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  1. Vehicle Suspension
  2. Pacbrake
  3. Air Springs
  4. Towing/Load Leveling
  5. Rear Axle Suspension Enhancement
  6. Heavy Duty
THIS ITEM IS NOT A FIT FOR
2027 Subaru Forester
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Pacbrake

Pacbrake Alpha HD Air Bag Suspension Kit - Rear Axle - 5,000 lbs

Part Number: PB56SV
In Stock
$543.53
Vehicle Suspension
Not Confirmed to Fit

2027 Subaru Forester

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5,000-lb Capacity. When the load gets heavy, your truck shouldn't feel like it's fighting you. These air bags help you stay level and in control so you can tow with confidence and handle heavy loads without second-guessing your suspension. Great Prices for the best vehicle suspension from Pacbrake. Pacbrake Alpha HD Air Bag Suspension Kit - Rear Axle - 5,000 lbs part number PB56SV can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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  • Reviews (57)
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Pacbrake Vehicle Suspension - PB56SV

  • Air Springs
  • Towing/Load Leveling
  • Rear Axle Suspension Enhancement
  • Pacbrake
  • Heavy Duty
  • Suspension Only

5,000-lb Capacity. When the load gets heavy, your truck shouldn't feel like it's fighting you. These air bags help you stay level and in control so you can tow with confidence and handle heavy loads without second-guessing your suspension.


Highlights

  • Custom Fit for Your Vehicle: Precision brackets bolt to factory attachment points - includes 2" spacer to maintain stance.
  • 5,000-lb Load Support: Adds rear axle support for towing, hauling, and bed-loaded stability.
  • Improved Ride Stability: Reduces rear-end sag, sway, and bounce for better handling under load.
  • Adjustable Air Pressure: Set support between 5 psi and 100 psi depending on your load.
  • Complete Kit, No Drilling: Includes laser-cut brackets, push-to-connect fittings, and all hardware.
  • Ready Now, Upgrade Later: Use manual inflation or connect to an onboard air system when you're ready.

Features to know about

Control and Cushion When It Counts

When the load gets heavy, your truck needs more than just rear springs hanging on for dear life. Alpha HD air springs add up to 5,000 lbs of rear axle support, keeping your truck steady even when the trailer is loaded, the bed is packed, and the miles are long. No more rear-end sag throwing off your braking and steering, or headlights pointing into the sky. With air bag support underneath, you keep control of your ride even when you're towing a travel trailer or moving a serious payload.

Dial in the Ride for Any Load

Every load is different, and this system adjusts to match. Alpha HD air springs let you fine-tune ride height and firmness with air pressure from 5 to 100 psi. When carrying heavy weight, add air to level your suspension and maintain steady handling. Running without a load? Drop to the minimum pressure for a smoother, more compliant ride without stiffness or bounce. Manual inflation valves are included, so tuning your setup for each trip is straightforward and dependable.

Built Tough for Work and Weather

Air bags are only as strong as their weakest link. That's why Alpha HD bags are reinforced from end to end with heavy-duty end caps, 20 internal support wires, and powder-coated steel brackets. Add corrosion-resistant hardware and thick roll plates, and you've got gear that holds up to real-world hauling through heat, cold, salt, and slop.

Installation That Doesn't Waste Your Weekend

Adding serious load support shouldn't mean losing a whole weekend. The precision laser-cut brackets are designed to bolt cleanly to your truck's existing mounting points with minimal drilling. Just smart engineering that fits the way it should, which is perfect for the DIYer. Manual valves mount through license plate fastener holes or a location of your choosing (which may require drilling). With high-quality fittings, pre-bent brackets, and mounting hardware included, you'll be back on the road in just a few hours without a trip to the fab shop.

Flexible for Today, Ready for What's Next

This kit is designed to work with your setup today and wherever your upgrades take you tomorrow. You can inflate manually with standard air valves right out of the box, no extra parts needed. Already have an onboard compressor? The Alpha HD system connects easily to most existing setups. Planning for an in-cab wireless controller down the road? No problem. The foundation is already built in, making it easy to expand your control options when you're ready.

