I ran a string front to back on center and also marked the position of the front axle. I clamped one spring in place to get an idea of where the spring will sit. The plumb bob is about 1/2" behind the axle center line as the center should move about that when the weight is on. This is not the final placement of the spring, it is moving closer to the inside of the frame for tire clearance when turning.
-- Edited by henrys57wagon on Thursday 26th of March 2015 05:04:49 PM
Not trying to criticize your work and plans but most guys cut off the frame at the firewall and use 2X3 or 2X4 tubing. Easier, cleaner and less weight.
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Custom CNC plasma cutting. PM me for your custom parts.
No problem Mike. I have some 2X3 already, but I don't want to remove the frame at this time. Quite a few cars I have looked at have done it the way I am.
Glenn, thanks for sharing your knowledge. I'm certain the rest of the folks here appreciate it, I know I do. Sometimes builds can go horribly bad because the builder didn't think to ask others when venturing into virgin territory and while we've never met in person yet, I'm equally as certain no-one remains a virgin for long with the Cat around, lol.
Thanks again, first time doing it, straight axle(no box trailer involved). Very good info. Would you have the springs wider at the front or the back? The more I think of it I might just cut off the front frame and weld on tubing. After all it is my retirement project. Any more pic's or a link to the Falcon build?
I think you got some great advise there, especially the part about not finishing the welds on the shackles or the spring perches on the axle.
It's hard to estimate exactly where they should be until you get the full weight of the car sitting on them.
By the way, when you finally do fully weld the spring perch to the axle don't do what I did. I welded them on really quickly with the full weight of the car sitting on them and the heat and weight caused the axle to bend a little. Next time I'll weld a little more slowly.
One more thing,,, some gasser style cars look good with the axle moved ahead a little from the stock position. (like about an inch or two)
It's easy to do when you're installing a straight axle so you might want to look at some Henry J pictures to see if it might look cool on your car.
Love those Henry Js, especially in gasser trim! Looking forward to see this project. You can't go wrong with the advice on this forum. Experience is gold! Good luck with the build and keep us posted.
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I'd rather be in the garage! I'm old school, I use the "inches" side of the measuring tape!
I like to run more caster angle because it gives more stable handling,less wander. Just look at a top fuel dragster axle (extreme) .You can use shims once its on the road to fine tune the angle. I have found that any little thing can change the handling on a straight axle-tire type,size ,inflation,toe-in, how the rear end is mounted etc etc. Just keep adjusting until you get there. Once everything is set up they work fine.
I swapped my Falcon to a buddy with a straight axle Fairlane for a day a few years back. The Falcon is on the ground, the Fairlane was sky high. Long story short, I pulled onto the street, nailed it, used up both lanes, both shoulders and part of an orchard before I got it stopped. Beautiful car, TONS of horsepower but handles like a rubber ball in a puddle of snot. Too little caster ?
I swapped my Falcon to a buddy with a straight axle Fairlane for a day a few years back. The Falcon is on the ground, the Fairlane was sky high. Long story short, I pulled onto the street, nailed it, used up both lanes, both shoulders and part of an orchard before I got it stopped. Beautiful car, TONS of horsepower but handles like a rubber ball in a puddle of snot. Too little caster ?
Make sure the front wheels are straight and you are on flat dry pavement or things get exciting real fast. That's why gassers are so much fun,like I said, any little thing out of wack. An independent front end will mask all manner of sins , a straight axle will amplify them.
I swapped my Falcon to a buddy with a straight axle Fairlane for a day a few years back. The Falcon is on the ground, the Fairlane was sky high. Long story short, I pulled onto the street, nailed it, used up both lanes, both shoulders and part of an orchard before I got it stopped. Beautiful car, TONS of horsepower but handles like a rubber ball in a puddle of snot. Too little caster ?
Make sure the front wheels are straight and you are on flat dry pavement or things get exciting real fast. That's why gassers are so much fun,like I said, any little thing out of wack. An independent front end will mask all manner of sins , "a straight axle will amplify them".
Yup, it did all of that, lol. I grew up sliding sideways at speed so that part didn't excite me any. I just didn't want to have to fix it before we traded back. I'd actually like to do a straight axle under our Comet along the way.
Almost every single big truck on the road has a straight axle. These trucks steer just fine even on bush roads. When you think about it, most of the 3/4 ton 4x4's have straight axles too. My last Jeep had a straight front axle and my new one has independent suspension. The new one rides a little better but the difference isn't all that great. As long as the axle is installed properly and the alignment is good, it should steer just fine.
Caster is important, that's what gives you that nice planted feel,,, like you can let go of the wheel and the car will want to keep going straight. 5 or 6 degrees is usually enough but some guys like to bump that up closer to 8 or 10 degrees on a lighter car. (my 55 Chevy steers fine with about 5 degrees)
If you're using a cross steer linkage,,, like going from the pitman arm across to the passenger side, you should be able to have very little bump steer. The ideal setup would have the steering linkage parallel with the axle at ride height, but most of the time the linkage is running down hill, like the drag link in the picture below. Anyway, try and get it as close to level as you can but if you end up with an angle similar to the one in the picture, it'll still be fine. You might also notice the damper in the picture. You don't always need one but it's not a bad idea to put one in right off the bat as you're building the axle setup. Performance Improvements sells a nice little Volkswagen style damper. It's a SoCal Speed Shop part and it comes with brackets.
-- Edited by jim_ss409 on Monday 30th of March 2015 08:32:09 PM
-- Edited by jim_ss409 on Monday 30th of March 2015 08:33:03 PM
Almost every single big truck on the road has a straight axle. These trucks steer just fine even on bush roads. When you think about it, most of the 3/4 ton 4x4's have straight axles too. My last Jeep had a straight front axle and my new one has independent suspension. The new one rides a little better but the difference isn't all that great. As long as the axle is installed properly and the alignment is good, it should steer just fine.
Caster is important, that's what gives you that nice planted feel,,, like you can let go of the wheel and the car will want to keep going straight. 5 or 6 degrees is usually enough but some guys like to bump that up closer to 8 or 10 degrees on a lighter car. (my 55 Chevy steers fine with about 5 degrees)
If you're using a cross steer linkage,,, like going from the pitman arm across to the passenger side, you should be able to have very little bump steer. The ideal setup would have the steering linkage parallel with the axle at ride height, but most of the time the linkage is running down hill, like the drag link in the picture below. Anyway, try and get it as close to level as you can but if you end up with an angle similar to the one in the picture, it'll still be fine. You might also notice the damper in the picture. You don't always need one but it's not a bad idea to put one in right off the bat as you're building the axle setup. Performance Improvements sells a nice little Volkswagen style damper. It's a SoCal Speed Shop part and it comes with brackets.
-- Edited by jim_ss409 on Monday 30th of March 2015 08:32:09 PM
-- Edited by jim_ss409 on Monday 30th of March 2015 08:33:03 PM
Thanks for the info. This is a great topic, lots of seat-of-the-pants experience. I've driven a few straight axle cars, some handled terrific - others could be a handful. I've driven through a bad wobble only to have it smooth right out eventually - and I've ended up in the rhubarb too, lol. I'll be picking a few fella's brains here before I switch the Comet.
