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may want to reconsider the use of the "T" in this application. separate air lines air better. with a "T" system the compression of the airspring in a turn forces pressure to the opposite spring which creates lift. the result is additional body lean. Also, I have had to but a heat shield on the exhaust near the passenger side airbag. the exhaust temperature causes bag seam failure. Air Lift has part for this.
 

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I wouldn't say that connecting the two airbags (the "T" or "tee" fitting fill arrangement) causes extra leaning, but rather it does not resist lean the way separate airbags do. In more technical terms, separate springs contribute to roll stiffness, while a collective spring (such as joined airbags, a centre-pivot transverse leaf, or a "Z-bar") does not make a contribution.

I used separate fill valves and did not connect the air bags because I wanted the air bags to contribute roll stiffness as well as support; however, with the small diameter of the line I am not convinced that there is much difference in quick maneuvers. One installation option would be to put a shutoff valve in the line, opening it for adjustments and closing it to drive, allowing separate operation but single-point filling.

The risk of heat damage is well known for bags of this style, and some of the kits include heat shields, but the Sienna kits do not. I don't think many of us have enough long-term experience with the bags to really know if exhaust heat is a problem; it has not been for me so far.
 

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Anyone have a part number for the airbag kit, I'm trying to find it but can't figure out which one. Also is the Airlift 1000 series the way to go, for my 2008 sienna
 

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As far as I know there are only two brands: Air Lift (Air Lift 1000 series) and Firestone (Coil-Rite product). I think the only difference is in the type of fittings used in the air line plumbing.

For Air Lift, their online catalog shop by vehicle page produces garbage results, but their Application Guide shows (for 2004-2010) a rear kit of 60732 and a rear replacement (just the bags without plumbing) of 60232.

The Firestone application guide shows (for 2004-2010) the kit number of 4155.
 

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I've had mine installed for 3 years. The two bags are linked with a t-fitting. No issues with "extra" body lean compared with the set on my outlander that have separate fills. No issues with -30C winters or +30C summers or exhaust heat.



brian_bp said:
I wouldn't say that connecting the two airbags (the "T" or "tee" fitting fill arrangement) causes extra leaning, but rather it does not resist lean the way separate airbags do. In more technical terms, separate springs contribute to roll stiffness, while a collective spring (such as joined airbags, a centre-pivot transverse leaf, or a "Z-bar") does not make a contribution.

I used separate fill valves and did not connect the air bags because I wanted the air bags to contribute roll stiffness as well as support; however, with the small diameter of the line I am not convinced that there is much difference in quick maneuvers. One installation option would be to put a shutoff valve in the line, opening it for adjustments and closing it to drive, allowing separate operation but single-point filling.

The risk of heat damage is well known for bags of this style, and some of the kits include heat shields, but the Sienna kits do not. I don't think many of us have enough long-term experience with the bags to really know if exhaust heat is a problem; it has not been for me so far.
 

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Where did you guys get your Airlift 1000 kit, i saw amazon selling them for 75 bucks, but wondering if there are any cdn suppliers.
 

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tcp said:
I've had mine installed for 3 years. The two bags are linked with a t-fitting. No issues with "extra" body lean compared with the set on my outlander that have separate fills. No issues with -30C winters or +30C summers or exhaust heat.



brian_bp said:
I wouldn't say that connecting the two airbags (the "T" or "tee" fitting fill arrangement) causes extra leaning, but rather it does not resist lean the way separate airbags do. In more technical terms, separate springs contribute to roll stiffness, while a collective spring (such as joined airbags, a centre-pivot transverse leaf, or a "Z-bar") does not make a contribution.

I used separate fill valves and did not connect the air bags because I wanted the air bags to contribute roll stiffness as well as support; however, with the small diameter of the line I am not convinced that there is much difference in quick maneuvers. One installation option would be to put a shutoff valve in the line, opening it for adjustments and closing it to drive, allowing separate operation but single-point filling.

The risk of heat damage is well known for bags of this style, and some of the kits include heat shields, but the Sienna kits do not. I don't think many of us have enough long-term experience with the bags to really know if exhaust heat is a problem; it has not been for me so far.
tcp,

I have a 2007 Sienna with a 2" Curt hitch. When the van is loaded, the bottom of the hitch is 3" from the ground. I was looking for something more permanent then the airlift because I read some other forums where they deflated after 7 months.

I'm in Minnesota and I was worried about how the airlifts would handle the cold weather. I see from your reply above that I shouldn't have to worry. What pressure do you keep your airlifts at?
 

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I generally keep the bags at 10-15psi without the trailer attached. Keeps the sienna's butt at a proper stance.

