1. Vehicle Suspension
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Firestone Coil-Rite Air Helper Springs - Rear Axle

Firestone Coil-Rite Air Helper Springs - Rear Axle

Item # F4138
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Firestone Light Duty Vehicle Suspension - F4138
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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. Lowest Prices for the best vehicle suspension from Firestone. Firestone Coil-Rite Air Helper Springs - Rear Axle part number F4138 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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Firestone Vehicle Suspension - F4138

  • Firestone
  • Air Springs
  • Rear Axle Suspension Enhancement
  • 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 vehicle, improve braking and handling, and reduce tire wear.


Features:

  • 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


Specs:

  • 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.



W237604138 Firestone Coil Rite Air Bags - Rear Axle

Installation Details F4138 Installation instructions

This Product Fits The Following Vehicles





Customer Reviews

Firestone Coil-Rite Air Helper Springs - Rear Axle - F4138

Average Customer Rating:  4.4 out of 5 stars   (243 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.

- F4138
by:
2015 Honda Odyssey

I have a 2003 Acura MDX with 197k miles on it. I have used it for towing a 6x12 trailer for 3 quads. I have also towed many loads of dirt, mulch you name it. The rear sags allot and I just bought a 19' boat. I found this kit on etrailer and ordered it. The box came and it said it was for a Honda Odyssey. I double checked online with various sites and confirmed that all Acura MDX, Honda Pilot, Honda Odyssey, & Honda Ridgeline all have the same coil spring suspension with bumper stops inside the coil. I found a great forum which included pics of someone else that installed similar kit. I used those as references to install mine. Here are the steps to install which took about 2 hours: 1) Jackup car, and suppored with good jack stands 2) Removed tires 3) Using a 7/8" hole saw and made a hole in the middle of the lower control arm. 4) Filed the burrs 5) Installed a 7/8" grommet (not included in kit, I got this a local ACE hardware store) 6) Removed bolt from lower control arm knuckle to lower the arm. 7) The bolt for the bumper stop is not accessible, so I used a hand saw and cut about 2" of the rubber stop out. 8) Compressed the air bag and installed the plug (supplied) to keep it compressed, inserted the airbag thru the coil. 9) I deviated from the instructions which says to use the included plate at the top of the airbag which requires removing the bumperstop. Instead I placed this at the bottom of the airbag, which nicely has a grove in the middle which allows the connection for the airtube to sit in and keep it protected. 10) I routed the airline thru the factory openings in the lower control arm & rear end and up thru the trailer harness opening into the rear compartment in the trunk where the head rests go for the third row. 11) Reattached the lower control arm 12) Install tires 13) Lowered car 14) Inflated the bags to 15 psi which returned the truck to just a little above the stock height. I must say this is exactly what I was looking for. I towed the boat this weekend and didn't sag at all, the ride was much smoother then ever. Even with nothing attached to the truck, the ride is much better. My opinion is that this should be installed for anyone that uses the third row seat, or tows anything at all Acura MDX, Honda Pilot, Honda Odyssey, & Honda Ridgeline as it eliminates the typical rear sag! 146221



- F4138
by:

Most challenging to install. Not snap fit. Removal of several components and careful routing of delicate air line also had to purchase grommets for holes where chaffing of air line would occur. Don't expect longevity. Suggest development of a single support spring assembly to be better engineered and increase longevity, reliability, and ride stabilization as well as load capacity. Rusted parts don't disassemble with out heat and air tools. New bolts washers and nuts should be included. Thank you 265078



- F4138
by:
2014 Kia Sedona

Maybe excellent after I try to fix it. Seems the driver side wont hold air too long. I just need it when I pull my Casita camper with my KIA Sedona and I just add air before I start out. Not too annoying really. Fixing it may be a little more difficult then living with it. But I think it was a good idea to buy and install. 627708


Comments
The vast majority of the time, leaks will occur where the tubing enters the spring. If the tubing is not cut at a perfect 90° angle, its going to leak. You can test this by pressuring up the system and painting a solution of dishwashing liquid and water at the point where the tubing enters the fitting. If theres bubbles, theres your leak.
-- Mike L - 04/13/2019

