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FITS 2002 Toyota 4Runner
Firestone Coil-Rite Air Helper Springs - Rear Axle

Firestone Coil-Rite Air Helper Springs - Rear Axle

Item # F4135
Our Price: $125.90
Vehicle Suspension
Confirmed to Fit
2002 Toyota 4Runner

4 Wheel Drive Models

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Vehicle Suspension F4135 - Air Springs - Firestone
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The best technical support and full vehicle suspension installation instructions. Great price 4Runner vehicle suspension and expert service. Toyota 4Runner, 2002 vehicle suspension by Firestone are available from For expert service call 1-800-940-8924 to order your Firestone Coil-Rite Air Helper Springs - Rear Axle part number F4135, or order online at
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2002 Toyota 4Runner - Firestone Coil-Rite Air Helper Springs - Rear Axle

  • Air Springs
  • Rear Axle Suspension Enhancement
  • Firestone
  • Light Duty

For safety and stability, air springs are the perfect partner for your rear suspension when you are hauling heavy loads. Springs fit inside existing coil springs to help level your Toyota 4Runner, improve braking and handling, and reduce tire wear.


  • Provide extra support for your existing rear coil springs
    • Fit inside existing coil spring suspension on your vehicle
  • Keep your vehicle level when you are hauling a heavy load
    • Improve steering control and balance
    • Level your headlight beams
    • Reduce tire wear
  • Maintain even load distribution with air pressure, leveling off-center loads
    • Air bags adjust manually, side to side, with individual inflation valves
  • Enable more effective braking and handling
    • Work under heavy loading and adverse road conditions
  • Increase stability to promote a smoother ride and prevent bottoming out
  • Made of durable, elastic polyurethane for years of comfort and stability
  • Include all materials necessary for installation
    • Brackets, air springs, hardware, air line and separate valves for manual inflation
    • Switches and gauges, compressors, and air tanks (sold separately) are available for quick and easy air spring inflation/deflation from inside your vehicle
  • Made in the USA


  • Load-leveling capacity: at least 500 lbs (at most 1,000 lbs)
    • Coil-Rite springs will not increase your vehicle's weight-carrying capacity. Do not exceed the manufacturer's recommended weight limit.
  • Adjustable air pressure: 5 psi to 35 psi
  • Limited lifetime warranty on air springs
  • 2-Year limited warranty on hardware

Firestone Coil-Rite Air Spring Basics

Firestone Coil-Rite springs fit inside your existing rear coil springs to maximize the effectiveness of your suspension system. The added cushion provided by the air springs allows your vehicle to better handle a heavy load or trailer. Hauling heavy loads or towing a heavy trailer can make the rear of your vehicle sag and the front end rise. This puts more strain on your rear axle and reduces contact between your front tires and the road, causing problems with braking, steering control and traction. By adding air springs to your rear suspension, you can help to level your vehicle for more effective braking and handling under heavy loading or when you encounter adverse road conditions. The air springs also help to level your headlight beams and reduce wear on your tires.

Firestone Coil-Rite airline installation

Adjustable Air Pressure

The air pressure in your Coil-Rite springs can be adjusted manually, side to side, to compensate for off-center loads. A centered load improves the stability of your vehicle by reducing body roll. The air springs will also help to absorb road shock and soften contact between your axle and frame. This prevents bottoming out, thus improving ride comfort. Route the air line tubing for the springs to your vehicle's bumper to provide easy access to the manual inflation valves.

Firestone Coil-Rite air spring components

Air Spring Construction

Coil-Rite springs are constructed of durable, elastic polyurethane to ensure years of service. Single replacement springs (sold separately) are available for maintenance to an existing Coil-Rite kit.

Air Spring Installation

The Coil-Rite springs install inside your existing coil springs. The custom-fit springs attach to your vehicle's spring seats.

W237604135 Firestone Coil Rite Air Bags - Suspension Kit - Rear Axle

Firestone 4135

Installation Details F4135 Installation instructions

Customer Satisfaction Score:

Customer Reviews

Firestone Coil-Rite Air Helper Springs - Rear Axle - F4135

Average Customer Rating:  4.4 out of 5 stars   (498 Customer Reviews)

For safety and stability, air springs are the perfect partner for your rear suspension when you are hauling heavy loads. Springs fit inside existing coil springs to help level your vehicle, improve braking and handling, and reduce tire wear.

