The Promaster 3500 comes with some super heavy duty springs rated for 5000lb payload and the ride stinks and the van is pretty raked out from the factory. It’s a 15 minute job to remove the secondary helper leaf spring, which both lowers it 2″ as well as softens the spring. Not sure what the new spring rate is, but lots of people that make these campers do this, as do all the buildout companies using the Promaster as their platform.
It was such a piece of cake I didn’t take any pictures of doing the actual work
1) Disconnect rear swaybar
2) Jack up via axle
3) Put on jackstand
4) Remove 2 U bolts holding the springs
5) Lower axle, remove secondary
6) Raise it and reconnect the U bolts
Took me about 45 mins total for both sides from start to finish. The van looks a lot better and also drives better. Definitely less jarring on sharp edge hits on the road.
Didn’t take a good before pic, so here’s someone elses with the rear all jacked up.
And here is the after pic of mine