I need this measurment as seen in pic, it's a 32 frame and I am using a 40 front spring. Please help. Thanks.
The length of the unspung spring is 39" center of eye to center of eye. I was thinking that measurment would change with the spring under load?
My '40 Ford rear perches are 48" apart, but since you're using a '40 front spring, I'm thinking that you want the front axle perch distance. That looks to be 42". Got a spring spreader?
The spring shown in your pic looks to be too long. If vertical travel is sufficient, the spring will have the shackles shoved way over before the car hits bottom. Here's a few pics that should give you an idea of how the spring should look. What you're seeing is a 40 Ford spring pack less the top two and 2nd leafs. Along with a custom made main leaf. Measurements between spring shackle brackets is 44" Any spring shop should be able to knock out a new main leaf for you. If it would help I can measure the length of the spring main leaf along the curve and post it later.
The '40 rear I have is 48 1/4" on center. The front mounts on the wishbone are 40 1/2", and the spring eyes are 39" on center with stock shackles.
Thanks alot fellas. 37Kid, I think that's the measurment I need, because the spring I am using is 39" unsprung. C9, it would help if you could post, because I noticed in one of the pics that it is the very same pic in "Shop Rag" issue #1 summer 2002, nice job on that BTW. I will be going over to Just Dug's place today and do some measuring on his 32, I think he is using the same setup. Thanks again everyone.
Well after the BBQ at Dugs I found out that all the cool kids are using a model A rear spring. Here's a question, is there a formula for this? Gotta be, Henry had one. For example, if you have a 32" spring, then the distance between the perches should be X". If it's a 39" inch spring than the distance should be Y". How does one determine that in the first place?
To go along with the 44" bracket spread, here's the spring measurements. 41 3/8" eye to eye measured straight across from one eye to the other. 42" eye to eye along the curve which would be the same distance as it would be if the spring was flat. The pic shows the spring bracket mounted to the outside of the frame. The rear axle is 56" measured outer drum to outer drum.
Aren't these cars using the stock rear crossmember which allows the A spring to sit higher in the chassis? If you used the A spring in conjunction with your flat crossmember the car would sit too high.
You Sir, are correct, and yes I do understand, I am not using the stock rear cross member or an A rear spring, using stock 40 front spring with flat cross member is what I am using in the rear. Thanks for all the replys.
I,m using a 40 front spring on the rear of my A Sedan and had the same problem. Just how do you work out where the perches go? And how much preload should you put in the spring? I worked it out (I think) by removing the main leaf from the pack, measuring the perch center distance then compressing it flat and measuring again. Then halved the two measurements and used that to determine where to mount the hangers.I ended up having to spread the spring 2.25" and it looks ok but I haven,t put it under any load yet as I,m still building the rear part of the chassis. I dunno, was I right? Was I wrong? I guess I,ll find out when I finally get some weight on it.
It works pretty well to mock-up the front end with main leaf only. Make a block - wood is fine - to duplicate the height of the remaining spring stack. In an engine-less, no transmission chassis, mount the front axle, spring U-bolts etc. where they go. Connect the radius rods/wishbones/4 bars. Add wheels w/tires. The chassis with body on will sit very close to finished ride height. You don't need to worry about radiator, hood etc. Body weight will get you where you want to go. The same should work in the rear and along with a ride height check you'll be able to see about where your spring shackles end up.
Well it sure pays to search for info when here when you need it. I am putting the rearend in my new Roadster project and I am using a 40 rear spring and need to figure the spacing for the spring hangers. Well to my surprise I'm not the only one with this situation, and the info here will be very helpfull. Jay your setup looks great and is exactly what I am doing. But I do have one question, you say you had a custom main leave made, is it the same width as a aftermarket reverse eye spring like the ones that posies sells? That is what I have, I guess I'll go back out to the garage with the measurements you provided and see what mine actually measures.
I just did this shit yesterday on my model a project,K-member the first pic you posted is a 40' front spring,39" center on the spring eyes,you will have to spread the spring to 39 1/2" to put on the shackels.The spring hangers will have to be 42 1/2" center to center on the rearend,with the spring installed the shackels should be straight out,until weight is applied then they will angle down.The front springs are 2" wide & the rears are 2 1/2" I think.I built my own hangers,out of plate steel & 460 ford wristpins.I had to cut them to 2" & grind the ID a few thou.& the new shackel bushings fit tight.I bought my new shackels from C.E. & they look like they are built out of good stuff,I also have used speedway shackels but they are not as heavy as the C.E.ones.Hope this helps some guys.I will try to get some pics.
O damn, sorry I sould have posted the progress, I figured it out with alot of help from C9 and had it done about two and a half weeks ago. Got these really cool cast patent pend brackets from Marshall and mounted the spring on them. I had to hand fab every bracket, but I like doing brackets, none of Jefferys mail order shit worked, all for the better I guess....Here's some pics. O Yeah, after closer inspection the spring was a wide one so it turned out to be a 39 Merc rear.
cast spring perches? bolted to little tabs welded on the axle tubes? sounds like a recipe for broken spring perches. henry used forged only. every setup I've seen welded to an axle used a bracket that covered about half of the axle tube.....
Spring width is 2 1/4" fwiw. 44" bracket spread. 41 3/8" eye to eye measured straight across from one eye to the other. 42" eye to eye along the curve which would be the same distance as it would be if the spring was flat. The aftermarket main leaf is from SoCal. Last I heard they don't sell the main leaf by itself anymore. I would guess it's close to the Posie's main leaf far as length goes. Their recommendation on bracket install width/distance would give you a good idea of how long the spring main leaf is.
GREAT POST! I'm at this same stage in my project and somehow I missed this? k-member= Does Marshall plan on selling these brackets?? I like the look of them. I plan on mounting my rear spring soon and will need to make brackets. C9 = Great info!
No! Marshall had those very old really cool spring hangers laying around forever, never seen another pair. And for all I know they could be forged, I do know they are pretty heavy duty. I don't think they will fail, should be as strong as any other welded on perch.
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