Suspension Upgrades/ride quality

Alright, I’m looking at overhauling my suspension on my 96 RMW non tow pack to handle heavy loads in the back, haul a trailer, handle better, but still have a reasonable ride quality unloaded. I don’t like the unpredictable boat-ride handling now so I’m happy to go quite a bit stiffer, I just don’t want to overdo it. I wouldn’t mind some more ground clearance but it’s lowness may just be due to saggy springs. During a recent work trip, I had enough equipment in the back and on the roof to nearly bottom the suspension while sitting still. I’m hoping these upgrades help with what feels like lateral motion in the back.

So here is my plan:

Front:
Monroe severe shocks- 550012
Moog springs 5030
Poly sway bar bushings (already complete)

Rear:
Monroe severe shocks 550013 (already purchaced)
Moog cc621 (what’s the difference between 621 and 623?)
Air lift bags
Crown Vick sway bar
Hitch
Maybe poly LCA bushings

Do you recommend poly control arm bushings in the front? Do it now or down the road?

Am I supposed to do anything else when I do springs, like the isolators? This will be my first time replacing springs.

How do y’all think that will ride?

Any other tips? Going to be doing the rear brakes and diff oil while I’m at it. Worth doing wheel bearings?

Thanks guys!

Colin

I have similar goals with my 96 RMW - I took a slightly different approach which you may/may not want to consider.  It's also not proven out yet so, there's that .  The wagon has a lot of length from the rear axle to the back of the car, so when you put a load in/on the car and possibly include a trailer and it's loads, the rear suspension has a lot of work cut out for it.  Even going from empty to full on the gas tank makes a significant difference due to it's location and the long lever to the rear axle.

Convert to rear coil-over's with springs of a rate that gives you acceptable ride quality (300 lb-in range).  Set them to the ride height about an inch below where want the car to be at unloaded (or whatever you always carry in the car with you).  If you get adjustable dampers, you can further tune the ride harshness over bumps.

Install airbags in place of the rear coil springs - many options, but something like this is what I'm considering.  

https://www.ridetech.com/product/air-spring-1700lb-rear-rolling-sleeve/

Use the existing suspension leveling system in your car to modulate the pressure in the airbags to maintain ride height and suspension travel.

These airbags are rated for 1700 pounds (each) at 100 psi, so with the coil overs taking up the majority of the weight of the car, the airbags only have to contend with the added cargo so they will likely only ever pump up to 30-40 psi, max.  This is well below what the original air shocks would run at (over 100 psi), so the compressor should be able to handle this easily.  Use the factory sensor and linkage, adjust so the airbags lift the car up to the normal ride height so they have some air in them and are always "active" so when the suspension extends they can move freely.

Here's a (poor) picture of what I'm trying to describe



Anything with typical coil springs only will be a compromise and likely involve a few iterations to get it where you want.  I'm not a fan of airbags inside coil springs, it doesn't really address the problem (adding more force), it just adds more friction which is not what you want in a suspension.

Rear Springs are easy, unbolt the shocks, and the springs literally just about fall out.  Set the new ones in - you can put in new rubber isolator rings or re-use the ones you have.  The rubber rings are available at Rock Auto for pretty cheap.

Front springs are a different story - More like handling a live grenade, while you're shivering cold, and whacked out on Meth.  There's an enormous amount of potential energy in the front springs since they nee to be compressed to install them.  It can be done, but be careful.  Invest in or rent a quality spring compressor.  If the control arm bushings are shot, now is the time to replace them.

Here's a better picture, but without the airbag - it would go where the coil spring goes...

I would leave the springs alone. The proper shocks and internal airbags in the rear springs (hooked to your ALS) would achieve the ride you want. I would not replace the bushings with poly. The poly bushings will make you have a harsher ride. Adjustable shocks would allow for fine tuning, but the rear shock mounts on the axle are not made to carry the load of the car.

Spring isolators are designed to quiet the springs against the frame. Without them you can get squeaking, and the can transmit road noise.

While you are changing the differential oil, it would be a good idea to check the wheel bearing and axles. The right axle is the most likely to have wear. If the axle shows a wear groove, then you need to change the axle as well as the bearing. A "quick fix bearing" is not the answer. They do not last long, and you will be redoing it with a new axle anyway. Moser makes excellent axles, and they are about the same price as the ones made in China, or India. If you have an LSD, put the modifer in first, then fill with the oil. Always put a new bearing in with a new axle.

I tried a Crown Vic bar, and did not have a good experience with it. I am considering the aftermarket anti roll bar for the rear. A rear anti roll bar will cure a lot of the rolling that makes the car feel sloppy. I have the whole CV setup with the 21mm bar, and it is available for $100 plus shipping. If you want to reduce the amount of sway, put the poly bushings, or dura-aluminum bushings in the upper rear control arms. They are what keep the axle from moving side to side. I would put stock bushings in the lower arms to keep the ride compliance that you like. Make sure you flare the outer shell/tack weld them, or the arm can dislodge from the bushing.