Specs:

Weight & Capacity:

  • Load support: up to 5,000 lbs of additional leveling support
  • Air springs will not increase your vehicle's weight-carrying capacity. Do not exceed the manufacturer's recommended weight limit.

Adjustability:

  • Air pressure range: 5 psi 100 psi; maintain minimum 5 psi when unloaded

Estimated Install Time:

  • Professional install: 2 hrs
  • DIY: 3 hrs, depending on tools and experience. Plan for extra time if this is your first air spring install or you're working in a driveway setup.

Warranty:

  • Limited lifetime on air bags
  • 2-Year or 24,000 miles on mounting brackets, fasteners, and spacers

Included Components:

  • Pacbrake Alpha HD air springs (rear axle)
  • Precision laser-cut powder-coated steel brackets
  • Pacbrake 2" spacer
  • Grade 5 plated hardware
  • Air lines, push-to-connect fittings, inflation valves, installation instructions


HP10152 Packbrake Alpha HD Air Suspension Spacer for Single & Double Convoluted Spring Kits - 2"

HP10585 Pacbrake Alpha HD Air Bag Suspension Kit - Rear Axle - 5,000 lbs

Installation Details PB56SV Installation instructionsAlternate Instructions PB56SV Installation instructions

This Product Fits The Following Vehicles




Customer Satisfaction Score:

Ratings & Reviews

4.7

57 reviews
Review sort icon
5,000-lb Capacity. When the load gets heavy, your truck shouldn't feel like it's fighting you. These air bags help you stay level and in control so you can tow with confidence and handle heavy loads without second-guessing your suspension.

by:

Easy instal and has worked perfectly.



by:

nick was very helpful everything was as expected



by:

The product is a great product. After installation was completed and the air added to the air suspension, it raised the rear end of the van about 2-3 inches.A very nice improvement.
Installation instructions definitely need better quality diagrams.



by:

Easy to install and work just as I had expected. Great finish on brackets and quality hardware. Easy to follow instructions. Highly recommend these airbags!



by:

Looks great. Thanks



by:

Very well built brackets, installation was as explained in the instruction. Happy Camper!



by:

I put them to use today and was very happy with the ride and stability while towing my camper.



by:

Love the product
The directions could’ve
been a little more detailed



by:

Put about 1800 miles on these last weekend. Was picking up a car that's heavier than my normal race car on the ramp truck, so I wanted to give the truck a bit of help. Good news, it worked well. Truck rode beautifully, loaded or unloaded.

The instructions could be a bit more clear, in regards to the clinch stud. I had that on backwards at first because of how things appeared in the picture. Also, I know most things are DIY but installation was about 80% assembly, 20% actual install. If these came already assembled, it would have saved a lot of time!



by:

These fit absolutely perfect. Easy install help keep my truck level when connected to my fifth wheel.



by:

Simple to install, did it without pulling the tires and wheels I seen no need for that, It took me a total of 3 hrs. to install in my driveway.



by:

What a difference the air bags make when towing a camper. Installation was easy, instructions were well written.



by:

The air bags were very simple to install but the u bolts for my gooseneck mount interfered with the air bag mounting



by:

Good quality product. For my 2018 1500 Silverado it was a little difficult to get the U bolt over the frame but under the hard lines running on top of the frame in that area.



by:

Aluminum ends, brackets, and even packaging was all exceptional and part of the reason I choose these. Haven't trailered anything yet but upon initial install no noticeable difference ride difference running 10 psi on a F250.



by:

Worked well when pulling trailer. Kept vehicle and trailer level. Without trailer seems to creak and groan more than I thought it would.



by:

