1948 Chevy Leaf Springs

Tech Question - 1948 Chevy Leaf Springs

Dear Mike,

I have a 1948 Chevrolet Fleetline Aerosedan two-door; lowered three inches in the front by one inch shorter coils and two inch dropped spindles, and lowered four inches in the rear by two inch lowered reverse eye flattened springs and two inch lowering blocks.

My problem is this: the front and rear ride height is OK, but the rear springs are starting to arch upwards between the U bolts and swinging shackle, and the U bolts and front chassis mount, which in turn is opening gaps between the leaves.

There are no clamps around the leaves.

The front of the rear spring, under compression, is rolling on about two inches of the main leaf against the chassis rail.

I can only suppose that, under full compression, the springs and mostly the main leaf, are separating as they arc upwards.

Is it possible that you can supply a pair of springs without reverse eyes, that will give me the same ride height and ride quality without the problems above and that I could possibly discard the lowering blocks or replace them with one inch blocks?

I intend to replace the lever arm rear shocks with telescopic adjustables, but need to sort the springs before I fit them.

I am in England. The car is right hand drive, if that makes any difference.

Thanks for your help.

Regards,

Sean

Sean,

You describe the classic shape of a spring that has had leaves removed from it.

The 1948 Chevys used a 7 leaf spring for the coupes and an 8 leaf spring for the sedans.

Each and every leaf in a spring is important. Not only does each leaf carry a proportionate amount of weight, they also provide support for the leaf above it and the leaf below it.

The weight carrying capacity and load bearing support is changed when leaves are removed. The shape of the spring changes from "a curve" to "a wave" when enough leaves or the wrong leaves are removed for the spring. And "wave" sounds like what is happening to your springs.

So how many leaves are still in your spring? The amount left is important in order to build you a set of springs that will do as you wish.

You can learn more about what happens when leaves are removed at our Tech Page, and also download a copy of Spring Tech 101. We also have information available on lowering blocks.

-Mike