It's alot easier to just put the truck on jackstands, remove the coils, install the airbags and reinstall the coils. You're going to have to remove the coils anyway because you need to cut 2 pucks off the conical bumpstops to give the airbags space to work.

 

My dad has airbags on his Dodge 2500 Cummins and his 97 K2500 Suburban for towing/ hauling heavy loads. They work great. He had the airvalves run to the the filler neck for the gas tank, hidden and easy to get to. He also found that a decent bike pump is the best way to fill them. Get a bike pump with a built in pressure gauge, and thats it. Air bags hold very little volume and can be overfilled very easily with an electric pump, and the bike pump is easy to take with you.

 

Yep, the bags can be folded up enough to just be squeezed in between the coils when the rear suspension is fully extended. This gave my air bags a bad case of "stretch marks'. but that didn't seem to matter, as they lasted at least 5 years with zero problems. Obviously if you have to pull the coils to remove the bump stops, that's the time to install the air bags. But if you don't, it probably saves 1-2 hours doing it my way. The bump stops on my '98 were external to the springs, and were easily removed.

I have to respectfully disagree with the poster who said your truck will be on the bump stops even with air bags with a 1,000# load. I don't think that's so, as balancing my 400# trailer tongue weight took only 17 psi in the bags, and they're rated for 35 psi. I believe Air Lift rates the bags for 1,000#. That said, I'm not sure I'd want to drive a 3rd gen 4Runner very far with the extreme rearward weight bias that a half-ton load will create!

At the time I installed the Air Lifts, there were many posts claiming that air shocks would worsen the ride far moreso than air bags, as the air shocks use a much smaller bladder and require much higher air pressure to achieve the same lift. I have no experience with the air shocks, so can't attest to this, except to say that the Air Lifts had a very modest effect on the ride.

Good luck.

 

I agree with khaug, the airbags are what holds the weight at that point, not the stock springs. And there are no bumpstops, as they are removed when installing the coils. On my dads cummins he has a 2" spacer upfront so the truck is level when empty, when loaded he loads the truck and hitches up the trailer. The bed probally has 2000#'s, and the tought weight is probally 750-1000#'s, he then pumps up his air bags with the bike pump and he is back to level... the airbags support a very large percentage of the load, the stock springs carry a fair amount, but probally not most. Air bags are essentially springs, semis dont have regular springs, for the most part, they have airbags.

 

Karl, I actually agree with you that the airbags could be pumped up hard enough to support the 1000lbs in the rear but I guess you essentially said what I was trying to say......if the airbags were pumped up to enough pressure to have the 4runner sit level with that much weight, the ride would not be the safest thing in the world. Could it be done, the answer is yes.

 

What is not safe about it? Certainly MUCH safer than riding on the bumpstops, and the payload of a 4runner is 1365#'s so you are safe there. The airbags will keep more weight on the front tires, which helps braking and steering, and at night keeps the headlights off of mars. There are many HD rigs that only have airbags.

 

John, I take it you haven't tried driving with alot of weight back there (we're not talking your dad's cummins here). Try putting 1000 lbs back there on a 3rd gen, hop out on the highway and try taking an off ramp. I am telling you that is alot of weight and the truck doesn't handle anything like it does normally. I am not saying don't get airbags or that airbags don't work if that's what you are implying (in fact I will likely be running airbags soon and yes, they are definately better than stock.....I don't think I ever said otherwise). What I am saying is you need to really be careful when driving that heavily loaded is all.

The 1365 lbs total payload includes occupants (so the weight will be distributed across the front and rear springs much better than if it was all in the back of the cargo area) and try putting the full amount in the back end of a a stock 3rd gen 4runner and see how it does. I think Toyota is completely out to lunch on that number (without stipulating that it must be evenly distributed).

 

I actually already have put 1000lbs in the back of it and it did OK. Mind you the place I get the pellets from is up the hill from me about 10 miles. Power isn't an issue and the weight is only back there for maybe a half hour. I also did cheat a little and had the back seats down and loaded as much as I could in the middle of the truck. I also put a few bags on the passenger side floor and went solo. I didn't look to see if I was on the bumbstops, so I can't comment on that. It's definitely not something I'd do very long or often, that's for sure. I still need to attach my camper and take it for a spin. It doesn't weigh much but when you load the truck up with gear and two dogs I'm sure it could use some help. I think for $100 air bags is definitely something I'm going to conceder.

Other then that I'm loving my 4runner! I've had pickups in the past and I could use 4 doors and better gas mileage far more then a bed.

 

That's not cheating, it's just smart......the more you distribute the load the better it will ride. It also helps if you're just driving on surface streets rather than a highway or taking corners at speed. If you are going to carry stuff like that the airbags will defintely help. There are quite a few people running them (and probably myself soon as well).

