Aerostars are very versatile vehicles, but as they get older, the suspension starts to sag, the shocks weaken (dampers to the European crowd), and the overall handling starts to deteriorate. Then there are always those like myself, who use the Aerostar to handle significant amounts of weight, and need the van to be able to do so safely. To many it would seem that the Aerostar would be a fairly unpopular platform for upgrades.

Fortunately, this is not the case, the Aerostar platform is fairly well supported as far as suspension components are concerned. A wide variety of shock absorbers are available to give varying ride qualities. Springs are slightly less supported, with the front springs on E4WD models being difficult to find aftermarket. There are also a variety of other suspension related parts which can improve cornering, improve load handling, adjust ride stiffness and ride height, or make the ride smoother. Finally, there are a number of tire choices. Tires can make a huge difference in the ride qualities, and using a non-stock tire may be advantageous if you are trying to gain a specific quality.

Shock Absorbers (Dampers)

Lets start with shock absorbers. The purpose of the shock absorber, interestingly enough, is not to absorb shock at all. That is what the springs are for. What a shock absorb does is dampens the motion and gives a resistance to the spring rate. Without these, the vehicle will quickly bottom out from even mild ruts and bumps. They also arrest the bouncing action that is set up when the springs have been loaded. A good way to test the shocks is to attempt to bounce the vehicle. Once the bounce force has been applied, if the vehicle continues to bounce up and down more than 2 times, the shocks are probably not adequately dampening the motion. Another test is to travel down a road across some ruts. If the vehicle sets to bouncing so that it bottoms out at the bottom of each crest, you definitely need new shocks.

While it would seem that a softer shock would provide maximum rider comfort, this is not always the case. The Aerostar is a fairly heavy vehicle, and most of the softer shocks, while significantly better that worn shocks, cannot really dampen the heavy vehicle very well on rougher roads. As a result, a mid-grade shock or a firm shock can actually provide a better ride on rougher roads. Even on smooth roads, the firmer suspension can actually iron out minor bumps better than a soft suspension can.

I do not mean to be partial to brands, but some shocks, and some brands altogether are better than others. I have used Monroe Sensatracs and Reflex shocks, and thought they were ok, but when I used the KYB Gas-a-Just on my daily vehicle, I was immediately impressed with them. I also have a comparison between the vehicle with Sensatracs versus a vehicle with bad shocks. The Sensatracs do ride better, but on some of the same sections of road the Sensatracs cannot control the bouncing motion. The Sensatracs are also overwhelmed by sharp bounces such as speed bumps and railroad tracks. The KYBs at the time of this article have far more miles on them than I've ever put on any sets of Monroe shocks, so KYB seems to last longer too. In contrast my impressions of the Monroe shocks has been poor, and I would rate them right with using Bosch plugs on our beloved vans.

The shocks that I would recommend for ride comfort would be:
KYB GR2 (about equivalent to OE)
KYB Gas-A-Just
AC Delco
KYB ExcelG
Monroe Sensatrac (Included because they may have improved the design since the ones I tested. However, you get what you pay for)

The shocks I would recommend for load handling are:
KYB Gas-A-Just
Monroe Max-Air
Monroe Sensatrac Load Adjusting (These are the ones with the coilovers which improves ride height.)

Springs

Springs are slightly less supported in the aftermarket, depending on the vehicle you have. 2WD models have a descent number of options, while 4WD becomes more limited. The primary function of springs is to provide ride height and to allow the tires to move with the road surface without directly transferring this motion to the vehicle. As the springs age, they loose some of the springiness, and they sag. This reduced ride height makes it easier to bottom out which has a detrimental effect of comfort and handling.

The OEM springs are pretty good, but are expensive and are getting harder to find. They were available in both standard and heavy duty configurations, with the heavy duty units being stock on the E4WD models. In my opinion, the HD version rides better, which really means the standards are the cheaper spring. In the aftermarket, there are fewer choices. This is more so of the E4WD models. Most of the aftermarket springs are roughly equivalent. Most that are listed as a variable rate will be good at both ride comfort and moderate cargo capacity. There are many factors in a spring, and unfortunately many of them are not well publicized. I will attempt to sum up or groups the springs based on what they are good for.