Both of the fitting leak where they swivel. Had to take everything back off. Not my first time installing bags but First time with this brand and will be the last. Etrailer won’t make it right and having me go though pacbrake. Waiting on email to get process started. They Don’t seem to be in any hurry. Will try and source fitting local so I can get this back together. Shane on you etrailer. I ordered from you and shipping was slow not knowing it was directly coming from manufacturer.



by:

Went in easy enough, better than I thought. Ride without trailer attached is good. Have not hooked up trailer yet



by:

Easy to install with the rear tires off, did one side at the time with a single jack and two jack stands. The towing of our fifth wheel is much better, much less chucking and more directional stable.



by:

I like these bags. This is my 3rd set of air bags but my 1st set of PACBRAKE I have owned and they are the best. Metal where others are plastic. Powder coated instead of paint that rusts off. nice hardware instead of crummy allan bolts that can't easily be removed. The bracing is much better too. They are by far higher quality than the firestone. Installation is about the same but they use stainless air fittings instead of plastic like the other guys. The ends of the PACBRAKE are machined aluminum. My Airlifts brand were plastic with inserts that broke out.(see pic) I havent had the chance to use the new PACBRAKE under tough conditions but the hardware and Materials they are made of are superior to the other brands.



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by:

They need instructions to be more clear but fit very nicely i would recommend pacebrake

Gwendolyn Y. profile picture
Etrailer Expert

Gwendolyn Y.

6/18/2025

Hey Jay. I'm sorry to hear that the instructs wasn't as clear as they should have been. Would you be able to share where in the instructions could have used a bit more clarification? I'd be happy to forward your feedback to the manufacture. I'm glad that everything fit nicely though!

Jay profile picture

Jay

6/18/2025

@GwendolynY its when pit them together and the holes are offset from passenger side and passenger side it said mirror for driver. I don't understand that term when its.the same thing but after thinking about it it isn't that bad sorry.
Gwendolyn Y. profile picture
Etrailer Expert

Gwendolyn Y.

6/18/2025

@Jay No worries at all, Jay! I can totally understand how that wording could be confusing. Are you going to be towing a trailer or hauling a load in the truck bed?
Jay profile picture

Jay

6/18/2025

@GwendolynY Towing i have 5 th wheels we Towing quite often
See All (4) Replies to Gwendolyn Y. ∨


by:

Installed this past weekend. Haven't towed with it yet. Nice construction and finish. I have a 2025 Chevrolet Trail Boss 2500HD and the spacers are NOT needed. Measurement for needing the spacers in 7" and above between jounce cup and contact pad. My space was 5.5" to 6".



by:

The 2" spacers are definitely not needed for a Trail Boss. I could barely get them in, and now the ride is super stiff. Now I have to get back under the truck and remove the spacers. Not looking forward to that. It was very difficult installation, for no reason.


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See what our Experts say about this Pacbrake Vehicle Suspension

