Firestone Ride-rite air bag helper springs

RH,, wheel base makes sense.

Has anyone put these on a 4x4? Quigley puts a 3" spacer under the springs, I'm assuming a spacer could be added under the air bags, but I have no experience.
Doug

BlueBlaze, I have to question whether  the air bags are properly installed. I had them on a 2005 Dynamax (E450 Ford, B+) and usually ran 30 pounds which raised the rear 2”. 65 pounds would raise it 4” but roughened the ride. As you add air the rear of the coach should rise. You might want to leave all of the air out, have someone crawl under the coach and watch as air is added to figure out why the height doesn’t change as the bag expands. Mine were a big help to the sagging problem and helped with the handling as long as I didn’t go too high on the pressure.

BlueBlaze, I have to question whether  the air bags are properly installed. I had them on a 2005 Dynamax (E450 Ford, B+) and usually ran 30 pounds which raised the rear 2”. 65 pounds would raise it 4” but roughened the ride. As you add air the rear of the coach should rise. You might want to leave all of the air out, have someone crawl under the coach and watch as air is added to figure out why the height doesn’t change as the bag expands. Mine were a big help to the sagging problem and helped with the handling as long as I didn’t go too high on the pressure.

There's not much opportunity to screw it up.  They simply bolt on.  The bottom brackets are clamped to the axle with U-bolts and the top bracket wraps around the frame and bolts to a hole (the only one) in side of the frame.  They are effectively in parallel with the existing springs, not on top of them.  So unless the load is significantly depressing the leaf springs, the air bags don't really come into play.  Since I haven't had the opportunity to load the rig for a trip, I've never seen how they handle under a load.  I'm pretty sure they would raise the rear when it sags from the 400 pounds of water weight on the rear wall, but I couldn't see any measurable change when its unloaded and not sagging, even at the max 100 pounds.

They make different versions of the bags.  The double-convoluted bags don't look like they are designed to actually change shape under a load, but merely resist being compressed more as you add more air.  Maybe the conical version works the way you describe.  

But I'll give it another look this weekend.

Does raising the rear end require realignment?

Does raising the rear end require realignment?

No, not in the use that we are discussing- raising the rear of the coach to get back to level.

In the case of wheelchair van conversions like this -



We often had to adjust caster because the back was higher than stock. It would 'wander' terribly otherwise.

my 2350 measured  32.5"  at 40psi

Blue Blaze - if  your 2008  measured 33.0" at zero psi maybe the previous owner replaced the springs or added a leaf to fix the sag.

my 2350 measured  32.5"  at 40psi

Blue Blaze - if  your 2008  measured 33.0" at zero psi maybe the previous owner replaced the springs or added a leaf to fix the sag.

I guess that's a possibility, but it still sagged or I wouldn't be looking for a fix.  Whatever it is, apparently it's just my rig, or maybe the kit I used wasn't correct for a 350.  The part number on the box seems correct, but if the only difference between the e-350 and the kit for a standard econoline van is the size of the bag, there's no way I would know the difference if Amazon swapped it on me. Maybe I got someone else's return. 

I did some more testing this week, after driving it around some.  I added air in 10 lb increments, while measuring for a change at the tow hitch.  This time I found some change, but it seems to be more because of where I measured it than anything else (it still measured about 33" at the wheel well).

Starting with an empty coach, no water in the tank, and zero psi, it measured 14.0".  Every 10 lbs added about 1/8", up to a max of 100 psi and 15.5.  30 psi (the minimum allowed) was 14-3/8".  The maximum lift was only 1-1/2".

So then I filled the water tank (to add 382 lbs on the back wall) and tried again.

At zero PSI, it measured 13-5/8"  (3/8" of sag).  It still added about 1/8" for every 10 psi until I reached the maximum 100 lbs and 15-1/8".  So the maximum change was still 1-1/2".  (I know those numbers don't add up to exactly 1/8" per 10 lbs, but it's close).

Bottom line -- I simply didn't get any improvement worth the $400 I spent.  However I can say that at 40 lbs, it did level the coach to the same height without water, so I guess the bags did what they're supposed to do (just not what I hoped they would do).

I double-checked the installation and could find no errors.  The springs appear to be stock, but I'm not sure I could tell if they weren't.

The kit is Firestone W217602061.  Maybe there is a different kit that would give a better result.  But in any case, I would definitely recommend against wasting your money on this kit if you are looking for improved ground clearance on a 2350 coach.  Maybe it would be worth it on a coach with a longer overhang than the 2350's 8 ft, since the leverage effect would increase the rise.

If you have leveling jacks maybe check if the suspension will extend any further than 33”-34” with with zero weight on the springs??

If you have leveling jacks maybe check if the suspension will extend any further than 33”-34” with with zero weight on the springs??

There's certainly no hangup there.  I actually did this while I was installing them, before I had the air hooked up, to get more room to work on the air lines.  When I jacked it until the wheels were off the ground, it extended the suspension so far that the folds in the airbags were gone and made them look like elongated prunes.  I realized that was probably very bad for them, and let the jacks back down until they looked normal again.