Springs for 2WD
MOOG (2WD only) Variable load, available for front and rear
AC Delco (2WD only) Variable load, available for front and rear
Husky (2WD) Variable load, available for front and rear
Raybestos (2WD) Heavy Duty, available for front and rear

Springs for 4WD
AC Delco (4WD) Variable load, rear only
Husky (4WD) Variable load, available for front and rear
Raybestos (4WD) Heavy Duty, rear only

While it seems the options are limited for heavy duty upgrades, don't loose hope, you can use just about any spring and use other upgrades with them to increase load handling. One such upgrade is the coilover shocks listed above.

Air Rides

This upgrade is simple and effective. This upgrade can improve both load handling, and also makes cornering feel more solid and stable by reducing body roll. There are several kits available, and all work on the same principle. A rubber or plastic bladder is filled with an air charge to act as an air spring which helps support the vehicles weight.

The most common type of air ride works by inserting a rubber bladder inside the coil springs. They have an air line that allows the pressure inside to be adjusted to increase or decrease firmness and ride height. This air can be added with an ordinary air compressor, or an onboard compressor can be mounted for easier adjustment. Several companies make these kits, and all of them are approximately the same in terms of quality and results. The most popular and readily available brand is Air-Lift. For the record it should be noted that this type of kit does have its problems, namely that the bladders do not last forever. The bladders can rupture at any time due to either defects in manufacturing, wear and tear, or over-pressurization. Even so, they are relatively inexpensive to replace. These reduce the need for a rear sway bar, since the added stiffness controls body roll. If you want roll resistance without added stiffness, consider a rear sway bar instead.

Another type of air ride consists of a self supporting bladder. These can handle more weight than a coil insert, but are also harder to install. They typically work by mounting to the frame and the axle. Some kits also replace the factory springs altogether. Like the inserts, they have an air line that allows the pressure to be adjusted. Since they do not rub against any coils or other moving parts, they also last longer than coil inserts. The downside is that an Aerostar specific version is no longer made, so they can be hard to find, or a kit with a desirable ride height can be adapted. The most popular brand is Air-Lift, but Airbag-It makes the spring replacement type kit. Airbag-it also makes a kit for the front as well as a complete kit for front and rear.

The last type also works on similar principles, but replaces the rubber stop with an adjustable rubber stop which comes into play when sufficient weight is added. This means a lightly loaded vehicle will ride softly, and once weight is added it stiffens appropriately. I do not know who makes this last type of kit, but I have seen them before, perhaps another member will pitch in on this one.

Sway Bars

Sway bars work by taking a piece of spring steel and spanning between the two sides of the vehicle. This allows the two sides of the suspension move semi-independently, but also move in unison, and gives a resistance to body roll. Aerostars come from the factory with a full 4 point swaybar on the front suspension. Some models use a 3 point swaybar on the rear, which helps, but is generally lacking. Helwig makes a rear sway bar that fits the Aerostar. A rear sway bar dramatically reduces body roll without increasing ride firmness. This is also a useful upgrade for towing.

For upgrading the front sway bar, there are a few things you can do. Replace the stock rubber bushings and links with urethane ones.

Other Suspension parts

The suspension as a whole provides the ride quality. The remaining parts are not adjustable, or really upgradeable per se, and typically only need replacement when they fail, however, there are quality differences.

The front suspension has ball joints, and control arm bushings. These items eventually wear out, and when they do, you get excessive play, clunking, alignment issues, and are safety issues. Most aftermarket parts will get you by, but only MOOG makes a part that can be considered and upgrade. They make the best ball joints, they last a very long time, and are stronger than OE parts, plus they have zirc fittings allowing them to be greased. Many other aftermarket parts also have zirc fittings, but tend to wear out rapidly, giving only a couple years of use before they need to be replaced again. MOOG makes the best suspension parts for the front end.

Alignment is also critical, make sure the front suspension is properly aligned to ensure maximum tread life and to improve corning, braking and safety.

Tires

The stock tires are designed to be inexpensive and provide an acceptable level or safety, tread life, road noise, and comfort. However, the choices are limited by the 14" rims. It is very common for tires that have been inflated to the recommended level to wear out rapidly, especially on the outside edges. This is because the stock tires are a 4 ply passenger tire. Because the cost is fairly low, sticking with a 4 ply tire in a stock size has its benefits, but there are other options especially if a firmer ride is desired or if increased load handling is needed. The larger stock size is P215/70R14

Upgrading to a larger rim increases load handling, but also costs more and finding tires that fit without rubbing can become an issue. You also don't want to stray too far from the speedometer calibrations. This is especially true of AWD models. Most of the upgrade tires for the 14" rims are significantly larger than stock.