  • Suspension Enhancement Kit Recommendation for 2025 Chevy Silverado 3500 Trail Boss
    Hey John, I do have a suspension enhancement kit that fits your 2025 Chevy Silverado 3500 with the PacBrake kit part # PB56SV but the Timbren kit and everything else we have that is listed for your truck does not fit the Trail Boss models. Would you be okay with an air bag kit?
    view full answer...
  • Availability of RoadActive Suspension Kit for 2025 Silverado 2500 Trail Boss
    Hey Wayne! I'm sorry to say that none of the RoadActive Suspension kits will fit the Trail Boss model. The same is true for almost every other suspension enhancement option. If you want extra support you can use the Pacbrake Alpha HD Air Bag Suspension Kit # PB56SV or # PB36SV (with jounce bumpers). These air bags are specifically designed to be compatible with the Trail Boss. I would choose the air bags with the jounce bumpers. This gives you extra support and protection from bottoming...
    view full answer...
  • Difference Between Pacbrake Air Bag Kits for a 2025 Chevy Silverado 2500 Trail Boss
    Hey Ken! The Pacbrake Alpha HD Pro Air Bag # PB36SV you're looking at has internal jounce bumpers while the Kit # PB56SV you're comparing it to doesn't. Internal jounce bumpers help to ensure your Trail Boss won't bottom out (metal on metal) if there ever is a time that the air bags fail. I know it seems like Pacbrake isn't as confident in their air bags if they have this feature built-in, but it's more like an insurance policy than anything. What's the main purpose of using the air...
    view full answer...
  • Can I Install the Pacbrake Alpha HD Air Bag Suspension Kit PB56SV On My Own?
    Seeing as how you'd be installing the Pacbrake Alpha HD Air Bag Suspension Kit item # PB56SV on a newer 2024 - 2026 Sierra or Silverado 2500/3500, I strongly recommend taking it somewhere if you're inexperienced. We do have a network of installers that can help you though. If you go to the product page of the Pacbrake item # PB56SV you referenced and scroll down below the pics on the left side you'll see a box that says, SCHEDULE AN INSTALLATION. Go ahead and click on it and it will take...
    view full answer...
  • Air Bags for 2025 GMC 2500 AT4
    Hey Charles! What kind of 5th wheel do you have? For your 2025 GMC 2500 AT4 I recommend the Pacbrake Alpha HD Air Bag Suspension Kit # PB56SV. These are high quality air bags (like Firestone) and this particular kit comes with the 2" spacer for AT4 models. The 5,000 lb load leveling capacity should be more than enough for your 5th wheel and they also feature a limited lifetime warranty. I also recommend adding an air compressor like the Pacbrake Single Channel Wireless Air Spring Controls...
    view full answer...
  • Will Pacbrake Alpha HD Fit 2025 GMC Sierra 2500 With B&W Turnoverball
    Hey Reed! Yes, the Pacbrake Alpha HD Air Bag Suspension Kit # PB56SV will fit your 2025 Sierra 2500 with the Turnoverball. The only 5th wheel/gooseneck exception for fitment with this kit is if you have a Curt 5th wheel so that doesn't impact you. I also highly recommend adding an air compressor like the Pacbrake Single Channel Wireless Air Spring Controls w/ Compressor and Remote # PB89MV. This will allow you to control the pressure in the air bags no matter where you go from the cab...
    view full answer...
  • Suspension Enhancement Recommendation for 2025 Chevy Silverado Trail Boss
    Hey Brian, we can help but there isn't a Timbren kit that fits the Trail Boss version of your 2025 Chevy Silverado Trail Boss. Instead we have the Pacbrake Alpha HD Air Bag kit part # PB56SV which was intended to fit the Trail Boss models so it is your best option. Unlike Timbrens with air bags you can tailor exactly how much suspension support you want from them by changing air pressure so you can get as much or as little support as you want at any given moment. Plus the Timbrens are known...
    view full answer...
  • Air Bags for 2026 Chevy Silverado 3500 Trail Boss
    Hey Josh, congratulations on the new truck! I would recommend Firestone but unfortunately, they aren't a fit for Trail Boss models. The next best thing is going to be the Pacbrake Alpha HD Air Bag Suspension Kit # PB56SV. This kit is specifically designed to fit your 2026 Silverado 3500 Trail Boss. Do you want an air compressor as well? The Air Lift WirelessONE Compressor System for Air Helper Springs # AL25980 will work with this setup. This is a single path system so the air pressure...
    view full answer...
  • Which PacBrake Alpha HD Kit Fits 2024 GMC 2500 AT4
    Hey KC, sorry for the confusion! The correct Pacbrake Alpha HD air bag kit for your 2024 GMC Sierra 2500 AT4 would be the part # PB56SV. This comes with the 2 inch spacer you would need for the AT4 so it's for sure the correct kit and will work great for you. Were you wanting a compressor kit as well?
    view full answer...


Info for this part was:

Employee Jameson C
Expert Research:
Jameson C
Employee Dustin K
Video Edited:
Dustin K
Employee Daron K
Edited by:
Daron K
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Written by:
Dawn Z

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