I have a 2007 Toyota Sienna Minivan. Recently, I added a Class III trailer hitch, so I can tow my small boat & trailer, (1000 lb). Because the Sienna is so low at the rear, the hitch/draw bar hit bottom while traveling over uneven terrain. The shock absorber companies don’t seem to have a load adjusting shock available for this model. Putting a Class IV or V hitch,(load leveling), on might make matters worse. I’ve thought about adding helper springs to the stock shocks, however these shocks have plastic skirts. (Ain’t plastic wonderful ?) Adding an air leveling system,(if available) would be costly. “Buy another car or truck !”, you say ? No thanks ! I’m running out of ideas. What do you think ?
You probably should have gone with a class II hitch because they are lighter and the back would not be sagging as much. This is a case where over-engineering is not the way to go.
The best solution for this problem are inserts for the rear springs. They are air helper springs that insert inside the coils. You mount the filling tubes out of the way and the valve in a convenient place for filling and bleeding our air. You just pump them up when trailering and let pressure out to the minimum level when unloaded.
Ok, your van has a tow rating of 3500# (according to the dope provided on the ‘research cars’ link on this website).
I checked Reese and Draw-Tite hitches and only the class #3 fits your van.
There shouldn’t be more than 10% of total load weight on the tongue at the hitch.
If the load (including the trailer) is 1000# then 10% is 100#.
There is no way THAT weight and the weight of the hitch itself (55#) should make the rear sag as far as you claim.
The rear shouldn’t sag more than 2".
You may have the wrong draw bar.
Use one that when you place it in the receiver reversed (upside down) will allow the van and the trailer to sit level.
If you are using a 2" to 3" drop type bar, invert it and see what you come up with.
Just change the ball to the opposite side.
Let us know how you make out.
Thanks for the suggestion, however the draw bar I use is alraedy in the rise,(4"), position, because I have to compensate for the low rear end to keep the trailer level. Reversing the draw bar would probably cause the assembly to drag on the pavement. The weight of the trailer does not cause the rear end of the van to drop very much. This minivan just has a low clearance at the back,(as compaired with my old Dodge Grand Caravan which was higher and that I was able to install a Class II hitch on). If I’m not mistaken, Valley makes a Class II hitch for this vehicle, but I’m not sure a Class II hitch would make much of a difference. I might be forced to go with the air bag system.
Toyota seams to be doing things right except…eh?
They ought to know better.
Use air shocks and put the valve in a convenient location in the back of the van, perhaps in a storage compartment (jack?).
Put air in to raise the rear to where you want it, but remember to release the excess air when you don’t.
Note: these air shocks aren’t outrageously expensive and are not considered a ‘self-leveling’ system.