I have set our 96 RMW up similar to what you are saying. I wanted normal ride height and clearance to the road, decent ride, very good handling for general summer driving, hauling, some towing but still nice enough ride to go for a 200 mile cruise in the country comfortably.

I put in stock replacement MOOG springs in the front and Airlift 1000# bags inside the existing rear springs. All the suspension parts have been replaced or the bushings replaced. KYB shocks for a couple of years and Bilsteins now. Both were good but Bulsteins a bit more control a a bit better ride quality.

It had stock 1.100" front bar and I put in a Crown Vic bar in the rear and it improved the handling a bunch, but along with the engine, gears, etc changes I have now put in a set of Hotchkiss hollow matched bars front and rear. I hope they aren't too stiff. Still a few weeks to finish it up and hit the testing road.

I was never happy with the steering feel, so I got a steering gear built with a fixed 14 to 1 ratio and 31# torsion bar in it which helped a lot. It was impossible to get more than about 2.5-3.0 degrees of positive camber in it, so I cut apart the upper control arms and welded them back together so now I am running about 5.5-6.0 degrees and it made a big improvement. The camber at stock height goes positive progression on bump, so I put in tall upper ball joints to change the progression to negative and now also align at -1/4* degree negative and got better centering and smoother mid turn with slightly slower turn in.

About all I didn't like up to this point was that it felt like it needed a bit more swaybar, particularly in the rear, but also in the front a bit. At stock ride height I am sure it needs a bit more than the lowered wagons would need. Hopefully, the Hotchkiss bars will take care of it without causing problems.

We had the 2.56 axle ratio so I am changing that to 3.23 with Trutrack locker. New engine will be similar to stock torque curve shape but more cam lift and other general improvements parts quality which should give a bit more torque and horsepower. Hoping to get rid of the some of the irritating downshifting all the time on the highway. Stock torque converter.

You may want to take it to the scales when you are fully loaded to see where it is at. There is always a concern of tire overloading or even axle overload and breakage

5030 and CC621 (or 3)... are you trying to make a monster truck?

Fred's advice is where I would go, personally. You definitely don't want, or need, poly bushings on a street car. They will annoy the crap out of you.

Thanks for the thorough responses! This is why this forum rocks.
Haha I don’t want my “Roadmonster” to be monster truck height, I just searched for the cargo coils PN and the 9C1 setup.
So I’m limited in terms of budget and time. I think without a welder and working my myself it would be best to keep it simple for now. I know coil springs would be a great option but they are a little out of my wheelhouse right now.
Are the springs really going to be that bad? Are the listed ones the 9C1 setup? That’s what I was replicating. I figured that was an engineered setup and would be reliable.
Booster, that sounds like a great build. You have clearly put a lot of through into that suspension. I’ll be happy to hear how it performs when you are done.
Got it, no poly. It’s less work anyhow. Haha. Anyone have success boxing control arms?
Annoying downshifting? Heck yes. 55 MPH is like right between gears and it gets really annoying. Haha same thing between 2nd and 3rd at like 35 ish. I dream of new gears, but step by step..... lol
So maybe a good plan for now is just put on the Monroe’s front and back and sway bar? I already have the bar so kind as well. I can see how it works and go from there.
I also wanted the heavy springs in the front to help with a tire rub issues the passenger side. The body mush be shifted a bit and the extra clearance would help on big bumps. I’ll get around to fixing the actual issue at some point...

Thanks again, folks.

I sort of boxed the rear lower arms when I put in the Hotchkiss swaybar as it uses the stock style mounting to the lower arms. I built an adapter that slides inside the arm and across the bottom. Bolted to the sides of arms on both sides of the arm and also with draw bolts through the arm, bottom of the adapter, through the sway bar to up it all up tight to the bottom of control arm. It looks to be very strong, but at this point is not welded to arm bottom flange which would be better. If I even have the arms off, I will weld it.

Without a welder, you will be in a tough spot to box the rear arms I think as there is very little to bolt to do it that way. Easy with a welder and the arms off as most of the bottom of the arm is flat. I think I used a piece of 3/16 X 3.5" hot rolled steel bar for the bottoms and it was a good fit full width. If you do try to bolt one on, you might be able to get 1/4" socket head cap screws through the flange with bolt heads up and reachable with an allen wrench, with nuts on the bottom under the added piece.