52889

- F4138
by:

The instruction video showed exactly how to install these. Just disconnected rear lower suspension arms and drilled holes for the air lines. Swapped in the top plates for the air bags and put everything back together. They work great. We top them off every couple weeks, but really only necessary to top them off when we are going on trip or towing something. Hitch doesn’t scrape any more and body roll is reduced. Great investment. Highly recommend. 667173



- F4138
by:

Easy installation, has worked as advertised on my Kia Sedona van. I carry heavy equipment and inventory for my mobile embroidery business and it definitely helps with leveling and stabilizing the load. 746587



- F4138
by:
2016 Kia Sedona

Installed easily on my 2016 Sedona. I am pulling a pop up camper and this helped keep it level without adding stiffness to the van suspension. I only wish the tube didn't hang down below the suspension, 616519



- F4138
by:
Kia Sedona

Great product for Kia Sedona 2012 Towing my boat was heavy on car’s rear suspention. These airhelpers are great Easy to install 574073



- F4138
by:
2016 Kia Sedona

Love the product! Holds my Sedona level, even with all the kids plus a load in the rear. Evens out the ride driving over bumps. Great for towing a trailer. Only down side was installation. I had the product installed by the Kia dealer as I figured it would be easy for them; it took the professionals 4 hrs to install. Outside of the cost for installation, great value for the money. Highly recommend! 514351



- F4138
by:

So far so good, It's been installed for a month, carries the wheel chair with little or no dropping of the rear end. 439096



- F4138
by:

Firestone Coil-Rite still doing great. 363164



- F4138
by:

Have not installed it yet but I will follow up when it is installed. Great ordering experience and all was as described on website. 141733



- F4138
by:
2004 Honda Odyssey

Kit has made the ride in my Honda Odyssey overall better. Also keeps the back end from sagging to far when I've got the trailer on. Quality parts (stainless steel valves and valve caps) easy instructions and it fits perfect. Only drawback was that I had to have my mechanic install it, but after talking with him he said that it would have been a challenge without a lift. 90923



- F4124
by:

Review from a similar Coil-Rite in Vehicle Suspension


These air helper springs did exactly what we needed. We tow a Jayco Hummingbird trailer (3,750 lbs, 450-500 lb tongue weight) with our 2000 Toyota Landcruiser. Even with a weight distributing hitch the rear end squatted a bit more than I wanted. With the air helper springs installed rear end squat has been completely eliminated. Driving without the trailer feels more firm and connected to the road. The only negative is about the complexity of the installation. On the 2000 Landcruiser it requires that the rear suspension be partially disassembled. That was far more than I could handle at home. It took our neighborhood auto shop 3 hours to complete the job. Money well spent. 638942


Comments
It took some work by the shop, but it’s finally working as designed. The touting of the air hose from inside the coil spring is through an existing hole in the frame was binding and causing the driver side hose to become kinked. The shop had to enlarge the hole and one that was done there have been no more problems.
jmcdermo - 05/07/2020

75902

- F4170
by:

Review from a similar Coil-Rite in Vehicle Suspension


Product is what you see on the web page and the videos exclent its idiot prove 411973



- F4118
by:

Review from a similar Coil-Rite in Vehicle Suspension


Good product. takes some effort getting the bag inside the coils. As far as removing the frame bumper - didn't do it - it is pressed in between the frame and top of coil spring. So far so good 514375



- F4118
by:

Review from a similar Coil-Rite in Vehicle Suspension


I got the a draw tite hitch, wiring harness and Firestone coil helpers for my 2016 Nissan pathfinder. Everything fit great and was easy to install. The price was awesome and shipping was super fast. An easy A+ for etrailer.com. 343985



- F4105
by:

Review from a similar Coil-Rite in Vehicle Suspension


Did not work at all on my 11altima. No change to the suspension and the bags deformed beyond recognition after 2 weeks 260702



- F4118
by:

