must tell you however (and I suspect some of you will rattle my cage about it too), that my front bushings are poly, as are the rear trailing arm bushings. Front sway bar bushings are also poly.

                  Steering gear was rebuilt by me last year, and steering is nice and tight really. I just had the column apart and replace bearings to correct the last bit of slop in steering. Idler arm is newish also (very tight actually).

                  I have a feeling that I might be experiencing a lack of toe in as it does feel similar to that. As Duke says it might also be a lack of on center feel. I will look today and report the shim thickness, but I do know as I mentioned in an earlier post that I have lots of stack on the rear of both sides (more on the right however) and maybe one or two shims on the front. The alignment guy said he couldn't get any more positive caster on the right front, and was recommending that I get a "kit" that has an offset upper arm to compensate. He say he sees lots of Vettes with this problem.

                  Overall my car drives great, much better than it used to before all the work I have done on it. It is only the on center feel really that remains for me to think about. I will let you know if I can discern any more today during my drive.

                  Comment

                  • Timothy B.
                    Very Frequent User
                    • January 1, 2004
                    • 438

                    #10
                    Re: Duke - Squirrelly steering

                    Also, I should mention that I have GT front coil springs (460 lbs/inch) installed. Standard rear 9 leaf steel spring but it is newish.

                    Comment

                    • Gerard F.
                      Extremely Frequent Poster
                      • July 1, 2004
                      • 3803

                      #11
                      Re: Duke - Squirrelly steering

                      Tim,

                      I've got the same springs in my 67 conv with gas shocks, original front stabilizer, no rear, new nine leaf rear spring. I went to all polyurethane bushings front and rear.

                      Jerry Fuccillo
                      #42179
                      Jerry Fuccillo
                      1967 327/300 Convertible since 1968

                      Comment

                      • Mark #28455

                        #12
                        positive vs negative caster

                        Caster is the angle of the axis connecting the upper and lower ball joints vs. a vertical line. Positive caster means the upper end of the line is leaning toward the back of the car. If the large stack of shims is on the rear bolt for the upper a-arm and the smaller stack is on the front bolt, you are tipping the axis forward, not rearward. I don't understand why your mechanic would say you have the "most" positive caster possible as this would occur with the larger stack of shims on the front bolt.

                        If the caster goes negative (axis tipped forward instead of rearward) you will have a car that doesn't want to center the steering and would be very squirrely.

                        Please verify that you really have positive and not negative casteron your car.

                        Good luck,
                        Mark

                        Comment

                        • John H.
                          Beyond Control Poster
                          • December 1, 1997
                          • 16513

                          #13
                          Re: positive vs negative caster

                          Mark -

                          The upper control arm shaft is located INBOARD of the frame bracket, so you add shims to the rear bolt to move the upper ball joint rearward, increasing positive caster. If the shaft was located outboard of the frame, you'd remove shims to achieve the same result.

                          Comment

                          • Duke W.
                            Beyond Control Poster
                            • January 1, 1993
                            • 15229

                            #14
                            Agree with John! *NM*

                            Comment

                            • Mark #28455

                              #15
                              you're absolutely right, I got it backwards *NM*

                              Comment

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