The best all around tire for the 14" rim is the Cooper 27x8.5 R14 LT. This tire is not the cheapest choice, but it is only a modest size increase over the largest stock size. If moves the user from the realm of passenger tires into a light truck tire. The upshot is dramatic increases in load handling (up to 3,000 lbs per axle), a dramatic increase in tread life (from 15,000 - 30,000 miles to 50,000 - 70,000), a significant decrease in body roll, and excellent all around traction on dry, wet, muddy, and snowy surfaces. For ride comfort reasons, this tire can be filled with as little as 40 psi and still retain its shape, but when extra load handling is needed, the pressure can be increased up to 55 psi. This tire is available under several private labels, but Cooper is the only manufacturer making this tire. The three major downsides to this tire are the price and the road noise, combined with its relative rarity, most tire shops would need to order these in. Just to recap, the pros and cons:
Excellent tread life
Excellent dry traction
Excellent load handling
Excellent pressure range
Excellent wet and snow traction
Mildly expensive
Increased road noise
Not standard size for shops to stock

In 15" tires, the choices for higher load capacities is still limited due to clearance issues. The largest tire you can use on a 15" rim without any rubbing is 215/60R15. This tire will sometimes rub on the inside edge on the read tires when you hit a hard bump or dip. To avoid any rubbing at all, the biggest is the 205/60R15. This tire is again into the real of passenger tires, so you may gain some load handling, but the tread life suffers. Considering you need to obtain a set of 15" rims that fits the Aerostar, plus the limited choices without rubbing you are probably better off with 14" unless you like the look of 15" rims. The tires may be less expensive than the Cooper 75x8.5 R14s, however. i have no personal experience with this route, but have considered it and keep getting stonewalled by the limited choices that would be comparable to the Coopers.

Please anyone with any experience or suggestions is welcome to pitch in, but this should cover the bases on upgrading and improving the handling of the Aerostar.

 

Okay, what did I...
Shocks: rear - UAZ, front - Monroe.
Springs: rear - cargo aero springs, front: Mercedes E-class rear springs
Tires: european, 14-15" (I have 2 rim kits, 15" for summer, 14" for winter), but Cargo rated tires. They are heavy, but sidewalll is harder and that's why less sway. well, I used to think about 16", but available here rims have a bit different pattern and I wanted to drill addtional lug holes (4.25")....

 

I get the impression that Ford underspecs the tires on a lot of their cars; they seem to be JUST adequate for the vehicle. The load capacity of a tire seems to be related to its size and height, so an extended length AWD Aerostar could really use more tire.

Having said that, I did a quick browse through the web site of one of our sponsors, The Tire Rack, and checked the specs of all the 215/70/14 tires that they have. They all are rated at 1554 pounds, and all except 2 have maximum pressure rating or 44 psi (one at 51 psi). The other size with presumably higher load rating, 215/75/14, does not seem to be available any more. Still this translates to over 3100 pounds load capacity on each axle. Do LT tires give much high load capacities?

You can more easily get higher load tires by changing to a +1 wheel/tire size. Something like a 215/70/15 would be just a little taller than the original 215/75/14, and you can get LT versions of these with higher load capacities.

I just got a set of KYB gas-adjust shocks for my van, and I'm waiting for an opportunity to install them. I found the original dampers that I took off of the van when I installed the Monroe Sensatrac about 10 years ago. They had NO damping left in them at all, so the Monroes felt like they worked a lot better when I first installed them. Of course they did; the originals were totally worn out. But I found the Monroes lost their effectiveness pretty quickly, and it's probably time to replace them anyway. I don't know if their lifetime warranty covers wearing out, vs defects.

The other thing with dampers is that when they're worn out and letting your car bounce uncontrolled over bumps, they are also wearing out the springs. That's a big problem for those of us with the AWD; the fronts are very hard to find replacements for. So it's better to replace the dampers sooner than later. I just gotta find the time.

 

Also sway bar bushings , ball joints & Control arm bushings & tie rod ends are doing overtime!
I just had my Front shocks replaced with AC Delco units {this year}. The ride is 100% better now. I should do the rears too.

 

Oh yes. The weight capacities are similar, but a passenger tire is a 4 ply, while the LT tires are 6 ply. They will maintain most of their load handling even if they are underpressured, try that with a 4 ply. Some of those tires claim to have long tread lives too, but not on an Aerostar. The constant weight is too great.

