2004 Lx470 AHC Firestone air bags NOW AIR LIFT (1 Viewer)

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Joined
Nov 2, 2014
Threads
10
Messages
179
Location
Richmond VA
My goal is to have my LX470 with AHC tow ready.
First I checked the pressures with techstream via amazon and then I changed the AHC fluid with the correct Toyota product.

After seeing my pressures were increased I had to decide NEW AHC or some components (coils) or new OME or add 80 series spring, or augment current system (airbags).
I chose the airbag route b/c it will be reusable in most other systems once I change to them in the far future. For now, I need to stick with the stock system b/c I like it and b/c I already paid for it.

I did some cursory airbag research and found the Firestone kit with a pretty easy to follow downloadable 4124 instructions here. I like the Firestone kit b/c it has the "no drill" option. If I do not have to drill into my vehicle I prefer not to. Also, drank the koolaid on they were the first ones to ever make air supsensions so they must know what they are doing.

I have VERY LIMITED MECHANIC experience but felt since I had worked on a suspension once before, I could do this. Here is my one word of caution. Working on suspensions is dangerous, if you haven't done it before, do not start by yourself, do it with someone who knows what they are doing the first time you do it. There were many times I had to hit the brake and remember I was working under a 3 ton vehicle on jack stands that I was pushing and pulling on.

OK, anyhow, with my limited experience I decided I could do the task if I was careful not to get myself killed and I took my time.

First I assembled my tools the night before b/c I knew it was going to be a pain to do it by myself and I wanted as much prepared as possible.

I highly recommend having 4 x 3+ Ton jack stands if you plan on doing this in a private garage. I also used a 3.5 ton jack because it had more "lift" in inches than the 4 ton option.

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During the process I discovered I needed this equipment as well.

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I followed the directions almost word for word except while the vehicle was on the ground I loosened all bolts that were going to be removed. Other deviations included, I disconnected the wrong end of the battery and I didn't remove items after loosening them. This made the experience much longer than it needed to be. I had to jack all components back up and knock them off with a mallet because they were still in place.

After jacking it up and putting jacks stands FORWARD of the axles,
I loosened the bottom nuts of the shock. (No pic, you know what the shock looks like).
Then I had to loosen the sway bars (forward of the axle).

swaybar.jpg
 
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and loosen the drivers side of the PANROD, behind the axle.
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and loosen the E-brake cable in the middle of the axle.
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Then I followed directions on how to get one side lower than the other to make it easy to remove the coils. Not really "easy", I spent an hour trying to figure out a way to get the drivers side coil to drop free. No dice. I knew I could pry it out, but I was worried if I pried it out, how would I get it back in, well, it easily pushed back in, so that is some time I wasted as well. Ironically when I went to do the passenger side, it literally fell out when I went to grab it. LULZ

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Here is a photo for the perspective of how long the coil gets when not compressed and how small the airbag is in comparison.

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Next I had to remove (12mm) and cut the bump stops.
They recommend using a vice, so that is what I used.
cutbumpstops.jpg
 
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After cutting the bump stops and assembling the bag into the coil and routing the hoses. This is what it looks like installed in its new home.
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After both sides were installed. I had to move the jack and jack stands around back and forth to get all the suspension to line back up with itself. The mallet again became an essential part of the process.

At normal height compression the bags sit tight and there is no space in there.

I mounted the nozzles to the plastic bumper b/c it is easily accessible and right next to the cigarette lighter that I use to run my air pump.
Valves.jpg


I pumped the bags to 10psi.
My rear pressures are now lower with me sitting in it, with the REESE hitch.
pressures.jpg

I will adjust the PSI and TB's next and get all values where they should be. I started the project at 0745 and ended at 1245. Not including clean up. I am pretty spent so when it came to cleaning up or typing it up, I chose typing it up. LOL, now to go clean up the mess.

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Had some time at lunch today to adjust TB's and PSI.

As for PSI adjustment:
I let air out of one side to get it equal to the opposite side of approx 9-10 PSI.
For TBs, I Jacked her up onto jack stands and clockwise turned the TB's 3 complete turns each.

Resultant pressures:
Update3.jpg

Ideal is (6.9+/- 0.5) front & (5.6-6.7MPa) rear.


Final appearance of bag:
Update1.jpg


Another perspective of fill valves:
Update2.jpg


The bags are rated to be 5-35 PSI.

