Quarter to Semi Eliptic Spring Conversion

REAR SUSPENSION MODS
Quarter to Semi Eliptic Spring Conversion

The obvious first. You'll need a set of semi-eliptic springs with rear shackels and mounting brackets. A semi back axle, complete with back plates and hand brake linkages.

Now you need two peices of box section. The size will be dictated by the space available. You need to cut across the full width (cut the side with the seam) and down both sides until your just into the flat of the sides. If you stop cutting in the radius part you'll never flatten the lugs out and will tear the steel trying.
Now cut down the middle until you get to your first cut. Then open out the two sides and straighten and then weld the places where your saw cuts ended, drill the spring pick-up hole and shape the two lugs.

Then these need to be drilled and slotted down the sides so the box can be bolted in where the old quarter eliptic was held. The U bolts should be ok but you'll need new bolts at the front.

This next bit may not be required as a lot of rear floors have been replaced with later ones. Although if this is the case it's still worth checking diagonal dimensions to see if everything lines up.

Next you need to drill 6 holes for the rear shackel mounts, this is a case of measuring 2 or three times and check diagonals from the front pick-ups. Get these wrong and your car will crab! You'll need to make up some doubler plates and weld into the floor and hopefully add something to take the loads back to something firm.
Some people have welded a cross member between the two plates?

This all requires a lot of measuring and remeasuring and a trial fit or two. Nothing complicated just time consuming. But it will pay off. Check the heights all around you may need to make packers to go between the Shackel mounts and floor or the box and floor to get the best level and don't forget you can use different springs or lowering blocks between the spring and axle to get the ride height you want.
If you don't take the time to get everything lined up you may have a car that crabs.

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Now you need two peices of box section. The size will be dictated by the space available. You need to cut across the full width (cut the side with the seam) and down both sides until your just into the flat of the sides. If you stop cutting in the radius part you'll never flatten the lugs out and will tear the steel trying. Now cut down the middle until you get to your first cut. Then open out the two sides and straighten and then weld the places where your saw cuts ended, drill the spring pick-up hole and shape the two lugs.
	Then these need to be drilled and slotted down the sides so the box can be bolted in where the old quarter eliptic was held. The U bolts should be ok but you'll need new bolts at the front.
This next bit may not be required as a lot of rear floors have been replaced with later ones. Although if this is the case it's still worth checking diagonal dimensions to see if everything lines up.
	Next you need to drill 6 holes for the rear shackel mounts, this is a case of measuring 2 or three times and check diagonals from the front pick-ups. Get these wrong and your car will crab! You'll need to make up some doubler plates and weld into the floor and hopefully add something to take the loads back to something firm. Some people have welded a cross member between the two plates?
This all requires a lot of measuring and remeasuring and a trial fit or two. Nothing complicated just time consuming. But it will pay off. Check the heights all around you may need to make packers to go between the Shackel mounts and floor or the box and floor to get the best level and don't forget you can use different springs or lowering blocks between the spring and axle to get the ride height you want. If you don't take the time to get everything lined up you may have a car that crabs.