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Just had an old pro attempt an alignment on my 61. I installed passenger hubs so the spindles are 1 inch lower. I put two castor shims in so that i could get some additional castor but when i was attempting to adjust castor i could only get approx 2 degree on the driver side and -.4 on the passenger side. The old pro attempted on get additional castor but could not. He tells me the frame is good but he believes the hubs(spindles) are bent which is causing the problem. Does anyone know how to check for bend in the hubs (spindle). I'm trying to get to 4 degrees castor and i'm a long way off. I read a thread from last fall with a great discusion and ideas but I thought I had better check for what the pro suggested before getting further into this.
This is the as found and as left information on my 61.
I can't make out on the printout, but doing a caster cut during the alignment will give you a readout of SAI (Steering Axis Inclination). It used to be called KAI (Kingpin Axis Inclination). Either way, if the SAI is different from side to side, it is indicative of a bent part, usually a steering arm (knuckle/spindle). Visual inspection up close is needed, with comparison to a 'known good part'. You may have one side that took a hit, or both, over the past 60 years. Your alignment guy sounds like he knows what he's doing. As an alignment guy myself since the early '80's, I can tell you it is very hard to see a bent steering arm.
From personal experience with disc brakes a bent spindle is fairly easy to find by trying to install new, full thickness brake pads - they won't go. On a drum brake car it would be a lot more difficult. You could probably drill a large flat piece of steel plate and bolt it in place of the backing plate. Then install the drum and measure the distance of the edge of the drum to the steel plate all around the circumference. If it's bent very much you may be able to tell just by the relationship of the drum edge to the backing plate or lopsided wear on the brake shoes.
Dropping the front an inch like that has nothing to do with the spindles being bent.
It is possible the spindle supports (which is what you changed) are bent, but probably not.
Dropping the front changes the caster quite a bit, you will need to put second set of 2* shims between the front cross member and frame.
If you are going to do that, order two sets of shims because the originals are probably badly corroded if they have never been changed.
Edit: i read your post a little better and see you aready have two shims per side, assuming they are installed correctly (thin end to the front of car on all shims, you may have a tweaked frame.
I wasn't that hard to bend the frame just behind the cross member in an accident.
I can't make out on the printout, but doing a caster cut during the alignment will give you a readout of SAI (Steering Axis Inclination). It used to be called KAI (Kingpin Axis Inclination). Either way, if the SAI is different from side to side, it is indicative of a bent part, usually a steering arm (knuckle/spindle).
I'm not an alignment guy but this sounds right from some of my past reading.
Seems like this is the method to check..........
How is kingpin inclination measured?
King pin is located inside and at- tached to the axle of a car. Since king pin is not directly accessible, its angle cannot be measured directly. To measure these angles, the steering tires mounted on the vehicle are turned 30 degree left and 30 degree right about the vertical axis and its tilt is measured.
Alignment guy say frame is OK. Not sure how he knows but he is the pro.
I wonder if I could put the spindle portion in my lathe and measure runout against the hub?
I can't image anyway they could be bent enough to cause a caster issue. Camber issue, yes, caster, no.
The spindle supports, yes they could be bent to cause caster problem.
Now, what was your caster reading before you installed the new spindle supports?
You can bring the offending side in closer by grinding the inside rear of the outer slot on the top control arms to allow the top of the spindle support to go a bit more rearward.
You can certainly try to put the spindles in the lathe and see if visually, the outside flange mating surface the backing plate mounts so, has any run out, the spindle kingpin mount portion, is very eccentric to the spindle.
Jerry, I don't see an SAI measurement on your printout. We always have them on ours (Hunter Equipment). Can your guy give you the SAI reading? He must have had it to make the bent part call. When a steering arm is bent, it's almost never the spindle itself....it's the knuckle arms or attaching points. SAI is a non adjustable, permanent angle, so it has to be the same side to side for everything to work as it should.
I wonder if i should take some "corrective" grinding and mounting shims on the A arm and adjust the problem out rather than chase the bent spindle/hub idea. Would that approach cause other problems like in the brake shoes?
You can't 'adjust out' an SAI problem because it is a non adjustable angle that goes though and arc as the wheels are turned. You'll just go further down the hole by grinding things. My advice, if you can't locate the bent part, would be to purchase a new front end assembly and bolt it in. There are so many resto-mods being built these days that old C1 frames and front ends seem to be pretty common, and not too pricey. Get a different front end, freshen it up, bolt it in, and you should be good to get it aligned and on the road.
Tell me why the kingpin inclination angle can't be changed, when the spindle support, the holds the kingpin top and bottom, can be moved in/out, front/back. You are changing the KIA relative to the ground/frame by moving the top of the spindle support around.
I brought my caster/camber into spec by grinding the rear slot of the top control arm to allow another 3/4 turn on the upper outer adjustment shaft.
Doug
Tell me why the kingpin inclination angle can't be changed, when the spindle support, the holds the kingpin top and bottom, can be moved in/out, front/back. You are changing the KIA relative to the ground/frame by moving the top of the spindle support around.
I brought my caster/camber into spec by grinding the rear slot of the top control arm to allow another 3/4 turn on the upper outer adjustment shaft.
Doug
The SAI angle is the measurement of degrees through the lower ball joint (kingpin) to the upper BJ or kingpin and the tire at a vertical position. SAI does not include camber. It is designed into the suspension, and causes the spindle to dip slightly downward as the wheels are turned in an arc. It helps with steering wheel return and stability of the vehicle. Changing the position of spindle support will alter the camber, but won't fix SAI, which only changes due to a bent component. You can google SAI and get all the info you need. You brought your camber/caster into spec, but you didn't fix your SAI if you do have a bent part (difference in angle from side to side is a bent part). That's simply the way it is.
But the king pin support upper outer shaft also adjusts camber, on a C1. What is the diff between a bend in the support,and moving the top of the support in, or out at the top? I don't see any diff, unless the bend, is greater than the upper king pin support adjustment limit.
Doug
You're right Doug I don't have that. I did a complete frame off after I purchased car so I never took any alignment numbers before I rebuilt the front suspension. Sorry
Fixing/replacing the bent part is the way to return the car to manufacturer's specs and make it handle and steer as it should under all conditions. What you guys grind and shift and move is up to you. Not my car. Have fun.
I'm an old Mechanical engineer. I plan to check the spindles and hub for any bent components and if any are found ,depending the the degree, either replace or repair. I have to confess that I like Dougs approach on this. The tire and suspension doesn't "know" if corrective action was taken at a mount point to put this factory geometry back in the suspension. More to follow.
Doug can you post a photo of your modification? Jerry
Bent hubs(spindle)
