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Vehicle Suspension > Rear Axle Suspension > Suspension Enhancement Kit > Jounce-Style Springs > Micro-cellular Urethane > Firestone

Firestone Work-Rite Custom Helper Springs Kit - Rear Axle

Firestone Vehicle Suspension

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Code:   F8620



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Shipping Weight: 12.9 pounds


Firestone Vehicle Suspension - F8620

Install these microcellular urethane springs above your rear axle to stabilize and support your vehicle's existing suspension. Unlike many one-spring-fits-all kits on the market, this one can be customized according to the weight of your cargo.


  • Improves suspension, handling and loaded ride comfort
    • Increases stability and minimizes sway from wind gusts or rough roads
    • Cuts down on road shock and provides a cushion to soften contact between axle and frame - helps to prevent bottoming out
    • Reduces suspension fatigue and spring sag
    • Does not affect your vehicle's ride when it has no load
  • Adjustable - offers spacers that allow you to customize for your typical load weight
    • Install more spacers to increase truck height and handle heavy loads; install fewer spacers for light loads
  • Made from injection-molded, microcellular urethane that has been engineered specifically for automotive applications
    • High resistance to repeated compression
      • Springs retain their shape longer
      • Less play is introduced into the suspension, giving you more control
    • Smooth axle-to-spring contact with urethane springs
    • Low temperature flexibility to -84 F (-63 C) helps springs work better in cold conditions
    • Effective resistance to road chemicals - extends life of springs
  • Requires no air-pressure monitoring as air springs do
  • Installs easily above your rear axle
    • No-drill design uses existing holes in the frame for installation in just 30 - 40 minutes
  • Saves money
    • Priced less than air suspension systems - enhanced support at lower cost
    • Protects your factory suspension from wear and tear - less maintenance required
  • Includes all parts needed for installation
    • 2 Load-assist springs
    • 1/2" Thick spacers for customizing support
    • Brackets and mounting hardware
  • Designed to work with a suspension system that is in good working order
  • Made in USA
  • 2 Year warranty on springs

Note: Firestone Work-Rite springs will not increase your vehicle's weight-carrying capacity. Do not exceed the manufacturer's weight limit for your vehicle.

Work-Rite springs reduce the rear sagging that accompanies heavy loads or that results from towing hefty trailers. Hauling heavy cargo or pulling a trailer often causes the rear of your vehicle to sag while the front end rises. This means that the rear axle is handling the full weight of the load and more of your truck's weight as well. The lighter weight on the front axle means that the front tires make less contact with the road, causing problems with traction, steering and braking. With the springs helping to more evenly distribute the weight, your tires make better contact with the road and your driving control improves greatly.

One size does not fit all when it comes to the load you carry. This spring kit lets you choose from different spacer combinations during installation to give you customized load support for the weight of the cargo that you typically haul. Using the optional spacers, you can adjust the distance between your springs and axle. Closing the gap between the springs and your axle offers more immediate support and better maneuverability because the Work-Rite springs respond sooner to the load's weight than springs without spacers.

Diagram showing how much space to leave between WorkRite springs and axleDiagram showing how much space to leave between WorkRite springs and axle

Use more spacers to close the gap if you usually haul heavy loads, engaging the Work-Rite springs sooner and increasing the height and improving the handling of your vehicle when it's loaded. Use fewer spacers if your loads are light or if you frequently travel unloaded. Leaving at least a 1/4-inch gap between the springs and your axle allows the existing leaf springs to operate normally when you're unloaded, ensuring a smooth, comfortable ride.

Each helper spring in the kit works independently to support the passenger's or driver's side of your truck so that when you swerve or turn sharply, the spring compensates to reduce body roll. Because your vehicle handles better with the springs, less turbulence is passed along to the trailer, helping to keep the trailer in line.

Your driving comfort is further enhanced if the trailer does begin to sway (for example, from a gust of wind or a passing big rig) because the movement from the trailer is not transferred to your vehicle. The helper springs also work to make the sway subside more quickly.

Work-Rite Springs Versus the Competition

Work-Rite springs are made of a special polymer that helps them to retain their shape better than rubber and still work in below-freezing conditions. They are less elastic than rubber, meaning less play is introduced into the suspension than with rubber springs. The firmer Work-Rite springs also resist road chemicals and extreme temperatures better than rubber, so they last longer.

F8620 Firestone Work Right Helper Springs Kit - Rear Axle

Video of Firestone Work-Rite Custom Helper Springs Kit - Rear Axle

Videos are provided as a guide only. Refer to manufacturer
installation instructions and specs for complete information.

