Do you happen to have any pictures of your setup? I have been dreaming of a very similar build and would love to see how you accomplished it.

Thanks guys! It sounds like I'm going to go with cones and hi-los. As usual you've all been awesome and super informative!

Spax and Gaz (and probably other brands as this is not a new idea) do rear coil over shock kits that will fit without having to do any body mods. I tried this conversion many years ago and have never been back there since on any other build. Even with the shock wound down to the lowest setting ride was still quite harsh. Wheel arch is only designed for a shock, to control suspension bounce, not to carry the entire weight of vehicle and any additional load. So, mods are advisable such as stitch welding arch to load floor and additions strengthening where coil over bolts through top of arch.

Hard to beat the good old rubber cone setup I would say. My suggestion would be a set of new rubber cones and some hi-los. This would allow you to raise the rear of the vehicle when carrying larger loads and still have compliant suspension with a decent amount of travel.

True: the body weight and live load is carries on the 4 corners of the subframe which in turn transfers the load to the wheel and ground. (Ditto the front end.) The shock absorber's job is to keep the wheel assembly from bouncing up and down.  Malsal is right that coil-overs won't fit into the vertical channel for Mini rear shocks. The channel must be larger and moved in-board to maintain clearance of the coil from the wheel and tire. The steel-work of the wheel arch would also have to be strengthened and modified to distribute the forces into other body panels.

You should find out what the maximum design load capacity is for a van. Springs and ride height are just the beginning. There are many other factors to consider, such as braking ability, strength (under dynamic loads of driving) of things like wheels, wheel studs, axle shafts, swing arm stiffness and strength (including its mountings).

I thought of suggesting a trailer. Haynes reports that the weight of trailer for a saloon is 404 kg but only 303 for  estates, vans and pick-ups. Tongue load is 45kg  (100 lbs). Maximum roof rack load 40Kg (88lbs). These weights include the trailer and/or roof rack itself.

I read somewhere where the coil over shocks do not have enough clearance in the shock tower to fit correctly. The solution is to cut out the tower and install bigger ones (maybe Mini Tec sells them). this was a while ago and maybe now there is a solution for the problem. Could you just fit air shocks or adjustable ones?

I hope you are using Odyssey batteries and not old school lead acid. 

The upper shock mounts are not intended to carry the weight of the car, so there is no sort of easy solution to your weight carrying that involves parts normally sold for race cars, like coil over shocks.

I would buy whatever brand of hi-lo style adjustable trumpet you like and then put the junk in and on the car and sort out the ride height with new cones.

The van specific shocks are for the van type rear suspension with its longer trumpet, which in turn makes for a longer shock travel when unladen.

Thank you Mur for the reply. The van including the 2 passengers will be carrying around 900 lbs, we outfitted it to more or less turn it into an RV. There is a roof rack with a solar panel, basket, driving lamps, awning and Thule rack with kayak J hooks weighing around 120 lbs., the 2 kayaks on the roof together weigh around 150lbs., a wood platform and foam mattress in the back weigh about 50 lbs., backpacks, climbing gear, camping gear and 3, 12V batteries weigh around 250 lbs. and then the rest is the 2 of us. The weight is dispersed as far in front of the rear axle as I could. So were the trumpets the only difference between the van and a saloon? I see Spax sells van specific shock absorbers as well...

I will start by asking how much weight you will be carrying, and why, what is the nature of the weight, etc.

vans and wagons had slightly longer trumpets to allow a greater payload.

original hi-lo trumpets had a wider face that met the rubber, and this then influenced stock parts, the bell of the trumpets from the start of MK IV or so became bigger as well. This change made the rubber springs more adaptable to heavier loads. 

Actually carrying more weight will wear the rubber out faster. Original van trumpets with new rubber cone springs will make the vehicle sit quite high at the back, this will then settle, and of course as the van is used and carries weight you may want to adjust the trumpets longer to regain the load carrying ability.

An important part of the mini's actual success is that it is a 1500lb car that can carry 4 adults and some luggage. You don't see big SUVs carrying 1/3 again their weight. This is all due to the progressive nature of the rubber suspension.

Hi guys, I was wondering if anyone here has tried the Spax Coil-over kit RSX519 in a panel van? Or perhaps could recommend something slightly heavier duty for the rear suspension so I could put a fairly significant amount of weight in the back. Would race rubber cones be a good stiff option? Thanks again guys for your help!