Review from a similar Coil-Rite in Vehicle Suspension


Easy installation fixed my problem of low ride height. The only thing I would change is I wish there was a 90° angle for the bottom so it doesn't stick so far out I know it's going to end up catching things on the road 595108



- F4174
by:

Review from a similar Coil-Rite in Vehicle Suspension


Working out very well 735132



- F4118
by:

Review from a similar Coil-Rite in Vehicle Suspension


I've installed the air springs and and they hold up great. I'm pulling a tall 5 x 10 enclosed trailer and no more sagging in the rear end. Air up the bags to 35 max PSI and the ride quality is excellent. 715974



- F4118
by:

Review from a similar Coil-Rite in Vehicle Suspension


We ordered a suspension kit it came right away and at a great price. We had checked out several shops in town who said they were hard to get for our new vehicle and the cost was out of this world. Great job guys 165779



- F4175
by:

Review from a similar Coil-Rite in Vehicle Suspension


Product installed without any issues. Do suggest taking a paper towel or rag and spraying a small amount of WD40 on it and wiping around spring coils only not on air bag. Bags slide in a little easier. Would have been 5 Star except for unacceptable shipping time, 5 days to on instate location 200 miles away. 579207



- F4174
by:

Review from a similar Coil-Rite in Vehicle Suspension


As a former mechanic, this was a tough install. It was a struggle to get the air bags through the springs and there was not enough room to remove the 3" piece of tubing so I installed the bag with the full length of tubing already in place. I was hoping to gain about a 2" lift, but it only raises the vehicle about 3/4 of an inch. The bags do make a noticeable difference in handling and the hitch is not so close to the ground while hauling a trailer. 103341



- F4176
by:

Review from a similar Coil-Rite in Vehicle Suspension


Used the Air Helper Springs on a VW Jetta to help when we put the 4 bike rack on it. Worked perfectly, kept us level when loaded and letting the air out gave us the ride when empty. Bike pump easily pumped them up when needed. I would recommend this product for anyone needing to control ride height under load or when towing to stiffen the suspension. We have had them installed for over a year. Way to go eTrailer! 240426


Comments
Continues to work well. Would recommend without reservation
Tim F - 03/09/2017

22663

- F4124
by:

Review from a similar Coil-Rite in Vehicle Suspension


Review is for very helpful service- got into a time squeeze, made a call on Sunday, and received the correct part on Tuesday AM. No review on product yet, but it looks like it should work well. The go into the rear coils of a Toyota Sequioa and are currently being installed. 662780


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Ask the Experts about this Firestone Vehicle Suspension