The Crown Vic bar is quite small, if you have the same one I have here still but replaced. I really don't think it is big enough even at unloaded weight as I still needed to use lower rear pressure in the tires than I wanted to combat a bit of understeer. That is often because of mismatch of antisway front and rear so hoping better matched front and rear gets rid of the understeer. For that reason, I would not go to a bigger front bar unless you can find a substantially larger rear bar than the Crown Vic. If you make the front bar bigger, it may actually make it drive worse than the stock bar. When you heavily load the rear, hard to tell what will happen for sure, but probably will also put a whole bunch of understeer in. Example for us is our 1 ton Chevy van that has been turned into a camper and has l higher roof on it. Runs at near max weight all the time of 9500# and the van came with only a front 1.375" bar and no rear bar. To get the handling relatively neutral, I had to go with an added 1.500" solid bar in the rear and also reduce the front bar to 1.31" diameter. We have about 5200# on the rear axle.

Regarding the 1700lb air springs, shouldn't you be able to run those without coilovers and just standard shocks?  GAWR for the rear axle is about 3250 lbs, so if you're going over what those air bags are rated for (1700lbsx2, so 3400lbs for the axle) you're also going over what the axle is rated for.  You could still use the self levelling compressor as you're within the pressure range and sub in normal shocks for coilovers, which would make this whole setup cheaper.

I think this might be the plan I go with for rear suspension, plus adding in an aftermarket 1" crown vic style roll bar.

You can run the air springs only, however the ELS will run at much higher pressures and they're not known for their reliability .

So having it supplement the coil-overs instead of supporting the whole car felt like a more robust option

Gotcha, I'll probably go for just the air springs and then replace the compressor with something more substantial if it ever fails.

I believe the ELS compressor has all the valving built into it so not sure how easy replacing just the compressor would be. Might be dead simple - just haven't looked into it.

Ride-Tech has full kits for these cars with level sensors, compressors, valves, tanks, etc

We have the 5000# Airlift airbags on our 1 ton Chevy van supplementing the leaf springs, but I did take off the overload leaf from the leaf springs. On thing you always have to think about with bags and either reduced capacity springs or no springs at all is what happens if the airbag pops or they leak down for some reason. Good bags are pretty tough and don't fail very often, but it happens. Leakdown from hoses and connections are far more common. You need to make sure you have some type of bumpstop in in place to make the vehicle driveable if the bags are flat, even with no springs in it. Airlift even has bags now that have that emergency bump stop built into the inside of it to do it all in one place. I switched to that version when I removed the overload leaf on the van. The most common way to do it is to replace the axle bump stop with a Timbren style bump stop overload that is short enough to not engage at all or much until actually needed, but touching on big bumps or super heavy loads can also be a benefit.

Not using the leveling compressor is smart, as it has so little capacity it would take forever to make a pressure change in a big set of bags, I think ours in the Buick used 1/8" lines only. Onboard, reliable, compressors are not cheap and some are prone to failure if driven in bad conditions like deep water or road salt if exposed. Most just carry a "disposable" 12v compressor with them to use as needed.

How well do those sleeve springs bolt up to our cars?  Is their any modification for those to physically fit into place?

As far as the ELC compressor, as far as I know it has a valve to prevent underinflation (which wouldn't be an issue in an all air setup) and the exhaust solenoid and drier are built in, which would be easy to replace or integrate. The wiring is dead simple for them and the brains of the whole system are built into the sensor at the rear.

I would not recommend coilovers because the lower shock mounts are not designed to carry the weight of the vehicle. If you want to use coilovers, you need a mount that encompasses both sides of the shock end, just like the suspension arms have a bolt through for strength.

Fix Until Broke wrote:

Ride-Tech has full kits for these cars with level sensors, compressors, valves, tanks, etc

Just went to their site. Not a bad price on the main parts (bags, arms, etc). Very tempting, lol.

for what it's worth, when i got my wagon at 78K the air ride hoses were shot - never did bother to see if the compressor worked either. I had bilsteins installed in the rear prob around 85-90K?, car went to the yard around 157K and 8 years later. Often had several hundred pounds of stuff in the back (as much as 500). tended to drive it hard/ take corners a bit too fast. Felt it handled great for what it was. took speed bumps like they weren't there. comfy ride, etc. later on i replaced the front shocks too but with ss hvy duty monroes as they were much cheaper.

I've thought about getting rid of the air levelling, but I'll have 3 friends in the middle row and 4 dogs in the back and I'll scrape pulling in and out of my driveway.

Flyingtaco wrote:

I've thought about getting rid of the air levelling, but I'll have 3 friends in the middle row and 4 dogs in the back and I'll scrape pulling in and out of my driveway.

i forgot about the scraping when traversing steep driveway slopes - but that was just one of the tailpipes hanging low due to a worn bushing i didn't get around to fixing for a while