2016 Toyota4Runner

Installed on a 2016 4Runner in conjunction with a 1-1/2" Daystar coil spring spacer. Since the coil spacer is hollow, I left one segment of the factory bump stop in place to compensate for and match the height of the spacer. I also added a Firestone T-fitting on the airline for a single inflation point and located the inflation valve next to my trailer plug wiring. Quite a pain to wrestle the coil back in place with the added height of the spacer, but that is no fault of the airbags; pry bar proved critical to wedge the coil back in place since I did not try the bottle jack between the frame and axle trick. After nearly a year, no leaks, bags hold air well. I put 25 psi in them for towing our travel trailer, or keep them at 10 psi for normal running around. I have also found them useful to prevent or at least reduce bottoming out the soft rear suspension that happens when off road driving with even just a couple hundred pounds in the back. Even at 25 psi they ride great and you wouldn't know they are back there at 10 psi. Highly recommend for the low cost and added versatility!

Still working great after a year. Knock on wood... no leaks to date. I would consider these essential equipment for towing, and would highly recommend for heavily loaded backcountry travels as well. I did try them near their max pressure on one trip with 5 people, roof top tent, and gear for a week of camping this summer and it was too much and felt very unsafe ped the pressure back to sub-30 psi after driving a few blocks and all was great after that!
Off2Mtns - 12/14/2018

2014 Toyota FJ Cruiser

Install was easy on 2014 FJ Cruiser...pulled the wheels off, jacked it up a bit, and the axle dropped enough to allow room to fit the bags inside the springs. I will see how they perform when I hook up my trailer but they inflate quickly and I can see these will stop my vehicle from squatting when the cargo area and trailer are heavily loaded. Another excellent product offered by etrailer...thanks.

After a year of regular use, these bags have been great. They keep my FJ level when towing and as a result steering while towing is vastly better.
Ryan G - 05/23/2018


Best $xx.xx I’ve yet spent on trailer towing. They are so great for leveling off vehicle when towing. And they adjust easily for different trailers/tongue weights. Make a “load” of difference and way cheaper / easier than a weight distribution hitch. I installed these myself on a 4Runner, in my garage with two jack stands and a floor jack. Video was great and everything went just as shown in the video. Only difference was that my vehicle has KDSS suspension. Need to tie kdss rod cylinders with zip ties to hold same length when bottom bolts disconnected. Keeps it from needing rebalancing.

2017 Toyota4Runner

Just installed the Firestone air bag system in my 2017 4Runner. After installing a 250lb aftermarket bumper the sag to the springs was just too much, I also tow a watercraft trailer so that would squash the springs even more, the simple solution is the Firestone air bag system. Install was easy. With my spare permamently out of the undercarriage I just used two existing holes to mount the valves. I think for what you get the price is a bit much, but you can look at it like the air bags will provide a service for hopefully years to come, so that is worth the price.

2013 Toyota4Runner

First try at installation did not go well. Put everything up and tried again next day after watching a few online videos. Much better success. Main thing was the instructions did not mention taking the rear wheels off. Once I did that, everything went more smoothly.

2021 Toyota4Runner

Quick process great packaging and everything was it good shape

2019 Toyota4Runner

I use them on 5th gen Toyota 4Runner while towing my 19 ft trailer. I inflate them to 30 pounds and my truck is almost perfectly horizontal. No need for the weight distribution hitch which by the way is not recommended on my truck.


The air bags do a great job of helping to level out the load. The ride seems better as well. Air bags Are not a replacement for a load leveling hitch and should not be treated as such. They can and do complement a load leveling hitch though.

2014 Toyota4Runner

Works well. Does not leak once installed. Correctly. Is a bit tricky to get hoses cut exactly at 90 degrees (to avoid leaks). On 5th gen 4runner you can just jack up car and install air bags upside down (nipple down). No need to undo axle/shock.

Still working a year later.
wraymond p - 08/31/2018

1999 Toyota4Runner

I purchased this product to prevent rear suspension sag in my '99 4Runner while loaded with camping gear and towing a small boat. It's surprisingly easy to install, and it works very well! I'm very pleased with the purchase. And, as always, the customer service at etrailer was second to none! Shipping was fast, pricing was competitive, and the product was exactly as advertised. Thanks to the folks at etrailer!


etrailer’s website is one of the easiest and best websites to navigate and place an order! They have lots of pictures and how to videos on almost every product I looked at which is super helpful. Their order process was simple. Their order shipping details was very well put together and made it super simple to track my order.

I am extremely impressed with their customer service! We will order everything we may need from this website from here on out!

