Hot Rods Dumb Model A Question Part 2

I want to thank everyone for their "Axle" input, especially Lostone and Alchemy. . Thanks to your perseverance I think I've got a pretty good understanding of caster, how to measure it and how to get it right with the car.

When I figured out that due to the header I need to go to a split wishbone, before taking the axle back off for measurements [and maybe adjusting, if I get brave enough] I figured I'd better mock up some of the other parts just to make sure everything fits.

So, I'm going back to the build thread for more embarr***ingly dumb questions so stay tuned.
That's here;
https://www.jalopyjournal.com/forum...anical-brakes-etc-build-thread.1341093/page-5

And, once back to the axle issue, I'll probably be back here.

Thanks again,
robj

 

I'm not sure why I've been avoiding this somewhat, maybe it's just nice to look at the axle installed and feel like progress is being made. I have been doing other things, bell housing work, pedal bushings, prepping the 12" front brakes [and rebuilding the engine of a "free" Kawasaki Mule my son got.]

I saw someone else that had the "Reds" header installed and he reports very limited clearance between the header and the wishbone when at rest. Like less than 1" which to me isn't enough. He hasn't driven his yet but I suspect there will be issues.
With this in mind I bought a "Geardrive" header, [also sold by Millworks] They specifically say it will fit the stock wishbone. I do have to say the overall fit and finish of the "Reds" header is much nicer.

So, splitting the wishbones is off the table which is probably a good thing.
Anyway the front axle is coming off this week and using your suggestions I will report what I find.
Please hang around as I'm sure there will be questions.
thanks, robj

 

Okay, I finally bit the bullet and removed the axle and put it in my vise. Made some plates to hold it better.



In addition, I may be getting a little less stupid. Maybe...

I'm in the "Model A Restorers Club, [soon to be excommunicated I'm sure] but there was a post where a guy asked if there was a front and rear to a Model A axle and the answer was no. It started me thinking, so I asked if a Model A axle had any pre-set caster and the answer was again, "no".
So all of the caster is set by the position of the wishbone it seems. Is this correct?

No wonder I was so confused. It sure would have saved me killing off sooo many brain cells if I had figured this out sooner.
So the factory setting of caster is 5 degrees, but I've seen references to settings of 7-9 degrees. Is that to improve straight line steering? But again, this is all done with the wishbone?

Note; Mine are at 2.5 degrees positive caster on one side and 3 degrees negative caster on the other side. With 0 degrees on either side of the vice and 1/2 degree in the middle between the vice and the kingpin on both sides..

Also, the only setting that's pre-set from the "factory" is camber, set at 1-2 degrees of positive camber.
Would that same adjustment hold true for say a 600.16 radial as opposed to the original 6:75 5:00 x 19 size tire? Or would a different setting work better with the 600x16?
Of course, mine are measuring 11 degrees and 9 degrees negative camber. Is there any reason these would be different on a dropped axle?

Before I go any further, is any of this correct?
Thanks,
robj

 

If I am understanding this correctly, - sounds like it is bent, possibly hit in a collision ?

 

I have always been told 7 degrees, where others say 5 - 7 degrees.
My sedan has 10 degrees, but from someone else’s recent experience, where he changed from 10 degrees to 5 degrees with much benefit, I am rethinking the 5 - 7 degree range……
Yes, done with the wishbone and caster amount corresponds to the top of crossmember or bracket that holds spring as described in posts 5 and 6

 

Rob, if your axle has caster that is over five degrees different from side to side, just sitting loose in the vise, then it is seriously messed up. No good at all.

Yes the axle has no front and back. Yes the wishbone holds it where it needs to be for caster. Yes lots of hot rodders like seven degrees for their final caster.

But remember that you can’t measure actual final caster until the car is all done, with real tires, and sitting on flat ground. That’s what makes the whole ordeal so hard with old Fords with wishbones. The only adjustment requires cut and weld.

 

Or, it was dropped incorrectly. And maybe not a great axle to begin with.

 

I'm not sure what to do with it at this point. I'm going to reach out to Sid and describe what I have going on and see what he thinks.
I bought the axle from "the guy" who dropped it but I still have my original axle. I'm going to put that in the vice and check it tonight. Depending on what Sid says I could get that one dropped by him.

I'm not sure if the axle had issues to begin with or if it was dropped poorly. It was done by a well known guy that isn't Sid.

I'm slowly working my way towards a mock up with the engine/trans/radiator/body, all the heavy stuff temporally installed and sitting on the wheels and tires I'm going to use.
I guess the good news is I finally figured out what I didn't have figured out...
Thanks,
robj

 

Part of this discussion, [caster/camber] is also taking place on the Model A Restorers Club FB page where I had posted a question. One of the members said neither castor or camber is adjustable, [referring to a stock Model A] and another member said they were, [back in the day] with original Ford dealer tools. He posted some shop manual photos of the tools which I had never seen or even heard of.
It appears they were adjusted cold. Pretty interesting.