 

I have had almost 2000 pounds in the back of my runner and towed a 1700 pound trailer, on 285's, with a 22RE for about 1300 miles. That is one experiance of a lot of weight. I have towed a 5K pound trailer all over the mountains and highways of Idaho and E Montana. I have had so much weight I put a hitch haul in my front receiver to add 300 pounds to the front axle. Its still safe, but as with any rig loaded to or a little beyond capacity, you have to be smart about it. I wish I had airbags when I have had my 4runner loaded beyond capacity, it would have made it safer.

I have also had 1300 pounds of cement bricks in the back of my 4th gen an barely noticed it.

The GVWR is designed on what the vehicles axles can handle, to include safe brakeing. The GVWR on a 99 is 5250 pounds, there is then a 3500 tow rating. The 4runner is designed to safely handle with a vehicle weight of 5250 while towing 5000 pounds. Your correct that it is better with even weight distro, but 1000 pounds throughout the cargo area, espically with airbags will still be safe and very driveable.

I also think you would be suprised how easy it is to reach 1000 pounds, I am sure than there are many 4runner owners that have exceeded the GVWR of 5200 pounds and never known it. My 95, with just my tools in the back, weighed in at 5300 lbs, after susp lift, leaf swap, 33 TSL's, ARB bumper, etc. And it drove fine at max GVWR and when it was 2000#'s over it drove fine too, braking was increased, and cruise speed was reduced but I was still able to drive safely.

 

That's scary......

I've had mine way overloaded on the tongue weight and the drive was so bad/dangerous I had to turn back and hire someone else to move the stuff. I never measured the weight but it had to have been 800 lbs plus and the trailer was probably in the 5000-6000 lbs range (again these are just guesses since I did not actually put them on a scale.....although I probably should have). I probably could have done it with better gears, airbags and Tundra brakes up front but I could could feel it was an accident waiting to happen (felt like driving a boat, very unresponsive, hard to turn/stop/accelerate so I just called it quits). I'm only stating my experiences and if people want to throw 5 tons in the back of their 4runner and tow it around, then go for it.

 

I agree about being way overloaded on the tounge. I use a 11" drop hitch and when the tounge is way overloaded it takes too much weight off the front, which is why i had that 300lbs on the front receiver. Air bags would be so great there because it keeps a bunch of the weight up front, just like a weight dist hitch.

 

Wow, good discussion guys. I won't be doing that kind of hauling at least for very long. I do tow a wakeboard boat about a mile or so back to my place but thats about it. Like I said the main hauling I do is of firewood and camping gear, so hopefully it should be fine for that. My rig is only a 2.7L so really slows down when towing the Mastercraft.

My bumpstops are not on the inside of the coils, they're on the outside so yeah hopefully that will make it easier.

Thanks for all the great advice guys!

 

So are the OME 890's the same height as the 99's coils in the rear? It sounds like another option would be to go to these which are stiffer? Thanks!

I found this site which looks like there are even stiffer springs then the 890's

http://www.wheelersoffroad.com/ome4runner.htm

 

No, they are definately going to ride higher.

All with P265/70R16 tires on a 4WD 4Runner (stock bumper, no extra weight in cargo area):
The 99 coils should sit at about 35.50-36.00" from fender to ground
The OME 906's should sit about 36.00-36.50" fender to ground
The OME 890's should sit about 37.00-37.50" fender to ground

The OME's are definately stiffer than stock in the rear.
The 906's have a spring rate of 270# per inch and the 890's are 300# per inch (not sure what the rate is on the 99 coils).

 

Looking at that site there's 890, 891 and 892 which get progressively stiffer the higher the number. I wouldn’t care if the rear was up an 1in or so from where It’s at now. It’s a little lower than the front right now. Would it ride poorly if I kept the 99 front springs but went to 891’s in the rear? FYI the springs and shocks were replaced by the previous owner less than a year ago with the 99 springs and Tokico trek master R/T’s. It’s a 2000 sport with 265/70/16’s which I plan on going up one size with. I’m just looking for more rear support. Air bags are still an option but it would be nice to not have to mess with it every time I add weight to the back.

Thanks for everyone’s replies and sorry for stealing the thread a bit!

 

If you put 891's on there with 99 coils up front, you'll look like you're ready for the dragstrip. With 99 coils up front you'll be about the same as 881s in height (about 0.5" shorter) and it will look pretty much like mine does right now.

 

Sounds like the air bags are a better option at this point. Thanks for your help!

 

I'm going to give the OME906's a try and see how the stance/ride is.
If I like how it drives, then I'll probably add airbags for occasionally carrying heavy loads.