I know this has been discussed many times and I've read some of the old threads. I see two approaches presented. One says to put the big wrench on the axle and use it to bend the wishbone. The other other says to remove the wishbone and heat the ends and bend them. Will either work with equal success? I am wondering if the heat approach isn't better in that it ensures the bending happens at the end of the wishbone and not somewhere along its length.
A couple of us here are studying our front axle alignment with a bit more scrutiny and want to get it right in the safest and best manner.
no. the later, bolts UNDER the axle.
The spring perches and wishbone(angle and length) both determine caster. It takes some careful inspecting and measuring of the front end before changes are made.
I think that to change caster, one needs to put a twist on the axle ends. Bending the wishbone might shorten it a touch and reduce the caster There is no easy way to make it longer to increase the caster. I am not sure bending the wishbone is a good plan as it will make it less rigid. More than likely you are trying to increase the caster anyway.
It probably depends on how much it needs to be changed. Mine was way off and I heated the ends of the wishbone and bent to were they needed to be. Worked great and car runs straight down the road.
If just a little change is needed I bet you could dress the surface of the wishbone were it contacts the axle.
Also note that there is an error in the service manual. I would go with 3/8 to 1/2" offset to be near the originally recommended 5 1/2 degree caster.
Unless you have the spring perches swapped over from right to left, or the wishbone is bent, or the axle is bent, there should be no adjustment needed. I would check each of those 3 areas to determine what the problem is and correct the root cause accordingly.
One thing I think that is sometimes over looked is the wear in the ball socket at the oil pan. If you look at them, they always wear up into the pan thereby decreasing the caster. Most people add shims in the cap instead of repairing the socket. A little wear in the socket becomes a good bit of movement at the axle. Think about it, something to check. KB
a "little" wear in the socket means even "littler" movement at the axle. If the distance from the axle to the wishbone is 24 inches, (I'm just guessing since I don't have one handy), and the kingpin height is 6", (again, guessing), then 1/8" wear in the socket will only cause 0.3 degrees reduction in caster angle.
(That 1/8" is assumed to be additional socket depth, due to wear, which will cause the wishbone ball to sit higher, thereby rotating the axle forward.)
Keith makes a good point. Its a rather long moment arm at work. I'll check and see where I put the shim on mine.
Thanks for the input from everyone.
Jerry, the wear is actually up and back which tilts the axle rearward at the bottom, think about it. KB
Take a good quality hand tool which would be made from vanadium steel, try and bend it! then heat it up, bend and let it cool, try and bend it again.
It would have reverted back to a milder steel, do you really want to do that to a front end of a T?
A hardened and tempered modern tool is much different then a Model T front end. The Model t front end is pretty much made out of mild dead soft steel. Heating will not change that. Many folks have heated the axle to remove spring perched with no ill effects ever reported. Also some heat and bend axles like a pretzel to make drop axles for speedsters and again no problems.
We had a thread once before on what the front axle was made of, if I remember rightly, records and Ford publications did show it was vanadium steel.
If the socket in the crankcase is worn considerably, as many of them are, the best way to fix that is to replace the socket with a new one, of course. But if you're looking for a quicker and easier way, you can get a repro cap for that area made of brass. A little "surgery" on that part, and it can be put in upside-down, taking up quite a bit of slack and increasing the caster. Just do a bit of grinding on the outer face so it snuggles into the enlarged socket. I'll probably get chastised for suggesting this quick fix, but it's been done lots of times for lots of years with good results.