A-V8 steering caster

[cuzncletus]

I'm mocking up my 4" drop Model A axle with split A wishbones. It looked to the eye like I had negative camber. When I chucked it all up in a vice, centered the axle, and adjusted the axle so the radius rods were level, using the flats at the top of the spindles and an angle finder, it appears that there's about 10d negative camber in the front spindles.

Questions:

My thought was a Model A axle could be swapped end for end. My steering stops are to the rear with the nuts to the front. Could I have assembled it backwards?

My radius rods are supposed to be Model A's. I had to grind the bottom mounting pad for the radius rods flush with the axle to get the radius rods to fit. Also, the thinner end of the attaching "C" on the end of the radius rod sits forward of the thicker "C" end the spring perch passes through. In other words, with the thin part of the mount on top and the thick on the bottom, the axle has negative camber. Could these rods have been from a different donor? They had been run on a 32 prior to my car but were supposed to have been from an A.

[V8COOPMAN]

You keep referring to the term "camber" throughout your post, but It seems that you're describing ill symptoms that relate to "caster". DD

[Fordors]

The Model A axles have a 2 1/4" thick boss where the spring perch bolt passes through, while the '32-'36 axles will be 2", so it sounds as though your split wishbone is from a '32 or '33-'34. A '32 split w/b will measure around 41 1/2" when cut at the weld for the rear forging and I think a '33-'34 will be about 2 " shorter, although we don't know where yours was cut. The grinding you describe was for the V8 wishbone "C" ends to fit the earlier Model A axle.
As far as your caster goes you have the radius rods upside down. When a wishbone is level the "C" end has a 10° tilt to the rear, so you need to flip the radius rods. All Ford axles have no front or rear, but sometimes there will be a burr raised in the k/p lock hole and it will seem the lock will only go in one way. Traditionally the lock will go in the front and the steering stop will be at the rear.

[Jason in TX]

If you are indeed discussing caster...

Model A wishbones where they connect to the axle are fairly close to zero. With the unsplit bones, the radius rods attached to the bottom of the transmission and traveled up to the front axle, giving it about 6 degrees of caster.

On a 32-34, the front end was lowered to give the car a sleeker look, so you will find that those wishbones openings where the axle connects are canted or tilted back, or up toward the sky. They built in the caster on the 32-36.

If you are splitting Model A bones (already close to zero caster laying flat on the ground) and then mounting the ends to the frame (higher than the bottom of the transmission) you are now tilting the ends down to the ground, and hence your negative caster.

The old trick was to piecut the ends, tip the openings back to the caster you need and weld 'em up, to be more like 32-34 bones.

You can't put 32-34 bones on a Model A axle. The spring perch opening on a Model A wishbone for the Model A axle is 2 1/4". The 32-34 wishbone spring perch opening is 2"


1928-1931 spring perch opening - 2 1/4" and maybe 1-2 degrees caster laying flat on ground




1932-34 spring perch opening - 2" and tilted back more for more caster.



1935-1936 - still 2" opening, but now have spring hanger built in.



1937-1941 - opening enlarged back to 2 1/4" (would fit model A axle) They also have the spring hangers built in, but this one has been cut off.




IMG SOURCE - Hot Rod Confidential Forum

[cuzncletus]

OK. I caster'ated my camber, or vice versa. It is indeed caster. Jason in Texas; thanks for the photos. Mystery solved. The bones are 37-41's. Someone did a nice job of cutting and grinding the spring hanger off, then rounding it to match the contour of the mount. Will these work OK on my A-V8? This also eliminates some of the radical drop I was having to look at doing to the tie rod arms.

[JSeery]

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As others have suggested, determine where you want to mount your radius rods and then adjust your castor with "pie" cuts to the radius rods. It is best to wait to adjust the castor until you have the ride height of the frame figured out with the frame sitting on all four wheels and all the body, engine, transmission, ect. weight on the frame.

[Krylon32]

Some caster can be set by the length of your rear wishbone mounts. I try to set the caster with bones or hairpins at 5-7 degrees at ride height. I also try to put about 8 degrees caster in the front cross member. I find most quality dropped axles either new or an axle dropped by a competent shop to have the correct camber. I also like my toe in at an 1/8 for radials and 3/16 for bias belted tires. I put this information on the front crossmember of all my customer chassis.

[pooch]

What is the exact size diameter of a perch bolt and the exact size hole in axle ?

[Ralph Moore]

37-41 bones will work just fine for an AV8. I have them on mine. Welded seam to the top mines set at 6.6 degrees caster.
Model a crossmember in a 32 frame. I canted it back a few degrees before welding it in.