I had the air leak out one time and it was due to the valve stem inside the schraeder fill valve unscrew itself. I tightened it up and it's held the air pretty much indefinitely now. Calgary winters haven't caused a problem and never snagged a line even though they exit under coil. They're tougher than you'd expect.
 

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Hi guys. I am new to this forum and to the minivan world. Twins put me in the Sienna! I just picked up a 2011 LE and really like it. I had the dealer install the factory hitch and wiring. Normally I do all that myself but I just don't have the time. The Toyota hitch looked like it was the "lowest" profile (most ground clearance) which is why I ponied up the extra $$$.

Anyway, my boat trailer is very heavy (3500 pounds) and thus the tongue weight is way up there - not sure but based on the rule of thumb it should be in the neighborhood of 350 pounds. I know all kinds of folks are gonna flame me saying that it is too heavy for the Sienna, but I believe it will be just fine. I came from a 2009 RAV4 Sport V6 (essentially the same engine and towing capacity) and it pulled awesome.

My problem is rear end sag. And more precisely a lack of traction. I found that pulling the boat up a steep gravel hill resulted in some trying moments. It took 3 tries, and a good run for me to get up that hill (should have gone for the AWD :'().

I think I will end up getting airbags no matter what to alleviate that sag, if one the manufacturers finally brings one out for the 2011. But I am wondering if you think that it might help with traction. I am thinking that if the ass end doesn't sag so much, thus pulling the weight off the driving wheels, that maybe it would help.

Thoughts??

Thanks guys.
 

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Unfortunately, air bags have no effect on the transfer of load from the front axle to the rear in response to the force pushing down on the hitch. They allow the rear to sit at closer to the original height by providing more spring stiffness to support the load on the rear axle, but they don't change that load or make any difference to the front.

A boat does not usually run as high as 10% hitch weight, and even if it is that high, adding 350 lb to the hitch only prys about 150 lb off the front axle, which is not a major thing for traction (compared to the 2700+ lb it starts with)... but there still might not be enough traction for some circumstances. AWD is the real answer, but the only way to shift load - and traction - to the front axle with towing equipment is by using a weight-distributing hitch (WDH). WDH use is much less common with boats than with travel trailers, in part because most WDH designs interfere with the operation of the surge brakes which are commonly used on boat trailers (and only very rarely on travel trailers).
 

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Like Brian said, the bags won't help with the traction issue and it is a good probability you can't use a WDH with the trailer. The bags will help with the rear sag though. I'm not familiar with the the stock Toyota hitch. Is it a 2' receiver or a 11/4"? If it is the smaller receiver, you may be approaching the load limit for the hitch as many 11/4 receivers are only rated to a max of 3500 if it is a class 2.

One thing you may do is check your actual tongue weight to determine where you are. If it is excessively high, you may see if you can adjust the boat on the trailer to move it a little further back. Depending on the trailer and the boat, even moving it back a few inches can have a dramatic effect on the tongue weight. Just be sure that you don't lighten the tongue too much. That may help with the traction a little bit by not transferring so much weight from the front wheels.
 

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Good idea, p220sigman. Before radically changing the towing gear, see if the root cause of the problem can be addressed.

Another interesting characteristic of boat trailers is that many can be adjusted, changing their configuration - axle placement, tongue length, boat position - to suit the boat and tow vehicle.
 

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I really didn't think the bags would help, just thought I would toss it out there for a collective thought. The hitch is only 1 1/4", which concerned me enough to ask the Toyota guys if that was really up to the task of 3500 pounds. They say yes, so here's hoping!

I have never weighed the tounge, just the entire boat/trailer. The tongue is HEAVY though - I can't lift it myself. I thought about adjusting the axle to shift the weight, but the trailer config doesn't really allow for it. My old boat trailer did though and I did just that in the past.

Hopefully the scenario I described (steep, gravel roads) are rare. I don't move the boat around too much anymore anyway, but I would like to be sure that I am comfortable when I do take it on vacation or whatever. The airbags are going to go in regardless though, as soon as they are available.

Thanks for the feedback.

Eric
 

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rfcc150 said:
I have never weighed the tounge, just the entire boat/trailer. The tongue is HEAVY though - I can't lift it myself.
Remember that the air bags do not increase the load capacity of the vehicle, only help it handle that load better. The tongue weight limit is 350 lb for some reasons, and without making any assumptions about those reasons, it still applies even with the air bags installed. The ability of the air bags to mask the tongue weight by restoring stock ride height regardless of load makes it even more important to determine the actual tongue weight and ensure that it is appropriate.

I can't lift even 200 lb, so "heavy" may still be well short of the 350 lb limit!
 
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