With the airbags I believe there is a little more feedback with the rear wheels and the road than before. But I suspect I may be imagining that, so I am not sure. It is a still very comfortable for a "truck" that tows.

As for when I tow I will fill the bags up to 20-25. If the AHC has a problem with that I can always crank up to 30-35. I am really happy with how this turned out.

She will get an alignment before I drive too far.
 
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Nice work in the install and write up. What do you tow? You shouldn't "need" and alignment as a result of adjusting the TBs, as the height sendors should retain angles with the AHC. Good option for those that load gear, people, and put a lot of weight on the hitch.
 
Great writeup. I will look into these as well.

I have OME 865 now and they are great, but when I load up for a trip I drop 2" in the rear. Air bags seem like another solution vs going to a higher rate spring that will ride rough unloaded.
 
Had some time at lunch today to adjust TB's and PSI.

As for PSI adjustment:
I let air out of one side to get it equal to the opposite side of approx 9-10 PSI.
For TBs, I Jacked her up onto jack stands and clockwise turned the TB's 3 complete turns each.

Resultant pressures:
View attachment 1026636
Ideal is (6.9+/- 0.5) front & (5.6-6.7MPa) rear.
The bags are rated to be 5-35 PSI.

With the airbags I believe there is a little more feedback with the rear wheels and the road than before. But I suspect I may be imagining that, so I am not sure. It is a still very comfortable for a "truck" that tows.

As for when I tow I will fill the bags up to 20-25. If the AHC has a problem with that I can always crank up to 30-35. I am really happy with how this turned out.

She will get an alignment before I drive too far.
Try and use TechStream to dial in your rear pressure/air bag inflation psi when you're fully loaded up with trailer etc. Just sticking 20-25 psi in without knowing what that's doing to your neutral pressure might not be optimal. While your experimenting with the best pressure to ride comfort ratio I'd increase your rear pressure from 5.6 to 6.0 or so, you're at the absolute bottom end of the permissible range and slightly higher pressure may actually perform better. Good job.
 
Did you have to permanently cut out the bumpstops or do they unbolt somehow?
 
Do you have a picture on how your lines are routed and protected assuming they come out of the top of the bag as pictured. I have run a couple sets of AirLift and the bump stop needs to be removed and the line comes out of the bottom.
 
Nice work in the install and write up. What do you tow? You shouldn't "need" and alignment as a result of adjusting the TBs, as the height sendors should retain angles with the AHC. Good option for those that load gear, people, and put a lot of weight on the hitch.

Excellent. I will not rush to align it. I have some other things I want to do first. That is great news. I tow a 16" V-nose enclosed trailer filled with various supplies and a large locked tool box.

Great writeup. I will look into these as well.

I have OME 865 now and they are great, but when I load up for a trip I drop 2" in the rear. Air bags seem like another solution vs going to a higher rate spring that will ride rough unloaded.

I "think" it would work with a 2" lift. It came with some "spacers", I bet thats what they are for! I was all finished with the install, looked in the box and thought WTF, what are those spacers for? I bet that is the answer. It would definitely help it from bottoming out.

EDIT: After thinking about this further you could just cut 2" less off the bumpstop and it should work just fine.

Picture of possible spacers added:

spacer.jpg


Try and use TechStream to dial in your rear pressure/air bag inflation psi when you're fully loaded up with trailer etc. Just sticking 20-25 psi in without knowing what that's doing to your neutral pressure might not be optimal. While your experimenting with the best pressure to ride comfort ratio I'd increase your rear pressure from 5.6 to 6.0 or so, you're at the absolute bottom end of the permissible range and slightly higher pressure may actually perform better. Good job.

You got me!! I was trying to be lazy, but I have done 95% of the work to make this possible, so it makes the most sense to get it maximized out and find out the exact PSI (especially b/c the trailer weight is pretty consistent). Now that I think about it, I could knock it out at lunch b/c the trailer is right there to tinker with.

Did you have to permanently cut out the bumpstops or do they unbolt somehow?
The bumpstops unbolt out with a 12mm bolt. Then you cut them down. Then you route the hose through where the 12mm bolt used to be. Then you take your old 12mm bolt and throw it in your tool box for future random usage. Here is an image from the 4124 instructions linked at the top of this thread.
answers1.jpg




Do you have a picture on how your lines are routed and protected assuming they come out of the top of the bag as pictured. I have run a couple sets of AirLift and the bump stop needs to be removed and the line comes out of the bottom.

