Technical I've Got To Be Missing Something....Caster & Wishbones

Mocking up the suspension on the B4Cdan, I can tell something is out of kilter, but can't put my finger on it.

So I hit the internet and did a little shopping to find a digital protractor (angle finder). Found a neat little Klein Tools device and ordered it. It came in yesterday, so I naturally had to run out to the garage to see what was happening.

First, my garage floor has a 1/8" per foot grade which is just over 1" over the 104" wheelbase. In addition, I haven't installed the rear springpack (reversed eye mainspring and a couple leaves removed), so the rear is sitting 2" high. To account for these, I put two 2X4 blocks under each front wheel to simulate the car on level ground. (Hope that makes sense...it did last night!)

Then I moved to the front axle to check caster. The axle is ***embled, so I can't measure off the kingpin, but several checks across the I-beam axle flanges and at the kingpin boss seem to indicate negligible axle twist. And just to verify, I grabbed my steering arm (hoop) from the drivers side and inserted it in the two front holes on the spindle flange (resulting in a vertical orientation and a flat vertical surface to place my protractor). At rest with no pressure on the wishbone, I had a measurement of 83.7 degrees, or 6.7 degrees of caster. BUT...take a look at my wishbone!!!!




I called it quits for garage time and went inside to look at other AV8s to see what their wishbone angles looked like, both unsplit and split. As expected, there were NONE that had a wishbone hanging down anywhere near as far as mine was.

SO...is my wishbone bent at or near the perch pin clevises, or has EVERYONE pie cut their wishbones to adjust for proper placement AND caster? Will a different year wishbone have a more proper clevis angle? (Looking at the photo as I type this...Is my wishbone upside down?)

Any help would be greatly appreciated.

 

My understanding is that the long weld on the wishbone goes uppermost. I can't see a weld in the pics, so possibly inverted as mentioned. Also, there are differences in the wishbone where it meets the axle. Got pix, from front?

Chris

 

Of all the photos I have, this is the best one. I believe the wishbone is upside down! The part of the clevis over the axle at the perch boss should be "level" with the top of the wishbone. On mine, this part is UNDER the axle. Gotta flip it tonight!

 

you have your wishbone on upside down, the tube seam weld goes to the top. that being said, you may still have to piecut the wishbone to get the castor right with a rubber rake. it really will make all the difference in handling and steering, not tough to do just one more thing on the list of things to do on dropping the front end.

 

The welds were different depending on the year of the wishbone. You have yours installed correctly. A’s didn’t have 6 degrees originally. And if you rake the frame it makes it more extreme. You will need to piecut your wishbones a bit.

 

Thanks guys! Another clue would be to look at the yoke. Now that I have had time to inspect the install, I think the curve in the yoke near the ball should dish down instead of up for transmission clearance.

I think my thought process at the time was that the clevis was square with the wishbone tubes and turned the way it is currently would give additional clearance. Novice error!!

 

Go ahead and try putting the wishbone in the other way up. I dare ya. No fair using a torch to heat and bend things.

 

Scout's honor! No torches or welders. Hope I can do this tonight. Plan is...

1. Remove ***embly and check kingpin boss (or axle across-flange) angle with the ball at 9" off the floor.
2. Dis***emble ***embly, flip wishbone, re***emble.
3. Recheck kingpin boss (or avle cross-flange) angle. Compare data.

 

@alchemy is right, your wishbone is in correctly, so used to the later ones where the weld is up that i have split. But yeah turn it over and watch it get real interesting....

 

To keep from dis***embling twice, would I get the same net results if I just flop the wishbone over to where the spring is UNDER the axle? The camber should flip as well, right? Demonstration below....

 

What you show in your photos looks normal.
Wait until you have the car fully ***embled & sitting on it's wheels.
That will give you the actual caster angle.
I say this because, until you establish the ride height & the rake, you are just guessing.
You really can't know what changes to make to your wishbone until everything is together.

 

@brett4christ , your sketch is thinking right, but you've noted the caster angle as camber. Just so there's no confusion going forward.

 

@Pete Eastwood Car is mocked up (see first post). Body is on frame.

Engine is located and weight on front mounts. Rear is on blocks on floor, so half the engine weight is on the front spring. As trans weight is added to the frame, caster will decrease. Axle/spring is located by front crossmember with wishbone attached but unsupported. Original rear is still in (going with a spring-over '40 V8 rear W/ torque tube. Rear spring is reverse-eye and I will remove a couple longer springs to give a little more drop. Floor is graded 1/8" per foot, so 1" over the wheelbase.

With wishbone unsupported, and the axle at 7 degrees caster (thanks @Algoma56 ), the wishbone hangs WAAAAYY down as in the second photo of post 1. If I pull the wishbone up to where I think it ought to be (as compared with photos of other complete cars) the caster disappears/goes to near-zero. As demonstrated in my drawing, I think my wishbone is flipped.

I certainly welcome any and all advice, as I am building in my home garage against a self-imposed timeline...I don't need to do ANYTHING TWICE!!

 

Brett, you need to remember that Henry built the A's a mile high, and level. Now you are dropping the front end, and your spring is way lower. You have totally changed the angles, so you will need to ***emble and get it sitting at final heights before you cut anything on that poor wishbone. The CASTER (not camber as your sketch shows) is measured off the flat ground, and every change you make to the suspension will change the caster. Even putting one size larger tires on one end will change the caster.

 

Note your axle's perches are at this angle /\. The wishbone matches. If you flip the wishbone upside down, the perches will be at this angle \/. But if you really think you need the exercise, go ahead.

