Technical Help me identify axle set up in my A Roadster

Ok, last week I bought a '28 Roadster on what is believed to be a '31 frame. The body is actually just an original cowl with a nicely home made body. Right now I'm in planning phase and trying to figure out how i'm setting the car up beginning with the front axle. I've done a lot of searching and haven't found any pics or explanation of how mine is set up. It looks like this set up lowers car almost 5" which I like. I haven't noticed others with the axle behind the springs though? Will this handle ok and be safe? As you can see there is a Vega box on there I was planning with sticking with but I do also have a f100 box. For what its worth the rear is set up with an 8" Ford axle with some nice pockets welded on frame for coil overs.

 

Oh yeah, I plan on cutting off the bracket that looks like it was for a panhard bar. Not sure why that would have needed up front unless it was driven this way and had some issues and they were trying to correct.

 

Would not this shorten your wheelbase ? Seems like it will open a whole lot of fitment issues for fenders
etc.

 

This set-up was fairly common on '50s and early '60s built rods. Very limited axle-to-frame clearance.

What you've got is Model A axle, '37 to '41 Ford spindles, and wishbone/spring perches. This set-up moves the axle back about three inches and on full fendered Model A's it looks really goofy.

 

Yes I would think so. Not gonna run fenders or a hood so have fitment to worry about, more concerned about how it affects the ride/handling.

 

Not enough info on the rest of the chassis and what wheelbase it has now. Spring-ahead was done a lot to get the car lower without a dropped axle, but if it was used with a stock location front crossmember, the wheelbase gets shorter.

If your builder moved the rear axle back, and moved the body back, the car might look proportional.

I happen to like old builds with spring ahead,(I have one) ... but I never saw an A axle before on a spring ahead, and I don't really like the look. It would look way better with a dropped axle IMO...but it's not my car

 

So will the frame to axle clearance be an issue? Thanks for filling me in on some of the components I have on there.

 

Welcome to the HAMB. Nice start ya got there...

We run a Vega box on our roadster. The original one was a low quality junker in the beginning which wore out over couple years. Wandered all over the road! Replaced it with a new quality box from a reputable supplier and it steers nice now. So be sure to check your box if you decide to use it. I liked the set up because, if done right, there's no bump steer...

You should probably get a copy of the Bishop & Tardell book.
How to Build a Traditional Ford Hot Rod. You will learn a lot and be inspired at the same time - I know I did.

 

the axle is A and the spindles `37-`41 , but i believe those wishbones are `35-`36

 

Thanks for the welcome! I thought it was a decent starter rod. I've built and owned many muscle cars and trucks but never a hot rod, so this is my first go of it. It looks like this would be a simple set up with the Vega box so if it'll work I'd like to stick with it. I like the ride height but don't want to sacrifice proportions and want it safe.

 

In theory, a spring ahead can be made to ride better than a spring above. As you probably know, a long leaf spring will ride softer that a shorter spring on the rear of typical rear drive cars.

You can deal with that later in the build by using spacers on top of the spring if needed.

You have almost no weight there yet.... and I see a problem. Your shackle angle looks perfect for a finished car with all weight on it. Once you finish your car, and maybe soften the spring by removing some leaves, the shackle angles will be really bad. Either a shorter "eye to eye" spring, or perhaps a later axle that has a wider perch pin location, or mess with the spring hangers with heat/bend. I'd consider swapping to a 33-36 or 37-41 I beam if it would fix the shackle angle. I'd be measuring things to see what will work

 

So car is tucked away in dark carport next to garage but just got a rough wheelbase measurement.... 103". It looks to me like rear axle was moved back about 7". Looks like spring forward set up moved axle almost 4" back. Do all these numbers sound right?

 

F&J, excuse me for maybe asking a dumb question. Can the wishbones be swapped side to side and a longer spring used eye to eye? Probably ride softer than going shorter on the spring. I see what your talking about though and just bouncing on frame with my weight I can see how the shackles move to a more verticle position.

 

If you switched the wishbones side to side; you might find the eye to eye dimension matched one of the common aftermarket '28-'34 springs. Probably also have to heat and twist the eyes to get them square with the axle again.

Edit- didn't type fast enough again

 

Spring In front set ups showed up in 1935. The perch pins on the 37-41 axle are wider.

It's hard to tell from the pics, but if you split the 35-36 or 37-41 wishbones (yours are split) the perches hanging over the front move considerably closer to each other. It's pretty easy to get the little bit of twist out to square up with the spring but moving the perch back to its starting position to maintain its original center to center is a bit more involved. If you split the bones and don't move the perch you'll need a custom shorter spring as the original will be way too long. - your spring is too long

 

I'm sorry for being such a newbie. I don't know what you mean about split bones. I understand what you are saying about the later axles having wider wishbone mounting locations.

 

Don't be sorry for that
Everyone was a newbie

The wishbones actually look like a wishbone in their original form, joined at the rear, mounted in the center of the frame. Note the hangers are actually some place between the perch pins and the king pins.



Can you see how splitting and moving the rear end further apart will also move the perches closer together

 

Got it, so since these are split somebody must have moved the perches to square them up with the springs. I clearly see how a shorter spring is the quickest solution to this. How about switching the bones side to side and running a longer spring? Is this even a possibility?

Seems as though, just eyeballing it this would spread the perches out by 5" or 6".....requiring a spring 4" or 5" longer eye to eye.

 

Measuring springs has a bit of poetic interpretation to it.