 

even using a hairpin, (or any adjustable set up), one needs to get as accurate as possible to begin with.
If you are way off after adjustments, your spring will bind more, with quicker wear on components and will give you compromised ride.
When I built my ch***is originally, the one error I made was not adjusting the cross member to match the caster, - the binding was obvious just looking at it !

 

My axle was bent when I got it. Took it somewhere, (I forget where, but probably just the local engineering workshop), and they straightened the castor in a press and tweaked the camber with chains and hydraulic jacks, same principle as in your photos, also done cold.
- if you can drop them by heating them, could they be adjusted by using heat also ? I don’t see why not.
Mine drove beautifully, even with the cross member set incorrectly at the time, but have since changed the axle for aesthetic reasons.

 

good to see it’s not only on the HAMB where we disagree with each other……..………

 

I’d bet the old straightening info is to fix accidental bends, not to make changes to stock alignment.

 

So I made the decision to attempt to make the drop axle I have work. Like Dad always said, if it already broke, it's hard to make it "broker". And if worse comes to worse I can get my original axle dropped and use the failure for wall art or a lamp or something.
Right now the axle is clamped in a vise as level back and forth and fore and aft as I can get it. I used a piece of steel referencing the perch mounts. I figured that's as a reliable starting point as any.



I also turned some pipe on the lathe to fit pretty snugly in the perch mount holes and the kingpin holes. I was thinking the longer length would magnify imperfections, but now that I really think about it probably doesn't make much difference. It might make imperfections easier to see though.



Checking the spring perches first, fore and aft, both are at 90 degrees. [Finally, something], but side to side, one [p*** side] is at 81 degrees, while the drivers side is at 83 degrees.
Pretty close and I'm not sure how critical that is and it very well could change after the rest of the axle tweaking, but I wanted to have a reference. I guess it could generate bind with the spring or at the very least some twist. How much deviation is too much? Is 2 degrees too much? [after thinking about it, as I will probably have to pie cut the wishbones, I can account for any discrepancy there at that time]

So a question. The factory setting for camber is 1-2 degrees positive. Is there any reason to deviate from that when going from the original 6:75 500 x 19 original tire to a 600 x16 radial? [the new Coker Excelsior Radial]
I think I read somewhere that the positive camber makes steering easier, but 0 degrees or 1-2 degrees negative camber makes handling a little better.
My axle is currently measuring 10.5 degrees neg. camber on the p***. side and 7.5 on the drivers side. My thinking is this would get adjusted after [or at the same time] as the caster adjustment.

At this point I'm still pondering how to secure the axle for heating and adjusting. My feeling is any of this adjustment should take place outboard of the spring perch mount so I was thinking about using a large diameter bolt, turned to fit the spring perch and bolting that down to a thick plate with some shims for the correct angle for the bottom of the perch mount.

Note; I have been previously accused by my garage buddies of over-thinking things...

Any suggestions are appreciated.
robj

 

The spindle has angle in it, so make sure you add that in when you adjust the inclination of the king pin.

 

O.K. been away for awhile and playing catch-up !!

A couple things, that's way too much deviation from side to side. I'd be looking along the lines of 1/2° max deviation from side to side.

2-total caster at this point means nothing with it in the vise, 2° positive, 8° negative doesn't mean anything. All that matters is side to side deviation. Total caster is set by the wish bones, hairpin etc ONCE it's mounted in the car.

3- it's forged steel so bending it, straightening it isn't a problem so I'd see what I'd have to do to straighten it first.

4- I've used all of that old tooling to do exactly what was shown above. I've bent caster, I've bent camber it everything from model A's to semi trucks. 100's of times. Again forged steel, if Henry Ford can twist one in a pretzel to show the metal quality then I can twist one for caster and camber and not hurt a thing.

Now with all that said it must be done cold, we want it to bend not stretch, start putting a lot of heat in it and your stretching the metal not bending it.

So I hope all that makes since and helps you out !!

 

After considerable pondering [and consternation] I made the decision to send my original axle to Nostalgia Sid's. Talked with him a few times and although he was willing to straighten out the dropped axle, to drop my original wasn't that much more money.
And my original axle is in decent shape measurement-wise and much, much better condition cosmetically.
I did go a little overboard on the shipping though. I made a plywood box the will accommodate both the original axle and the axle when it's dropped.
And if anyone hasn't tried "Pirate Shipping" they were half of the normal UPS rate and you drop it off at UPS and it's shipped by UPS.

This is the kind of thing that takes place when retired..
Now back to the original build thread here;
https://www.jalopyjournal.com/forum...etc-build-thread.1341093/page-6#post-15886991

A big thank you to everyone for their help!
robj