Rear airbag conversion

[Bestcoast]

Thought I might post this here because I hadn’t seen much about doing this or the Firestone kit. I use my truck and after putting a 2” level on the front wanted to avoid excessive rear end sag when towing or loading the bed heavy.

I thought about 1.5” rear lift coils but I didn’t want to end up with factory style rake again. I started down the rabbit hole of rear airbags. I came across the firestone 2595 airbag coil replacement kit. It’s relatively basic, you get the two airbags with mounts, some air hose, Schaefer valves and a mount. I found it for around $400 and for that price I was sold especially when compared to other kits (kelderman) etc. The type of airbag firestone uses is also different than the other kits and appears to have more travel.

This isn’t my first time messing with suspension or lift kits so I felt pretty confident I could get this installed easily. It took about 4 hours taking my time. The instructions from firestone weren’t great but if you’ve installed rear coils it’s the same process to drop the rear axle down far enough to get the coils out.The airbags are held in place by a plate that clamps the upper coil bucket and a small bolt that threads into the lower mount from underneath the coil perch on the axle.

After taking some measurements I set both bags to about 40psi. All in all I’m impressed with the kit and I’ve already started looking into doing on board air so I can adjust the pressure on the fly for different loads. The ride is also better than stock so that’s also a plus.

The first pic is what happens when you put a yard of crushed granite in the back of your truck and the others are during the install. I’ll get some more of the final product later.

 

[Neurobit]

Nice write up. Thanks for posting.
How’s the ride compared to stock?

 

[Bestcoast]

Nice write up. Thanks for posting.
How’s the ride compared to stock?

With the airbags set at about 40psi it sits level with the front that’s got a 2” spacer on it. I’m a fan of the ride so far and it’s softer than stock. The best way I could describe it is that the back floats over most bumps.

 

[mike_ct]

very cool. I've been looking at this kit for a while now, I just couldn't find anyone else that was running it.
nice to hear it rides nice. hope you can put up some pics with and without a load. I'm interested in this for trailer towing.

 

[Bestcoast]

very cool. I've been looking at this kit for a while now, I just couldn't find anyone else that was running it.
nice to hear it rides nice. hope you can put up some pics with and without a load. I'm interested in this for trailer towing.

It rides great. there’s definitely some trial and error with manually setting the pressure to get it leveled without a load but I’ve been looking at the auto level kit from timber grove enterprises. They make a cool bolt up solution for a compressor, tank, and mechanical leveling valves for our trucks.

 

[Bestcoast]

this is with the bags at 50psi unloaded which seems to be just higher than factory rake front to rear.

here’s what the bags look like mounted. These roll/unroll up or down depending on weight/pressure and travel. They look different than the other style of bag that you see that has bellows.

here’s what the airline routing looks like on the pass side. I’m not a huge fan of the style of line that was included. It came coiled and was a huge pain to route. I may replace it later if I have issues with a stainless line.

this is the airline hookup at the bag. They come with a screw in swivel fitting. It’s tight but there’s plenty of clearance.

this is where I mounted Both schrader valves using the supplied bracket. Not a huge fan because it’s a pain to get to put I didn’t want to drill holes in my bumper at this point knowing I’ll probably get on board air.

this is the passenger side just for reference.

 

[Nukegm426]

Drill holes right above the license plate and mount the Schraders there. It’s what we did when I used to work at 4wp. Easy to get to and looks clean.

 

[Dank]

Can you raise the rear like a lift kit (like 2”)?
Also does it replace the rear shock?

 

[Bestcoast]

I t

Drill holes right above the license plate and mount the Schraders there. It’s what we did when I used to work at 4wp. Easy to get to and looks clean.

I thought about it but I wanted to see how I liked it first. I may end up doing that before I get a compressor.

 

[Bestcoast]

Can you raise the rear like a lift kit (like 2”)?
Also does it replace the rear shock?

You could add air to lift the back or you could put a spacer in to add more lift.

 

[LaxDfns15]

You could add air to lift the back or you could put a spacer in to add more lift.

Hey sent you a PM about your springs, but I'll ask here too. Can you see if your OEM springs are the same height? Could you get the part numbers from the tags on them? Trying to eliminate the height difference in the rear on my truck.

 

[jermball623]

I'd like to see if they level it out with a load in the bed or pullin somethin heavy. May do this got in coil bags now, but would do this if they leveled out a load.

 

[Bestcoast]

I'd like to see if they level it out with a load in the bed or pullin somethin heavy. May do this got in coil bags now, but would do this if they leveled out a load.

I’ll get a pic next time the truck has a load on it. The bags should level just like the coil bags or any helper bags.

 

[Bestcoast]

Hey sent you a PM about your springs, but I'll ask here too. Can you see if your OEM springs are the same height? Could you get the part numbers from the tags on them? Trying to eliminate the height difference in the rear on my truck.

Hey sorry I was out of town when you sent that. I believe the part number is the same on the springs but I’ll get a pic of the tag for you.

 

[Bestcoast]

Hey sent you a PM about your springs, but I'll ask here too. Can you see if your OEM springs are the same height? Could you get the part numbers from the tags on them? Trying to eliminate the height difference in the rear on my truck.

This is the rear spring part number. They’re the same for both sides.

 

[KPBlue]

Can you share where you ordered this kit from and the part number? Just got some 5100's for the front and this is exactly what I want to do on the rear.

 

[jermball623]

Amazon.com: Firestone 2595 Air Spring Kit: Automotive

Buy Firestone 2595 Air Spring Kit: Air Suspension Kits - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

I found it on amazon for uner 400

 

[KPBlue]

Amazon.com: Firestone 2595 Air Spring Kit: Automotive

Buy Firestone 2595 Air Spring Kit: Air Suspension Kits - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

I found it on amazon for uner 400

Good find, thanks. Cheapest I had found was 450.

 

[Cross88]

Awesome set up, how low to they go? I’d be curious to see if this would be a better solution for my lowered truck instead of lowering springs and airlift 1000 helper bags. But another concern of mine would be strength/reliability of the bag. I’d hate to be on a road trip towing my TT and have a bag go out on me.

 

[Bestcoast]

Awesome set up, how low to they go? I’d be curious to see if this would be a better solution for my lowered truck instead of lowering springs and airlift 1000 helper bags. But another concern of mine would be strength/reliability of the bag. I’d hate to be on a road trip towing my TT and have a bag go out on me.

I think the only issue you might run into would be having super soft springs in the back making it feel a little boat like but I’ve run them at pretty low pressures and they are comfortable for me. They go low enough to basically tuck a 35” tire.
As far as reliability concerns for me the biggest ones are the lines and fittings not necessarily the bags themselves. The kit comes with cheap lines and okay fittings but there’s better options out there for sure. With that being said I haven’t experienced leaks or anything like that and I daily drive the truck.