With these bags the lines come out of the top. Look at image above. I chose this system specifically because it is a "no drill" system, and Firestone is well established. It appears from my research the other brand is more used on IH8MUD, so I made sure to share my experience here, so people will know their options. I don't have a picture, but I altered the 4124 instructions pdf image to show you how I routed them. It basically runs from the TOP of the coil springs to the top of the frame. I kept it well away from the exhaust as that will probably be the biggest problem. I didn't see anything up there that looks like it moves so I think the hoses are safe where they sit. If not, I will update this thread if I have to make any changes to the current hose routing. The passenger side is where I was worried about the exhaust, so I ran it to the drivers side and ran it next to the drivers side hose until they hit the bumper. I can try to take pics if you need them, but I just zip tied them to the frame.

answers2.jpg
 
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Keep us posted on durability. If you don't ever flex your rear axle, you might be ok for a while. Search some of the air bag threads on here for my experience with durability of routing through the top hole and also exhaust issues. BTW, the spacer is to protect the barb.

Edit: https://forum.ih8mud.com/index.php?threads/369256/
 
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Keep us posted on durability. If you don't ever flex your rear axle, you might be ok for a while. Search some of the air bag threads on here for my experience with durability of routing through the top hole and also exhaust issues. BTW, the spacer is to protect the barb.

Edit: https://forum.ih8mud.com/index.php?threads/369256/

I will let you know if there are any problems.
No this is not a full articulation rock crawler, its a moderate trail, tow and family van.
Thanks, looks like good info at the link.

Now that I have done it already I will have no problem going back in there and flipping them upside down or whatever need be.
Time will tell. Next time I go in there I will put new LX coils too!
 
Update time:
So I finally got to tow with the 100.
zzz1.jpg



9-9.5 psi consistently gives me good readings of AHC pressures with No tow.
zzzNoTow.jpg


After hooking the trailer up the AHC REAR pressure numbers rose out of recommended range as expected with the added weight:
zzzheavy.jpg


So I pumped the air bags up to 22-22.5 psi per bag and got the pressures back into range:

zzzheavyFix.jpg

Just an update. The bags are a nice "peace of mind". I suspect the vehicle would have put itself into low mode without the bags being at 9psi at initiation. Since the vehicle is somewhat "perfect", I suspect it may be the reason the previous owner let it go, (all speculation on my part) because I really don't know why the previous owner would let this vehicle go.
 
Another update/addition:
Someone previously requested to see where the air lines were routed.
I dropped my spare tire per my auto detailers recommendation to maximize pressure washing effect and found that I could see the air lines much easier. Took some pics for those who wanted to know.

BTW I recommend dropping the spare tire to put air bags in. It would have been much easier to route and see what I was doing had the tire not been in there when installing the bags.

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You sir deserve the award for the cleanest udercarriage I have ever seen on a 100 series. I know it was just washed but still very impressive cleanliness. I almost feel a little guilty about mine... almost... :D
 
You sir deserve the award for the cleanest udercarriage I have ever seen on a 100 series. I know it was just washed but still very impressive cleanliness. I almost feel a little guilty about mine... almost... :D

Wow! You can say that again.

Great write up too!
 
Its been about 7 years and the system is no longer working right. Pinched lines, I think one of the bags is leaking. 7 years is not bad, but I have added weight, with bumpers, etc.
Now, I am switching over to King Springs with the Airlift system. Just waiting on the King springs to arrive from Aussie land.
 
Finally got my springs, reaking of Vegemite!

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I like them!!
 
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This is great! I had airlift on the back of my 80 and I loved them. I’ve been thinking about adding them to my lx470 too.

Thanks for the write up!
 
I find less is more in terms of bag pressure vs ride comfort. I'm also running the king springs, plus 30mm spacers, and airlift bags. The ride gets a bit bouncy over speed bumps if there's even a bit too much air in the bags. I think that's because without a lift, on a larger compression of the suspension, the bag is being squashed top and bottom and raising the pressure, so there's more rebound than the AHC can handle. Give the AHC a bit more work to do, and it handles damping that much better and also handles the pitching a trailer can cause much better. If I need H, I put a bit more air in to help it get up there. I think shorter air bags would work better for standard height AHC. Just my experience, ymmv.
 

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