I have been running my Cooper 27x8.5 R14s for about 65K miles, and they are at about 40% tread life remaining. I frequently haul heavy loads, I have carried over one ton inside the van on multiple occasions, and not short distances either, when I am loaded up, its returning from St. George, about 350 miles. I do this run every three or four weeks. The 4 plys won't do this. I know because I had them when I bought the van. The previous owner put new tires to sell the van, and I got about 20K out of them and they were going bald on the outside edges. The tires were the Michelin Harmony. They were quiet, but they just couldn't take the weight.

Yes you can, but unless you get the 15" rims for next to free, it still costs more to do a changeover. The increase in size strains the AWD systems. Even if it doesn't cause the AWD system to get confused, it does put stress of the chain inside the transfer case when you make sharp turns. The 215/70/R15 is the largest size you can use on an Aerostar without rubbing. In all other ways, this is a good setup. The larger tires ride smoother, can handle weight, and are reasonably priced. The biggest hurdles are the cost of the wheels, and finding the right ones and living with the incorrect speed calibrations.

This is partly why I listed the Coopers as a recommended size. They are almost the same as a 215/75R14, but with the higher ply. Technically these tires will hold as much as 2500 lbs each, at 5,000 lbs per axle. However a 14" rim cannot safely handle that much weight at speed. Since the tires are not even breaking a sweat hauling an Aerostar, they last a very long time. On my van, the speedometer read about 2 mph higher than the actual speed. With the Coopers, they read within half a mph of actual speed. So the Coopers are actually closer to the factory speedo calibration than the stock tires.

As mentioned, the only downsides to this tire are price and noise. In all other respects, they are awesome.

I expected tires to be the area of greatest discussion, and maybe even controversy. There are a lot of choices out there, and they are many reasons to choose one tire over another. Weigh the reasons in the balance, you have to decide which factors are important to you.

This tire is available as a private label through Tire Factory location, and I'm pretty sure the Maxis Bravo is the same thing too. Cooper is the only company still making this size. You can also get them through Big O tires. Expect to pay around $115 per tire for this size. Some locations may charge a little bit more, depending on how hard they are to get.

 

Because this topic is intended to help users upgrade the stock suspension, this should probably be a sticky.

 

Khan,
Good thread. Nice to have this all compiled in one subject.

I'll offer my experience and opinions on the topics.

SHOCKS: I just put KYB GR2 on the fronts and KYB GasAdjust on the rears. They do firm up the ride - almost to the point of being too firm on the fronts. Every bump takes on a solid hit feeling as if you had run over a 2x4 with your old shocks.

SPRINGS: I have the E-4WD version and replaced both front and rear springs with aftermarket Husky as I could not locate OEM sets. Rears are variable load configuration and seem to support the rear well and offer decent handling and suspension tasks. Fronts are another story. Original OEM springs are 3/4 inch thick stock. Big, beefy springs. Aftermarket are a narrower gauge (5/8") and taller by 1 inch. At first I suspected my OEM springs had sagged that much. Now, I believe the extra height on the Husky is to compensate for the smaller diameter coil to give an equivalent compression force once installed. In any event, the new ones bow outward instead of riding perfectly vertical as the old ones did. Would I recommend them as replacement? Only if you must replace a set due to breakage or damage. BTW, my old ones had over 200,000 miles on them. I just pulled them out of the corner of the garage and measured them yesterday and found both were precisely the same height - no sag on the driver side. My experience says these OEM springs were build to last and my old set will go back into service with the next suspension repair.

AIR RIDES: I have used Gabriel Hi-Jacker air adjustable in the rear and found them to be an excelent way to keep the rear level when towing. I tried the Air-Lift (intra coil airbags) and was really disappointed in them. They would not maintain a constant inflation pressure. When the pressures go down the bag sides will rub the spring and eventually wear a hole. My experience says airbags are a waste of money.

TIRES: Discount Tire offers their in store brand 'Arizonian" in original 215/70-14 size for only $58/each. I put a set on recently and so far I like them.

 

Good points. However, I have met a fellow who used the Gabriel Hi-Jackers, and keeps shearing off the suspension mounts. The shocks are meant to dampen the load, not support the vehicles weight. His vehicle was a Windstar, don't know if the Aerostars mounts are tougher.

The Airbags can be replaced cheaply. I previously had a set, but they could not compensate for the worn out springs. When I replaced the springs, the airbags had molded to the shape of the old springs such that they could not be reused. Never had a problem with them loosing pressure. I recently put a new set on, this time around with the on-board compressor. I like the way they ride, and when they blown, replacements can be had for only $35. If I get a couple years out of a set, I got my money's worth.