These are mounted in pre load tension & quite a bit. That has got to be figured in. Then reversing the eyes changes things, removing leaves and letting a spring flatten changes things too.

When its said and done and road ready the shackles want to be at a 45* angle \ / . That's what you shoot for but as the arch flattens the eye to eye gets longer and the shackles move towards vertical. The closer to vertical, more theoretic problems arise.

You could try swapping the bones left for right, just be careful. Springs in tension can ruin your day

 

I used the same combination of parts on my Roadster.. or at least, '36 bones. They may be '37 if they haven't been shaved to fit the Model A axle, or the axle has been shaved to fit. The '32 - '36 axles are 2" wide at the boss whereas the earlier Model A and '37 onwards are 2 1/4".

I used a 3" dropped Model A axle, with '36 bones split.. and i cut the hangers off. I currently have Model A perches with a spring OVER the axle. I need longer perch bolts or i can have the top of the wishbones machined down about 5mm and have the 60 degree taper recut.

If i were you, i'd cut off the spring hangers.. find an Model A spring, have the eyes reversed, send that axle off to be dropped and bolt it all up as a spring over axle setup like it had from the factory so that you retain the original wheelbase.

Edit: You already look to have Model A perch bolts with the shackle holes. As you can see in the other picture the later ones don't have shackle holes in the perch bolt.

 

This picture gives you an idea of what i've got going on, if you replicate it.. it's a great setup.

It's a Model A axle, 3" drop, stock Model A spring with reversed eyes, stock Model A perch bolts, '41 - '48 stub axles with dropped arms, '36 bones split (you're wishbones shape wise are the same) out to the frame rails. I found i didn't need to have those big ugly long wishbone mounts that the guys with Model A wishbones need. The '36/'37 just seem to flow right up to the rails nicely when the axle is at about 6 degrees of caster.

Edit: I should probably note i'm building a RHD car, so my steering box is on the other side. I'm doing a cross steer with a '41 Ford box and it's mounted exactly like your Vega box is but on the other side.



Here's how i mounted the wishbone to the chassis. I used a weld in Speedway bung, a bit more modern adjustable rod end and made up this bracket. The pipe is just a piece of bar drilled to the same size as the bolt for a really nice fit. Hope this helps.

 

Do some serious homework before you get in too deep- when you set your front end up, there's a specific set of geometric rules you have to adhere to with an old style front end. If you use " split bones", your rear mounting plates have to be long enough that you can maintain a 5-7* pitch outward off the front face of the axle, or it's going to cause problems. Lots of HAMBERS in NH and some real talented builders/ rodders among them ( there's a bunch here in Mass. too- hell we're everywhere!) Welcome to the club, and keep asking questions; like they say "there's no dumb questions, just dumb answers!" ( and you may get a few of those ).---- And check out the new "Candia Swap" (there's a thread on here with directions , it's right off 101)- last Sunday every month at the Bleven's Farm. Lots of HAMBERS go, and there's lots of Model A stuff for sale . Neat farm, nice folks, and good buys.--- Good Luck!

 

28A, your set up looks great. Yes my A perch bolts do have shackle holes so I could go that route. I do have about a 103" wheelbase currently though because rear axle has been moved back, so I have near stock wheelbase now. My body will be moved back on the frame.

Mike bowling, thanks for the tips. I'm guessing the 5-7* your talking about is the caster angle measured off the face of the axle? My rear mounts hang down pretty low so I will have to check to see if I have that caster angle and adjust accordingly if I go that route. Yes, I know about the Candia swap and plan to go to it. I actually know the guy who puts it on son. Good people.

 

Yes on the caster- I stick a magnetic angle finder right on the front face of the axle ( I don't use tube axles- looks too much like a T- Bucket!) Biggest thing on the "bones" and axle caster is to make sure you have enough adjustment once you've got the engine weight sitting on the front end. I always either clamp or tack weld everything till I'm pretty sure it's right, and use tie rod ends, not rod ends ( to avoid binding). Time to do your homework! The truth will come out the first time you drive it! They almost always need some adjustment, no big deal. See you at Candia!

 

This one has threaded rod ends on the end of the bones. It looks as though all this was set up some time ago, so hopefully it's been down the road with this set and just needs minor adjustments instead of complete 're-engineering.

 

Go for it!

 

So far this site has been great and I thank you all for commenting.

So to sum things up to make my current configuration work I need to confirm proper caster and proper shackle angle.....likely resulting in the need for a shorter spring eye to eye. My rear axle has been moved back maintaining proper 103" wheelbase, so with body moved back proportions should be good. If any of this configuration does not work than its onto some of the suggestions given to me.

One more question, thinking I should run shocks, where's best spot to mount them?

 

Post pictures as you go- helps us here in the audience to understand better what's up. Looking forward to your progress reports. Good Luck.

 

I'm still skeptical that the proportions will look correct, even though the axle has been moved backwards.. and the body will go backwards.. the front end will look awful. The wheel base will be correct but because the axle is moved backwards, you'll end up with the radiator and grill sitting on top of the original cross member as per factory but the axle will be behind it, instead of underneath it.

This seems like one of those "just because it works, doesn't mean it should be" things..

Hold on.. i just had a thought. You haven't shown us how the rear end is set up. Is there a stock Model A crossmember with some rear end and a spring in front of the rear set up going on to get the rear end further back? If so i'd ditch it in favor of a spring over setup, or move the crossmember forwards get the axle back where it should be in relation to the front crossmember to realign everything where it SHOULD be.

 

Rear is set up for coil overs.