2019 Toyota4Runner

Super easy install didn't even have to take anything apart, just squeeze the bags between the springs. Thank you so much to e-trailer! You guys had this on the shelf and shipped out right away got here early thank you! My only complaint is that your overpriced, but you had it on the shelf so I guess I shouldn't complain. I'm giving you 5 Stars because you are one of few vendors I have dealt with that I had 0 problems with. Worth the expense.


Works well easy to install


Not too hard to install between the springs with the rear-end lifted. Currently one side can’t hold more than 35psi probably because of tubing not fully inserted in bag. Will have to lift rear-rear end to investigate...

2016 Toyota4Runner

Helps keep our 2016 4Runner level when towing our 3,500 lb travel trailer. Easy to install, very reliable, fill with air using a bike pump. Super simple! Highly recommend.


Easy to install and works as advertised. Keeps the truck level when pulling a trailer with just 10 psi in the device.

Still works well, no issues. Its been a good investment .
Andrew - 03/06/2020


Just installed on a 2020 4runner. Wasn’t as hard as anticipated. I’d suggest using windex and lube the bag up when installing and look up video tutorials on [online] for help. No special tools needed. Haven’t tested it yet but so far so good.


Product was competetively priced well packaged and delivered fast.

2018 BMW X2

Extremely Easy install!

2015 Toyota4Runner

Etrailer is our go to for all our trailer accessories. Parts are always delivered on time and they provide quality parts at a great price.

2015 Toyota4Runner

Items were missing from the package. I called the manufacturer and they were less than helpful. I purchased this brand partly because of the Lifetime Warranty, however I'm now less than confident that I will have any luck actually filing a claim should any issue arise. If I were to make this purchase again I would go with the competitor's product.

2016 Toyota4Runner

Product was in stock and shipped quickly, as usual!


Working great a year after installation. No issues at all.
Mark - 02/07/2022

2016 Toyota4Runner

Having the ability to input vehicle year, make, and model really helps in getting specific product. Very easy to do. Price checked product online with several other websites and it was equal or withing a couple bucks. Free shipping was a plus and excellent packing.


