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Author Topic:   Multi leaf spring position
ss#4
Member
posted February 19, 2004 11:55 AM
Okay,

I have reviewed all the tech setup articles I can find and spoke with Afco Tech (Landrum is too busy for tech questions). And I am still having difficulties. I have the front mounts in position, but where should the rear mount be positioned?? Distance horizonatally from front eye and vertical from bottom of frame or ground would be perfect. Also what is the most friendly way to load the leaf to position? I am working with a bare chassis only the weight of the frame.

Ego Racing
Member
posted February 19, 2004 12:24 PM
Try Landrum's web site they have some Killer guides t go with. www.landrumsprings.com
Then go to the technical area.


ss#4
Member
posted February 19, 2004 12:38 PM
Thanks I looked a little closer on the site and found the dimensions you mentioned.

Now any good ideas on preloading the spring into position?

Ego Racing
Member
posted February 19, 2004 07:35 PM
Not on a leaf. It would put it in a bind. To pre load it you would need a solid rear mount. You could use an excentric mount on the front, this would allow you to slightly alter the front mount location and put a little load in it.


ss#4
Member
posted February 20, 2004 05:54 AM
No my concern is how to pull the rear eye down to the mounting position. In the free state the rear eye sets about 10" higher than the "mounted" position. What is the best way to push the leaf into position and still have front teeth when I am done?


Ego Racing
Member
posted February 20, 2004 07:53 AM
IS the chassis sitting on the spring? Can you jack up the chassis? The spring should not be loaded unles the chassis is sitting on it. If you have the spring bolted in the rear mount and the rearend bolted to the spring you should be able to jack up on the chassis and to should almost fall into place.


ss#4
Member
posted February 20, 2004 08:40 AM
Ego,

here is a zoom of the area. your are right when the chassis is raised and the axle contacts the underslung and does lower the rear eye, but I am still 4 to 5 inches away from the recommended position of 17.5 inches from the ground.

Dman
Member
posted February 20, 2004 10:57 AM
An underslung rear with leaf springs is a challenge. From what I can see the rear of the springs is way to high. The difference between front and rear mounts should be kept under 9 inches. The BIG problem is if you lower the rear of the springs it is going to put more of a bind on the springs because it will raise the front.
The other option is to raise the front but then you are going to change the weight tranfer because the chassis will think the spring is "taller" and you are getting the mounts above the chassis weight center which will cause no weight transfer.


madmodshoe
Member
posted February 20, 2004 11:06 PM
Is it just me or are the shackles not even hooked up in that picture? Yes, running an underslung is not recommended for leaf springs.


Ego Racing
Member
posted February 21, 2004 11:00 AM
They are upside down and the bolt is threw the spring. The mounts are not going to last with being in single sheer.


racing north
Member
posted February 21, 2004 04:16 PM
ss#4 HERE The shackles are just hanging. I took the pic to show the free position of the rear eye of the spring. The red X is the approximate position the eye needs to be pushed down to acording to Landrums mounting points.

The spring is 53inches eye to eye giving it approximately a 7 inch arch. So in the pic you can see the spring would need to be loaded in order for it to get there.

Can anyone tell me the arch of their spring when installed with weight on it? This way I can understand roughly how much the leaf may deflect and in turn grow in length.

racing north
Member
posted February 21, 2004 04:19 PM
EGO, can you explain why the mount will fail? I will have a 1/2" bolt through both the spring eye and shackle on the bottom and another 1/2" bolt at the frame pivot. What am I missing here????
thanks SS#4


Ego Racing
Member
posted February 21, 2004 08:51 PM
You must mount the bolts in a double sheer mount. In the picture the bolts are in single sheer, mounted like this it will bend instantly when you put the chassis weight on it. It should be mounted Through the chassis frame rail with the shackle on each side and the spring under the rail or you will need to add a brace to the chassis and out to the exterior shackle to help distribute the weight.
Also the shackles are mounted upside down the single hole by itself is for the chassis. The other holes are for the spring.
With the underslung rear you are going to have to force the spring down into the mount.
At the Landrum web site I told you about they show you how to mount the springs. If you are usng the Chevy multileaf the rear mount should be 53 inches behind the front mount. If using the Chrysler style the rear mount should be 54 inches behind the front mount. To tell which you have the chevy style has the locating pin about 20 inches from the front spring mounting hole while the chrysler are about 25 inches back.


Ego Racing
Member
posted February 21, 2004 08:54 PM
Almost forgot: on the chevy style the rear shackle mount, frame pivot point, should be 12 inches above the front mount. On the chrysler it should be 12 inches above.


racing north
Member
posted February 22, 2004 07:21 AM
I know the shackle needs to be above the eye and that the shackle frame pivot should be in front of the rear leaf eye, so it has some angle to it and not 90deg to the ground. I also have the print out from the landrum site showing the same positions you have sited. But when I swing the leaf into position (54" back and 12" up)the shackle angle is to the back not the front. I only want to know how much the leaf should push back when at ride height with the weight of the car.

Would someone with a leaf car be willing to measure the distance from the front eye to the rear eye and the height to the rear eye in a car that is ready to roll on the track??? If that is not possible could I get a Left rear corner weight so I can load the leaf as it will be mounted? Thanks SS#4

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