We are working on a 40 ford coupe that has an unusual problem. The car is set up with a dropped I beam, split bones on a chassis eng. kit, a panhard bar mounted to the driver's side of the frame, and the pass side of the axle. The steering box is a GM 605 power box. The geometry of the steering is correct, the box is centered, the tie rod ends are fresh, wheel bearings are fresh and set, recently the kingpins have developed minimal slop. The problem has been with the car since the owner bought it years ago. When on a sweeping right turn the steering "pulsates". From inside the car you can see the nose of the car shift tithe left, then back to the right, feeling like the car is not going to hold it's line. There is not much feedback through the wheel, and if you hold the wheel steady, the car will mostly follow your line through the corner. Also the outer third of the front tires are scalloped. We have some ideas where to go next, but we are looking to see if anybody has had this problem before.
Can you post a picture or two of your front suspension? It'll be worth a thousand words....to help us diagnose the issue.
sounds like it might be in the steering box itself.... if you are not feeling it thru the steering wheel..... post a picture or two of the setup......
How are the steering arms on the spindles set up? Modified stockers, or bolt on replacements? I'm thinking if modified stockers, Ackerman is not correct on the passenger side only, leading to right wheel running a different track through the turn. This slip angle, coupled with a slightly loose king pin would do exactly what you are talking about. Now that I think about it, could be either side.
sorry, I posted it from an IPhone, and it auto corrected... Panhard, not panagaea Chip, you are on the track of my first thoughts, they are aftermarket dropped steering arms, and it did it before, and after new kingpins, which have now worked themselves loose. one thing we are thinking is that it could be possible that the panhard bar is flexing in the right turn, as it is compressed by the power steering. We are deciding between trying a 525 box, and reinforcing the panhard bar.
Thankyou...I find it quite hilarious that an Iphone autocorrected a term having to do with ancient geography, than a term that probably has more use since about 1940 or so...just shows to go ya that not all electronic gadgets are up on latest terminology... R-
Front end might be all perfect, could be induced by something from the rear suspension; intermittent compliance under/oversteer.
Hey Greg, two more thoughts. Shackles hanging at about forty-five degrees? I know with a panhard bar its not supposed to matter, but I have seen simalar circumstances where it did make a difference before. How about a rear panhard? What side is it swung from? I know you well enough to know that you checked all this, but maybe?
Hey Greg: Has that steering box been the same one all the time the problem has been there. A little off the wall but being a P/s box maybe the control valve has some kind of issue in one direction with pressure control, internal leakage.
Also check to be sure that the U-bolts are tight and that the center bolt of the spring (the bolt that holds the leaves together in the center and also locates the spring in the crossmember) is correctly seated in the center hole of the crossmember and has not sheared off allowing the front end to shift to one side.
I would experiment with more/less toe in. After that, I would look closely at the rear behavior. Is the suspension loading and unloading in the turn?
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