Show More Reviews

See what our Experts say about this Firestone Vehicle Suspension

  • Suspension Enhancement Recommendation for 1998 Toyota 4Runner
    In situations like yours you have to go by what the manufacturer of the vehicle states. They are who designed the vehicle and know what is safe to use with it. What you can use is suspension enhancement for the rear axle of your 1998 Toyota 4Runner like the Firestone kit part # F4135 which is a confirmed fit. This will help reduce the rear end sag you are experiencing when towing when you inflate the bags.
    view full answer...
  • Will Firestone Coil-Rite Air Helper Springs Work On 2009 Toyota FJ Cruiser With 3-Inch Lift
    I called my contact at Firestone about your 2009 FJ Cruiser with the three-inch lift. They told me if you have changed out the factory springs to a different spring that has a different diameter then they will need the inside diameter of the spring with the vehicle weight on the springs. This will tell them what size bag should be ordered with the # F4135 Ride-Rite kit. If you did not change out the coil springs then the # F4135 kit will work for your vehicle.
    view full answer...
  • Firestone Coil-Rite Air Helper Springs # F4135 Installation On 2016 Toyota 4Runner
    I reached out to my tech contact at Firestone, and he said that as long as there is no pinching or crimping of the air line, you can install the Firestone Coil-Rite Air Helper Springs rightside up or upside down. They will function the same as long as they have the lines running without interference.
    view full answer...
  • When Should Air Bag Style Suspension Enhancement Have Air Added to the Bags
    With air bag kit the best time to inflate them is after the vehicle is loaded. This allows you to inflate the bags to the needed pressure to allow the vehicle to sit as level as possible.
    view full answer...
  • Can Firestone Coil-Rite Air Helper Springs be Used on 2019 Toyota 4Runner With KDSS
    You can absolutely use the Firestone Coil-Rite Air Helper Springs # F4135 on your 2019 Toyota 4Runner with the Kinetic Dynamic Suspension System (KDSS). This dynamic system will not affect the helper springs because the springs are installed inside the coils of your 4Runner. There are no separate installation instructions for the KDSS version, which has been around for quite some time. I checked the instructions for other vehicles with this system as well as fits to ensure this. I recommend...
    view full answer...
  • Could Air Lift Coil Rite Kit for 2016 Toyota 4Runner Install without Removing Coil Spring
    If you are able to cut the jounce bumper of your 2016 Toyota 4Runner off while leaving the coil installed on the vehicle you certainly could fit the air bag between the coils to install the # F4135 since this is commonly how it's recommended bag kits like this get installed.
    view full answer...
  • How Can I Stop my Air Helper Springs From Leaking
    The most common issue with air bags like the Firestone Coil-Rite Air Helper Springs part # F4135 is the connection of the air line to the other components. It is recommended to use a spray bottle with soap water to spray each fitting to see which is leaking. Once you have found it remove the air line and re cut it. Make sure to get a very straight even cut. An angled or crooked cut will cause leaking every time. Then place it back in and retest.
    view full answer...
  • Will the Firestone Coil-Rite Air Helper Springs For a 2014 Toyota 4Runner Work With XREAS
    Yes, the Firestone Coil-Rite Air Helper Springs part # F4135 will fit a 2014 Toyota 4Runner with the XREAS Suspension. The XREAS Suspension does not affect the coil springs, just the shock abosrbers so there will be no fit issues.
    view full answer...
  • Suspension Enhancement Recommendation for 2020 Toyota 4Runner
    The best suspension enhancement solution we offer for your 2020 Toyota 4Runner is the Firestone kit part # F4135. This is an air bag kit that will allow you to add air pressure to the bags as needed to provide the support you're looking for. For a compressor kit then the heavy duty part # F2097 will make inflating the bags and maintaining them very easy. The compressor will inflate faster than standard compressors and the gauge inside the vehicle will allow you to monitor and inflate...
    view full answer...
  • Rear Suspension Enhancement Recommendation for 2020 Toyota 4Runner that Tows and Off-Roads
    I'd recommend an air bag kit solution for your 2020 Toyota 4Runner like the Firestone kit part # F4135 as it will give you the ability to adjust exactly how much support you'd need. The alternative solutions have a tendency to be a bit harsh when unloaded which would make for a pretty unpleasant ride quality when off-roading so that is why the Firestone air bag kit is superior. For a compressor kit then the heavy duty part # F2097 will make inflating the bags and maintaining them very...
    view full answer...
  • Best Air Springs For 2020 Toyota 4Runner With KDSS
    There are coil air springs (though not traditional air bags) that fit your 2020 Toyota 4Runner with KDSS, and the best of those is from Firestone due to their quality. The correct fit for your '20 4Runner is the following: - Firestone Coil-Rite Air Helper Springs - Rear Axle # F4135 The Coil-Rite Springs # F4135 install inside your 4Runner's coil springs, and when you inflate them your springs become more effective, cushioning the load to help level you out, improve stability, and reduce...
    view full answer...
    Image 1 for
  • Recommended Air Springs For A 2023 Toyota 4Runner
    Out of all the air bags we offer I recommend the Firestone Coil-Rite Air Helper Springs # F4135 for your 2023 Toyota 4Runner. I like the Firestone airbags over the other air bags we carry because they're more durable and are constructed better than the other airbags that we offer. The Firestone springs fit inside the existing coil springs which will help level your Toyota 4Runner. It will also help with improve braking and handling, and also help reduce tire ware. To make you life easier...
    view full answer...
  • Replacement Thermal Sleeve Protectors for Firestone Coil-Rite Air Helper Springs Air Lines