Video Firestone Load Assist Install 2009 Dodge Ram 1500
Firestone Work-Rite Load Assist Installation - 2009 Dodge Ram 1500

Video Transcript for Firestone Work-Rite Load Assist Installation - 2009 Dodge Ram 1500

Today on this 2009 Dodge Ram 1500 we are going to install part number F8620 from Firestone. This is their Work-Rite Load Assist. To give you an idea of what is going on the new Firestone part actually replaces the factory bump stop right here. When you have the truck fully loaded, the only way it is going to stop is when it hits this bump stop and goes down to the axle. You can see we have got quite a bit of difference so if we put a load in the back of the truck or bounce up and down the road you can see how much travel this has. 00:28

With the new part installed it will take up that extra space and the vehicle will not sag as much on your load. The first step involved is to get the truck in the air we are going to use a standard jack stand to hold everything up. And we need to remove the rear tire. This is the factory bump stop right here, a better view of it. Basically we just have to remove it. You can pry it out or some cases maybe you can pull it out on your own. The truck is already prepped, lets go back to the kit and do some preassembly there. We have the parts assembled here for one side of the system. 01:06

We will cover the parts real quick. Obviously this is the new spring constructed of polyurethane material and then we have the brackets that hold everything together. You have this round plate which fits on top of the spring and then you have this ring that sits on top of that and then you have these two pieces that clamp over the existing bump stop on the vehicle so when you bolt it all together it clamps everything together. A couple of options, when you set it up you have a choice of using a couple of different spacers. Basically what this does is allows you to adjust the spring up and down. Say for instance the carpeting right here is the bump stop on the truck. You want to leave about 1/ 4 inch of space in between the two so it will give you a lot of space in here. You can lower it to take up the gap. Also if you want the springs to work sooner like in the truck you use in a constant loaded condition you probably want to add the spacers to have it already working right off the bat. 02:00

You get two different sized spacers to do that with. If by chance you did want to add spacers later which you can, undo the bolts, take it apart, add the spacers, reassemble, and then reinstall on the truck. Start with the spring. Since we are not going to use the spacers we are going to use the short bolt. If we did we would use this long bolt. Take the short bolt and the flat washer and install it where it comes out the end right here. It is a good idea to use a socket and extension and install the plate. You can see how the bolt holes are sunk in, that is because the bolts get installed like this so you want to have the plate mounted like this where the studs are pointing up. We will add our lock nut to it and just simply tighten it down at this point. Torque these down as specified in the instructions. We will do some more preassembly. Put the ring, center it to keep it from moving around and then take the clamp and do one side and run the bolt through and loosely install the flange nut. Take the middle one and run it down about half way so we still have some flexible room but it will hold it in place while I deal with the other side. 03:20

Lets go over to the truck and start assembling. We will slip it into place. As you can see here the clamp will fit over the edge and that will help hold everything in place while we install the other side. You can see how it is working on there right now so just snug down the bolts. Once you have everything snugged down go all the way around evenly and tighten them up as specified in the instructions. We have got our work rite installed so lets reinstall the back wheel and see what we have got. Once you have it installed you want to double check to make sure you have about 1/ 4 inch of space in between and not much more than that. If it is barely touching it will be fine also. Again if you need to adjust the height you can use the spacers in between the spring and the plate. Now we have got everything reassembled. You want to take it for a test run unloaded like it is now and then you may want to take a test run with it fully loaded. You may want to add a spacer or a spacer depending on how you originally installed it. There you have it for part number F8620 from Firestone.

This Product Fits The Following Vehicles

2012 - 2012 Dodge CV

2012 - 2012 Ram CV

2009 - 2013 Dodge Ram Pickup 1500, Crew and Quad Cab

2009 - 2013 Dodge Ram Pickup 1500, Regular Cab

2010 - 2013 Ram 1500 Crew and Quad Cab

2010 - 2013 Ram 1500 Regular Cab

Replacement parts available for this product

Customer Reviews

Firestone Work-Rite Custom Helper Springs Kit - Rear Axle - F8620

Average Customer Rating:  ratingratingratingratingrating4.7 out of 5 stars   (3 Customer Reviews)

- F8620

ratingratingratingratingrating by: anthony03/05/2013

Is this review helpful?

shipping was fast and instlation was a snap68986

- F8620

ratingratingratingratingrating by: Tom K.08/30/2012

Is this review helpful?

The product was exactly what I expected and was delivered in just 2 days......Great Service!53563

- F8620

ratingratingratingratingrating by: WADE WILLSON11/29/2012

Is this review helpful?

So simple I dont see any problems. Thank You60268

Ask the Experts about this Firestone Vehicle Suspension
Expert Answers about Firestone Work-Rite Custom Helper Springs Kit - Rear Axle - F8620                                             Do you have a question about this Vehicle Suspension?

  • Will Firestone Work-Rite Helper Springs Reduce Sag on a Chevy Silverado 2500HD Diesel
  • The Firestone Woirk-Rite springs will help with the sag at the back of your truck. However, # F8620, is designed for Dodge vehicles and will not fit your Silverado. I would need to know the year of your truck and if it is 4-wheel drive or 2-wheel drive to make a recommendation. Air bags should not cause any sway issues. However air bags would not be my first choice for this application since they are better for leveling a bed side to side for trucks that carry varying load sizes and types.
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Info for this part was:

Written by:
Tyler C

Expert Research:
Michael H

Written by:
Tricia G

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