Since the van builds are not that heavy (7,300 Its.) I've removed the "helper springs" on all my van builds. They create a smoother ride, lower the back of the van down to almost level and improve the handling on curvy roads.
Thank you to Nurse Ben
for his earlier draft of the instructions. Here is my updated version:
Removing Secondary Leaf Springs on a ProMaster Van
I've been pondering removing the "helper" leaf springs for a few years. The ProMaster Forum has had a number of posts about it. If your gross vehicle weight is a lot less than the max, this is an option. It lowers the back of the van to be basically level with the front, so it looks better from the side view. It makes the ride a lot less bumpy. It lowers the van height at least 2.5 inches. It corners a little better.
To do this project, I’d recommend two people and it takes about two hours.
You will need shorter bolts to replace the leaf spring centering bolts. I used 3/8" x 1 1/4" grade 8 bolts/nuts with fine threads.
Don't even attempt this without a ½" drive - 2' long breaker bar to loosen and tighten the U bolt nuts and a 22mm deep ½" socket plus a 1/2" drive ratchet to remove and reinstall the nuts. A 7/8 deep socket can work also, but either of these are not a very common size in your tool sets.
Using the factory jack, working on one side at a time, raise it up until the tires are about 3 inches off the ground. Then add a strong jack stand. We also used 2 - 4 x 12s for the jack base. One the second side we added the jack stand and base and then left the factory jack in place as a backup support.
Loosen and remove u-bolts and hardware, unclip emergency brake cable from axle, pop off wires holding cable to the top of the leaf springs.
Clean the treads on the u-bolts because you will be using more of the threads after removing the extra spring.
It is not necessary to remove the shock bolts.
Remove the nut from leaf spring centering bolt.
Jack up the axle until the springs begin to lift from the spring perch
Then the secondary spring and centering bolt can be removed.
Reinstall shorter centering bolt.
Jack up the axle until bolt head is resting on spring perch.
Reinstall the u-bolts on both sides.
The tricky part is getting the bolt head back in the spring perch hole. On one side my helper pushed with his feet from the back of the van the tire forward. On the passenger side we used a floor jack to hold up the axle and a small sledge to tap it into alignment. This is where it helps to have two people.
Reverse everything, then repeat on the other side.
I can definitely tell the difference in ride. I got about a 2 ½" drop in the rear. Now the rear is only ¾ inch higher than the front. The bumpers are only about an 1" from the top of the spring, whereas before they were about 3'. The ride is not as bouncy and softer now.