The ultimate air ride is still the Air-Bag-It system that replaces the coil springs entirely. Not the cheapest route to go unless you need new springs anyway. The bags are the same type used on big rigs, cement trucks, and gravel trucks to firmly support the loads. Different size obviously, but made by the same company the same way.

 

IMO. Air suspention is good if it is complete ECAS. 2 height sesnors. dual height solenoid valve. it is a good level controll that lets to decrease risk of roll over. But to work well good compressor required. I used to think about Mercedes Air Matic compressor by wabco ore about MB Vario compressor.

 

As I am in the processof buying parts for a suspension make over on my 97 2WD XLT, I was glad to come across your post. I am having trouble finding the Raybestos heavy duty rear springs, do you have a part number for them? Thanks.

 

RockAuto Auto Parts

RAYBESTOS Part # 5871046 More Info {Professional Grade; Sold in Pairs -- Inside Diameter=4.07" Wire Diameter=.735" Free Height=11.65" Load height=10"}
Front; Two Wheel Drive (4x2)

RAYBESTOS Part # 5911034 More Info {Professional Grade; Sold in Pairs -- Inside Diameter=4.3" Wire Diameter=.531" Free Height=18.69" Load height=14"}
Rear Variable Rate; Two Wheel Drive (4x2)

RAYBESTOS Part # 5871080 More Info {Professional Grade; Sold in Pairs -- Inside Diameter=4.3" Wire Diameter=.531" Free Height=20" Load height=14"}
Rear Variable Rate; All Wheel Drive

 

OK Thanks for that. But what about those springs is heavy duty? I am primarily interested in the rear springs. No where are the spring rates published that I could find. Judging from the specs given I would have to say that the Raybestos AWD rear spring is softer than the 2WD rear spring being that the AWD spring has a longer free height but the same load height as the 2WD spring. That is the opposite of the information published about the Moog springs, as for their springs the AWD has a higher spring rate than the 2Wd spring even though they both share the same 4.3" ID, >531 wire and 14"load height.

Does any one have any better knowledge as to what is the most heavy duty spring that will fit the rear of an Aero without modifications?

 

never seen Ford publish spring rates or specs.
much of the Ford OEM info has disappeared in the past 12 years since end of production. much of the info was Ford OEM manuf. proprietary.
Ford still protects their service manual and literature copyright rights on the Aero. they can be aggressive about hunting down and turning the attorneys from hell loose on any freebies.
best to call the aftermarket manufacturers for load ratings on their springs.

springs will vary between manuf's even though their published sizes are the same, different steel used and different heat treatment.

have Husky Spring make a set to your specs.
Husky Spring: Suspension Parts, Leaf & Coil Springs

I find the standard AWD springs with rubber spacers in front and upgraded poly bushings, air bags in back with a Helvig swaybar, with KYB high pressure nitrogen shocks all the way around more than sufficient for 500 lbs in the van and another 400lb hitch weight plus a 4,000lb trailer behind.

best way to make the springs last far longer is use top quality ie expensive shocks that are high pressure nitrogen and replace them at the least sign of wearout.
KYB, Koni and Bilstein are the only ones making shocks now that I would put on a wandering, wiggley top heavy Aero. Koni may have dropped their Aero product, Tokico did

not a rig that is designed to carry more than 1,000 lbs all the time.
heavy loads on the rear axle eat up the poor design axle bearings and axles. no aftermarket manufacturers and junke yard replacement axles are disappearing fast. prime crusher for China

 

With all due respect, that still doesn't help me. Moog states this for the 2WD rear springs: Inside Diameter 4.3", Bar Diameter .531", Installed Height 14" Load rating: 482 lbs. Pigtail ends

For the AWD springs: Inside Diameter 4.3", Bar Diameter .531", Installed Height 14" Load rating: 616 lbs. Pigtail ends

All I really need to know is if I can fit the AWD rear springs on the rear of a 2WD Aero without any modifications? What is the difference in the rear suspension between an AWD and a 2WD Aero?

 

Unfortunately these guys are correct. Ford has protected the original specs and the aftermarket is not very open about theirs either. I have Moog on mine, and have to say they were disappointing. OEM springs are best, but are getting hard to come by. My take on springs is to go with the best you can. The better ones are the ones I put in the HD section. You can further raise or stiffen the rear with air rides, or you can replace the springs with air bags.