looking to see how people have addressed this issue.

I carry anywhere from 300 - 1000 pounds of product in the wagon at a time.
The back seats are in the down position to give me more room.

Over the past 5 years I have had to address the rear of the vehicle with the following:

replaced the rear shocks twice now. looking at a 3rd time.
replaced the rear coil springs once now. looking at going heavy duty.
replace the volvo swaybar with an IPDUSA Swaybar last fall.
replaced the swaybar links every year so far.

Currently with everything out of the car upon visual inspection.
front/rear driver side is lower by 1 inch versus the passenger side of the vehicle.
Also it is looking like the rear is sagging once again.

looking to see if I can do nivomats on the rear (self leveling) or should I look at something different.

Let me know. Thanks.

Hi,

You might want to consider that 1000 pounds of weight is half a ton. Most pickup trucks with a frame are built for that weight. Are to driving on back roads of in some state that just has bad roads. 🤔

If you look on the door tags along with tire pressures you can see what the Gross Vehicle Weight can be.
You subtract the nominal curb weight from that and you find the vehicles capacity for cargo.
This is usually a calculated figure used by manufacturers by assigning 150 lbs. to each passenger.
You do the math tine four or five passengers.
Then you could add an allowance for luggage. You then see why the trunks on cars shrunk or the SUV idea gets crossed up. Maybe that when the marketing called it correctly as being a “crossover.”
Not really excellent for either job but a compromise.

Considering the age of your vehicle I think you are easily exceeding the quality of aftermarket parts.
Especially if you want to retrofit with Volvo minded limits under there. Nivomats really sucked on the 700 series with only everyday usages besides their prices. A Volvo big mistake.

Road dampeners do not increase carrying capacity one bit. They are made to limit the sprung weight loads excessive movements. The heavier springs are wearing out the dampers period. A Vicious circle.

When carrying or moving any mass you are messing with the dynamics of physical motion.
This means, to some extent, an exponentially greater factor of overloading.
You cannot judge a static (sitting) view of the vehicle by looking capable with the seats down.
Any additional loading has to be distributed between the axles.

Apparently the back end is not capable. Any load past the centerline above of axles, front or rear, compounds itself on a suspension.
Too much in the rear of the vehicle affects the drivability of control of the forward motion of a vehicle.
The front end can even become lighter of its designed loading.
Like the allowably tongue weight of a trailer shows up very drastically on a vehicle. Headlight alignment goes to pot too.

You would be better off using a trailer and put that weight over its own a separate axle.
You then will easily see that there was many limiting factors as I suggested.

Phil

Did your car come with Nivomats as standard when delivered? Nivos work with quite soft springs. That means that if you replace them with normal shocks you will get a soft rear end with some sag even when not loaded. I don't know what springs can be spec'd for your car as far as those from the Volvo catalogue is concerned. There is possibly standard to go with normal shocks plus 2 stiffness ratings for HD springs. New Nivos are likely to be very expensive but best if you can afford it and are going to keep what is now quite a high mileage car. The rear IPD arb won't help you much. Don't buy cheap cheap arb drop links. They are known to be short lived. A few thousand miles or 1 year quite usual. Good ones will be at least twice the price