 

@alchemy Yes, I understand that these initial exercises are semi-futile, but I need to at least be in the ballpark of where things need to be and how they are oriented. "IF" the wishbone is flipped, better to know it NOW rather than right before I weld the ball mount (or hiem mount if I split).

Wheels/tires are what I "intend" to run. Not to say they won't change, just that's where I'm starting. And if they change, I'll have to factor the impacts they would have on the design going forward.

And if I do the "flop the wishbone over" exercise, it will just be to confirm the wishbone is upside down and how it affects the CASTER! The camber is as you mentioned in your post 15 and cannot change without heat and force.

I'm airing my dirty laundry here to make sure I don't do something wrong that could have been easily avoided by just asking the stupid questions.

Thanks for keeping me straight!!!

 

Your wishbone ( model A , right? ) is right side up , But. . .
One of the most popular methods of A-V8 conversions, uses a narrowed '32 center crossmember.
By doing this, the trans mount , wishbone mount & pedal mounts are part of the crossmember.
Makes this a lot easier, plus the caster takes care of itself.

 

@Pete Eastwood Understood. In my case, I will be using an F1 crossmember which will hold the trans mount and locate the F1 pedals. Hence I'm on my own with the wishbone.

You can see more of my build here:

https://www.jalopyjournal.com/forum...-av8-build-thread.765768/page-3#post-14575722

But, as @alchemy stated, once we drop the front (dropped axle, reversed-eye spring then rubber/wheel rake) Henry's design is compromised, right? It's up to me to re-engineer the setup to get as close to Henry's design (or better) as I can get.

I want to get close with the A wishbone, then move to possibly a 33/34 unit. If that doesn't work, I'll end up splitting a wishbone, probably the A piece, and modifying it to provide the right caster.

 

Your newfangled degree finder is cute, But just putting a carpenter square on the floor works fine too. I put the square on the floor, and up against the I beam. If it touches the beam on the bottom web, and has about a 1/16 to 1/8" gap on the top web, at the front, you are close enough I always figured.

 

@petee: Solid point. Actually, a 'square one' case.

 

Ok, I figured out an easier way to check the wishbone…with my cute little angle finder!

I used my floor jack to get the wishbone as level as I could…ended up hitting the oil pan. So at that position, I measured the angle of the wishbone…4 degrees low from horizontal at the rear (ball end). Then measured the caster at the kingpin boss…also 4 degrees back from vertical at the top. So the wishbone and axle are 90 degrees to each other.

In other words, if I had flipped it over, the measurements would have been the same.

So now, I’ll purchase the 33/34 wishbone and see if that gives me enough clearance to miss the oil pan. I’ll still probably have to pie cut the tubes to get the caster, but at least I know where I am at the moment!

Thanks all for the insight! And keep the advice coming…need all I can get!!

 

A 34 wishbone is much longer than the A wishbone, about the same spread at the rear yoke, and the rear yoke doesn't have a dip like the A does. The front mounts do have more built in caster than the A, but I don't know the angles. A 34 wishbone won't fit on your A axle unless you mill the perch area down to 2", as the A axle is 2.25" tall there.

 

33/34 wishbone will probably be too short.
I believe you'll need a '32.

 

Thanks @alchemy and @Pete Eastwood . With that information, looks like I’ll be splitting the A bones! Budget doesn’t allow a Deuce unit and I don’t need to mill my axle!

Now, do I mount them to the frame or do I try to get them as far inboard as possible?

 

I've done it with a 33-34 wishbone and f1 crossmember like @brett4christ is doing on my coupe about 15 years ago. Obviously the 32 is very close and is about "perfect". But the 33-34 wasn't crazy out there off the f1 crossmember either. I made my own mount and it was roughly 4 inches from the face of the crossmember. I figure since you're building a wishbone ball mount with using an f1 crossmember anyways. You can fudge it with the 33-34 wishbone.

@brett4christ you're definitely gonna need to slice the wishbone like several other guys have mentioned. I'm just finishing up a coupe that will probably need some tuning in that department. Like @Pete Eastwood mentioned in an even earlier post, I tend to adjust caster almost last, with the car completely set up with the wheels and tires I am running, and the entire thing together.

 

@Hitchhiker Hoped you’d chime in!

Quick question though…how did you get around the A spring perch boss versus the 34 perch clevis dimension differences?

 

And if I’m slicing’ and dicin’, can the A spring perch clevises be grafted onto the 34 wishbone? And if that’s possible, can additional length be added to simulate a 32 set?

Stupid questions only if it’s not possible….

 

Yes, you can make the 75.00 model A wishbone work after you make it what you want, and sell the 400.00 34 wishbone to some one who has a 34

 

I see you’re not using a k member, but there is some good information from a post that Mike Bishop put together using a cut 33-34 wishbone with a model A yoke ball. It may be helpful for you to check out and utilize some of the mods he did if you’re still considering keeping an unsplit wishbone and locating it somehow fore of the F1.

 

I've done it several ways. On the coupe I used a dropped 36 axle. On a model T coupe I built on an A ch***is. I had a set if bones that had been heated and opened up to 2-1/4. I found them like that, so I used them. I probably wouldn't do that now.

You could definitely do it by splicing in the A ends.

I think, if I was doing any slicing that involves lengthening as well, I'd just use the A wishbone. I know you can buy new 32 length wishbone arms and yokes as well. Sorta a u weld kit. You could combine that with the model A yoke and ends. That is probably what I would do in this scenario.

https://carrillocustoms.com/products/1932-34-ford-front-wishbone-tubes