    For replacement black line protectors on the Firestone Coil-Rite Air Helper Springs # F4135 you can use the Replacement Thermal Sleeve # F2135820899. The Replacement Thermal Sleeve # F2135820899 states that it is for the Firestone Ride-Rite Air Spring Kits, but both the Ride-Rite and the Coil-Rite use 1/4" line. So the sleeve will also fit on the Coil-Rite air line.
    view full answer...
  • Recommended Suspension Enhancement System For 2004 Toyota 4Runner
    I recommend installing the Timbren system # TTORSEQ over the Firestone # F4135. Since you said you occasionally tow or carry a maximum of 3,000-lbs, the Timbren system would be a nice option because you do not have to make any adjustments to the system. As more weight is added to the vehicle either from tongue weight when towing or loading the back of the vehicle, the Timbrens will stiffen to provide more support for the load. Using the Firestone system means you will need to adjust...
    view full answer...
  • Suspension Enhancement Options for 2020 Toyota 4Runner
    We have two options for suspension enhancement for your 2020 Toyota 4Runner which have pros and cons. The air bag kits like the Firestone part # F4135 have the advantage of being very adjustable which allows you to have the suspension support when you want it and then have the full ride quality of your vehicle when not needed since you can deflate them. The disadvantage is that the install is a bit more involved and you have to maintain air pressure in the bags. This is better for someone...
    view full answer...
  • Best Suspension Enhancement Option for a 2016 Toyota 4Runner
    The best suspension enhancement system for a 2016 Toyota 4Runner will be between the Firestone Coil-Rite Air Helper Springs part # F4135 and the Timbren Rear Suspension Enhancement System part # TTORSEQ. I recommend the air bags as you can control the level of support/comfort that that you need. That said, if you just want a set and forget sort of deal then the jounce springs are an excellent option.
    view full answer...
  • Helper Spring Suspension Options for 2006 Toyota 4Runner
    Since you don't continually carry loads in your cargo area, I'd recommend the Timbren # TTORSEQ aeon springs. The Timbren springs don't have any effect on ride until the extra weight is added to the rear of your vehicle. As more weight is added, the springs will get stiffer. The springs will not increase the cargo capacity of your vehicle, but they will help level our your ride height when you're carrying the heavy equipment around. Air suspension systems like # F4135 are great, but unless...
    view full answer...
  • Suspension Enhancement Recommendation for 2020 Toyota 4Runner TRD
    There are two great options for suspension support that fit your 2020 Toyota 4Runner 4WD with the Timbren kit part # TTORSEQ or the Firestone Coil Rite part # F4135. They each have distinct advantages but I think you'll be happiest with the Firestone. Timbren kits are easiest to install and maintain as they basically install once and you never have to worry about them, but their drawback is that they have a tendency to make the unloaded ride quality rougher. So that's overall why I'd recommend...
    view full answer...
  • Will the Firestone Coil-Rite Air Helper Springs # F4135 Fit a 2015 Toyota 4Runner with 2 inch Lift
    Since you have a 2 inch lift on your 2015 Toyota 4Runner you will need to do adjust the Firestone Coil-Rite Air Helper Springs # F4135 to accommodate the 2 extra inches. You can try cutting the bump stops so that they are 2 inches longer than what the installation instructions call for, but that has not been tested so you wouldn't necessarily know what the weight capacity rating would be. I spoke with my contact at Firestone and he said that he doesn't have any airbags that are fit the...
    view full answer...
  • How to Remove Air Line From Spring of Firestone # F4135 Coil-Rite Air Helper Springs on 2001 4Runner
    In order to remove the air line from the push connector on the coil air bags, you'll need to use a pair of needle nose pliers and grab the collar on the connector. If you push the collar toward the air bag and pull on the air line at the same time, the line will easily come out of the connector. If you'll be cutting the air lines, Firestone recommends using an air line cutter like # AL10530 to guarantee a clean cut. If the cut is rough, or isn't perfectly perpendicular, the connection...
    view full answer...
    Image 1 for
  • Union T Recommendation for Air Bag Setup for 2012 Toyota 4Runner
    For simplicity sake you would be better off using a T-union so that you only have to inflate one thing and wouldn't have to worry about equalizing the pressure. For a union all you need is the part # AL21838.
    view full answer...
  • Air Spring Compatible with 2016 Toyota 4Runner TRD Pro
    The Firestone Coil-Rite Air Helper Springs - Rear Axle # F4135 are currently the only air spring fit for your 2016 Toyota 4Runner. I've attached the installation video to assist. If you want to add the compressor so you can adjust the pressure for your desired ride comfort, I recommend the Air Lift WirelessONE Compressor System for Air Helper Springs - Remote - Bluetooth - Single Path # AL25980.
    view full answer...
  • Recommended Air Springs for 2018 Toyota 4Runner TRD Off Road
    The Firestone Coil-Rite Air Helper Springs - Rear Axle # F4135 is the correct fit for your 2018 Toyota 4Runner TRD Off Road. Air Lift brand doesn't have a confirmed fit at this time for your vehicle, so I recommend using the Firestone brand. This air spring will fit inside the coil springs to provide additional support. If you want to utilize a compressor system to adjust the air in your springs I recommend using the Air Lift Air Shock Controller Compressor System for Air Shock Absorbers...
    view full answer...
  • Recommended Suspension Enhancement for a 2006 4Runner V8 with Suspension Lift Kit
    The Firestone Coil-Rite Air Helper Springs # F4135 are designed to be used with stock suspension, so it will not fit an aftermarket suspension lift kit, unfortunately. This will also be the same for the Air Lift 1000 Air Helper Springs # AL60809. To install one of the suspension enhancement systems we currently carry for your 2006 Toyota 4Runner, you will need to have the lift kit removed and the stock system reinstalled.
    view full answer...

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