He took the dead perch out, so without that it has to have a Panhard bar. Or, put the dead perch back in, one or the other.
Can you explain Dead Perch? I think I know what it is. Also roll the car forward at least one or two tire rotations before you check toe-in, it makes it " as driven " removing all slop in all joints.
Ok, just the facts! To quote Jack Webb! If you have a straight axle and get the wobble, the very first thing you need to do, is check for worn suspension components. With worn suspension components,alignment means nothing! Once you insure all your suspension components are in good shape, set your alignment to specs! This needs to be done anyway! If you still have the problem, check to make sure your wheels and tires are round, in line and balanced! If you still have the wobble after all this and everything appears to be perfect, take out, or put in a few degrees caster toward the edge of specs or even a degree or two out of specs. This will stop the wobble! Trying to fine the cause of the wobble, can be impossible! Believe me it can hide! But the above procedure will stop the wobble! After you stop the wobble, then add the dampner for insurance! Never put one on to stop the problem, fix the problem first! Bones
That's unusual. It is not often that scrub radius is described using a diagram showing positive camber...
So crosssteer needs a pan hard rod? Early Fords didn’t use them, I think maybe until ‘39 or so. Were the earlier ones subject to wobble?
You are correct, the early Fords did not have a Panhard bar, but they are improved by adding one. Excellent thread: https://www.jalopyjournal.com/forum/threads/this-brouhaha-about-roll-centres.629334/ And hey, @Hildy56 , What happened with the pics...???
There’s not too many images that I could find so I cut out a portion of the original image because there wasn’t many, make if any illustrations showing a solid axel. Just concern one’s self with king pin center line in relation to center line of the tire where it meets the pavement.
I’d say Ford introduced panhard rods when they changed the spring design from preloaded to non preloaded? Or just when they went from side steer to cross steer in 1935?
Bought a wrecked jeep (sheet metal) and installed a 4" lift kit along with 12" wide wheels and tires. Couldn't get over 20 mph without a horrible death wobble. Took it into the alignment shop and he couldn't find anything wrong. All the tie rods ends were tight and steering dampener was good. Good alignment. I replaced every tie rod end and a new steering dampener. I couldn't find a problem with the old parts. Put rig back on the ground and took off down the road, hit 20 mph and no more death wobble. Up to 60 mph, no problem. I can drive up to 70 plus mph without any problem.
I don’t know. I had a ‘39 rear, clutch brake pedals in a ‘36 PU. Also in the bed was the front bar as well, so I’d just assumed it all came from the same vehicle, hence why I mentioned ‘39. But I’m no expert at all.
This is why I asked if toe “out” would get worse if one were to roll the axel back for more caster. Op has said he never checked his toe.
My 39 never had a panhard bar. Front or rear. I thought they came along in 41, but I'm no expert either. lol
lol. Like I mentioned, the PU I had was with ‘39 parts and the bar was in the bed. So I did the ASSUME thing, obviously I was the ASS.
Early Fords had Triangle Shaped ["A" shaped] bones., not split bones And also the correct shackle angle As soon as the wheel gets "re-invented" by splitting the bones, and reverse eye the crossleaf [so the eyes are on the outer side of the arch] the problems start. Scrub radius is a factor of king pin inclination not camber. Smaller rolling radius increases scrub radius unless positive offset wheels are used to counteract this A dead-perch is a classic example of "Silver wiener syndrome" [If a winning racer glues a silver wiener to his car, all the Hot Rodders and Street Racers would do the same.] The dead perch was an early Sprintcar and Midget technique where they're are constantly fighting a losing battle with weight. The Cross leaf doubled as a panhard bar, and used in conjunction with cowl steer so it didn't cause bump steer.. On left turning cars the dead perch was always mounted on the L/H side to keep the leaf under lateral tension. This also cause the L/F wheel to "grab air" which didn't matter. R/H dead perches would result in an undesirable jacking effect on L/H corners. A dead perch is not overly desirable with cross steer, because it is almost impossible to engineer out mechanical. bump steer. The axle will arc basically 1/2 the spring width. whereas the drag link is much longer. If somebody insists on a dead perch, the perch must be on the opposite side of the steering box [passenger side] A L/H dead perch with a L/H steering box causes the axle and steering to arc in opposite directions. A panhard bar is far superior with a cross steer because it can mimic the arc of the drag link.. Any driver who is capable of driving at the limit of tyre adhesion would certainly notice the flaws in a dead perch / cross steer combination.
Which always begs the question "is that sitting in the driver seat or facing the front of the engine"? Now that I think about it....is it LHD (normal) or RHD (across the big water). What say you @Kerrynzl
Across the big water, steering on the Right side .... is the right side But in the USA steering on the Left side .... is the right side But to add to the confusion Driving on the left side .... is the right side But in the USA driving on the right side .... is the right side It is a simple concept to overcome, Just get a single seat open wheeler and apex the corners [road rules don't matter]
Was always taught that L/H vs R/H was determined with your butt parked in the driver's seat. Told my students that when dealing with customers, use drivers side or passenger side because most customers were smart enough to not screw that up.
Try an Adjustable spring perch after your measurements are correct and it still occurs. I believe they allowed my spring to travel in more up and down path than a fixed perch.
Left or right doesn't matter where the driver sits. It's left or right as the car faces forward, same as a person.
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