  • How to Get the Rear Spring off the Spring Perch on a 2010 Kia Sedona
    A long screw driver or pry bar should do that trick. I had a similar situation with my car and was able to pry the last bit of the spring off the perch by using a pry bar in one hand and a long slot screwdriver in the other. I pried up with the pry bar and then to the side with the screwdriver to help slide it off the perch. Be careful and take your time. To get it back on you will just need to reverse the process. Leverage is your friend, use the pry bar to compress the spring and the...
    view full answer...
  • Suspension Enhancement for 2016 Kia Sedona
    eTrailer.com does not manufacture air bags, but we do offer suspension enhancement air springs for your 2016 Kia Sedona. Firestone's Coil-Rite Airs Helper Springs, # F4138, are the only enhancement we currently offer that is a fit for your vehicle, but they are a custom fit. This system utilizes compressed air to partner with your vehicle's rear suspension. The air springs fit inside the metal coil springs already on your 2016 Kia Sedona to help with a number of issues, like sagging,...
    view full answer...
  • Installing Firestone Coil Rite Air Helper Springs # F4138 on 2010 Kia Sedona
    The Firestone Coil-Rite Air Helper Springs, part # F4138 will install so that they sit inside the coil springs of your suspension on your Sedona. To install the springs, the lower control arm will be unbolted from the knuckle, allowing it to drop free and the coil spring to be removed so that the air spring can be inserted. You can see the full installation instructions by clicking on the link I provided. When installing the springs, cutting the air line perfectly square is crucial...
    view full answer...
  • How to Check for Air Leaks on a Firestone Coil-Rite System with Inaccessible Inflation Valve
    That is an excellent point. Firestone was recently here for training and they did address the issues installers have had with the instructions. Basically they are going to be redesigning all the instructions. But for you, you can check for leaks at every other place that you can (without disassembling the vehicle). Assuming everywhere else checks out then if there is a leak the only remaining place it could be would be the one place you can't get to unless you pull that control arm back down.
    view full answer...
  • Installation of Firestone Coil-Rite Air Helper Springs Part # F4138 on 2007 Hyundai Entourage
    According to our friends at Firestone, drilling the hole in the control arm will not weaken or otherwise damage the vehicle. The hole is absolutely necessary to provide access for the air line to connect to the bottom of the Coil Rite air spring.
    view full answer...
  • Installing Firestone Coil-Rite Air helper Springs On 2000 Honda Odyssey
    Per the installation instructions for the Firestone Coil-Rite Air Helper Springs, part # F4138, the overload bumper inside the coil spring will need to be unbolted and removed. You will also need to drill a hole in the lower control arm when installing this system. I have attached the installation instructions for this system you can check out. Installing a system like the Firestone Air Springs will not increase the vehicle weight carrying capacity.
    view full answer...
  • Can a 2015 Kia Sedona Safely Tow a 3,700 Pound Jayco Travel Trailer
    What I recommend is a trailer that has a gross trailer weight that meets or is under the towing capacity of your 2015 Kia Sedona which is 3,500 pounds as long as the trailer has brakes. You can tow a trailer rated higher provided that the actual weight of the trailer does not exceed that 3,500 pound tow vehicle capacity. So they aren't lying about that but you do run the risk of overloading the tow vehicle by going with a heavier trailer. You will likely need suspension enhancement...
    view full answer...
  • What can I do to Level My 2008 Kia Sedona when Towing a Trailer
    What year is your Kia Sedona?
    view full answer...
  • Comparing the Reese Light Duty Weight Distribution System to the Pro Series RB2 for a 2700lb trailer
    When choosing a weight distribution system, the most important factor to consider is the fully loaded and ready to tow tongue weight of your trailer plus the weight of any cargo behind the rear axle of your 2004 Honda Odyssey. Tongue weight of a trailer is typically calculated to be 10 to 15 percent of the gross trailer weight. If your Scamp trailer weighs 2,700 lbs, then the tongue weight may be around 270 lbs to 405 lbs. You must then add the weight of the cargo that you load in the back...
    view full answer...
  • Suspension Enhancement Options for Towing With 2004 Acura MDX
    The Firestone # F4138 and # W237604138 are the same part. 4138 is the part number, and W237604138 is the SKU number that Firestone uses internally. Both the # F4138 and the Timbren # THROD2 are compatible with MDX models that have the coil spring rear suspensions only. It will not work on models equipped with the Coil-Over-Strut suspension. The Timbren springs will suspend up to 2000 lbs loaded in your MDX, while the Firestone Air Suspension is good for up to 1000 lbs. Neither system...
    view full answer...
  • Parts Needed to Safely Tow a Pop Up Camper with a 2016 Kia Sedona
    1. Normally I'd say that your 2016 Kia Sedona would be just fine as long as the pop up has brakes, but since your towing capacity without brakes is only 1,000 lbs it would be a good idea to install one. As far as the warranty is concerned you are protected by the Federal Magnuson-Moss Warranty Act. The Act states that if something breaks on your vehicle and you take it in for warranty repair, the dealer must honor your warranty unless whatever modifications you have added to your vehicle...
    view full answer...

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Info for this part was:

Updated by:
Leah B
Updated by:
Mary E
Updated by:
Sarah W
Updated by:
Alex H
Expert Research:
Mike L
Expert Research:
Jeffrey L
Written by:
Tyler C
Video Edited:
Joshua S
Video Edited:
Jacob T
Video Edited:
Chris R
Test Fit:
Nicholas E
Video by:
Alan C
Video by:
Jonathan Y
Installed by:
Robert C

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