Is an Alignment Needed After Installing Coil Springs

Question:

I have a 1999 Ford Superduty with 7.3L. I have installed rear air bags to assist in towing a 10,000# travel trailer. The rear end is now sitting about 3 inch higher than front of truck. If i install the supercoils and raise the front end by 2, will the supercoils cause a problem with front end alignment or geometry? The front suspension is stock. This is a follow up.... The correct Air Lift bags were installed. They raised the rear an additional 2inch for a total rear end lift of 3. Weather I install Supercoils or 2inch lift bushings on the front end, will it change the geometry caster/camber of the front end requiring a 4-wheel alignment?

asked by: Mike P

Helpful Expert Reply:

The rear of your truck should only be raised while the airbags are inflated and the vehicle is unloaded. Once the vehicle is then loaded, the airbags should drop back down to stock ride height. If the rear of the truck is higher than stock while the vehicle is unloaded and the bags are deflated, then the airbags may have been installed incorrectly. I would clarify this before moving forward.

After installing a set of coil spring on your truck you will indeed need to do an alignment. However you will want to wait a few days for the springs to settle before you perform the alignment. It will take a few days of driving and weight bearing activity in order for a set of coil springs to settle in their predetermined ride height. If you decided to install a set of coil springs, I recommend the SuperCoils Custom Suspension Coils part # SSC-30. Keep in mind that you have a solid rear axle and a 2-wheel alignment is all that need be done. A 4-wheel alignment is for vehicles with an independent rear suspension.

Another measurement you will need to take into consideration when lifting a vehicle is pinion angle. Lifting a vehicle can throw off the pinion angle which in turn affects the vehicles steering. You will need to have the truck taken to your local mechanic in order for this to be checked and adjusted.

expert reply by: Conner L

Jim P.

1/14/2025

I am trying to decide which item to purchase. My '03 F 350 Diesel Dually has 380K miles, and the front springs are about 3" down. We put a 2,800 lb. slide in camper in the bed (that's the actual full weight...not manufacturer's made-up number), and it's a rough ride. I think that the camper is probably pushing down on the bed and lifting/decompressing the front springs. I put new Bilstein 4600's all around and rubber bumpers under the seat mounts, which really helped, and I like the raked look of the truck when it is unloaded. I am a little over 7 foot, so I removed the dumb fold-down sun visors and can't put in air ride seats because of head space. I am trying to decide between: 1. Firestone airbags to lift it up a few inches while towing 2. New SSC-30 springs. My concerns are that the airbags might not last long and that the SSC springs will make the ride rougher. Which if any do you recommend? Thank you for any input you may have!

Jesse M.

1/14/2025

@JimP Hey Jim, thanks for reaching out. Between the two options you mentioned, I would lean towards the air bags. The SSC springs will make a difference, but they can make the ride more rough since they really only have one setting and they aren't adjustable. The air bags will allow you to fine-tune your suspension to where you can get the ride leveling without making things too rough. The Firestone air bags especially have a very durable construction with the rolled crimp seal. We do not hear complaints about the longevity of the springs so that is not something I would worry about. For your truck the Firestone # F2223 is what you need for the front end. Part # F2550 is for the rear.

Jim P.

1/14/2025

@JesseM Thank you for the quick response. I think I'll wait until warmer weather to install, as the airbags need to be more pliable to squeeze between the coils that are already compressed. Your videos on the website are very helpful and appreciated!