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Fixing or Replacing a Load Levelling System (Air Shocks)

Jeff Bieber wrote (1998?):

This applies to the 1990-93 FWD 5th Avenue and Imperial, and also the New Yorker Salon and Dodge Dynasty for the same years, and possibly '88 and '89. There may be other vehicles, too.

Many times rear load-leveling air shocks are replaced with hydraulic aftermarket shocks. But sometimes this will cause the rear to sag. And because of this, the conversion will sometimes be delayed or avoided.

Supposedly there was no aftermarket correction for this problem. But I discovered that this is not entirely true. I found replacement springs that will more than adequately hold the car up, and will also continue to give a smooth car-like ride.

The solution is to add variable-rate coil springs to the setup, along with the new shock absorbers. These springs are sometimes called wuss springs by racers, because of their softness. But this is precisely what is necessary to keep the smooth ride these cars are known for. In addition, one source stated that variable-rate springs hold up to 600 lbs. more weight than the usual OEM constant-rate springs found on most cars. The difference between the two is that, while constant-rate springs have equal spacing between all coils, variable-rate springs have increasingly wider spacing between coils, starting with the narrowest spacing at the top. A third type of spring, heavy-duty constant-rate springs, have about the same strength as variable rate springs, but will ride like a truck when no extra weight is being carried.

The theory behind variable rate springs is that when the weight of the car compresses the springs sufficiently, the first two coils will touch, essentially eliminating one of the coils. It works the same as cutting a coil off a spring to make the spring stronger.

I had previously had the old air shocks replaced with hydraulic shocks, and this caused an extremely soft suspension on my 1991 5th Avenue. That is, there was about 1.5 to 2 inches of travel in the springs when a minimal amount of weight was applied. I then had these variable-rate springs installed, and immediately solved the problem. The ride is the same quality as before (not hard at all, but you might notice a slight increase in firmness, because the old springs are, well, soft). And there are no aftermarket airshocks to adjust. One thing to think about, though, is that an alignment check/adjustment may be considered after a coil spring replacement.

I found these springs at only one place. It is a series of stores that seem to be connected, Advance Auto Parts, Kragen, and PartsAmerica. They can also be found and ordered online, if a store is not nearby, at partsamerica.com. There are also applications for many other vehicles, EEKs included, if stronger springs are desired.

The springs are very inexpensive. I paid about $45 for mine (for two). Other applications may range up to about $60-$70 or so. I can't really verify price or availability for all applications, but that can be checked online or with one of the stores.

[original writer's name lost, please contact us]; 2002?

Jeremy Andrews wrote: “ I own a 1986 New Yorker with self leveling suspension (ride height sensor sepperate from shocks). When I attempted to buy replacement shocks from Chrysler, I was told that none were available in the entire US dealer network. I was able to replace the factory shocks with aftermarket air shocks. I was even able to reuse the factory air lines from the pump. I simply cut off the factory connectors at the ends of the hoses and used the compression fittings that came with the aftermarket shocks. This was a very simple opperation, and works just like stock. This should work on all self leveling cars with the leveling sensor separate from the shocks.”

I have a 1986 Chrysler New Yorker with the optional load level suspension. I am not sure what other Dodge, Plymouth, and Chrysler K based vehicles [EEKs] this might also be found on, but it seems most common on the E-bodies as far as I am aware. In any event, the rear shocks have needed replacement for at least a year. Finally being tired of the continual whiplash while travelling the frost heaved byways of Saskatoon, Saskatchewan, the time was ripe for replacement.

The first thing to be aware of is that there are no aftermarket replacements for the air shocks on load level equipped New Yorkers. The air shocks are a dealer only item and only come with a one year warranty. Strangely enough if you want to ditch the air shocks you can buy Mopar rear shocks for non load level equipped New Yorkers for about 1/2 the cost and they have a lifetime warranty. Go figure.

It's important to determine if your air compressor is still working. Frankly if mine had not been still serviceable, I would have simply bought non air shocks instead. The compressor is worth about $300 CDN I was told, which would have made it cost prohibitive on this 15 year old vehicle. The steady buzzing from the right rear quarter panel [where the compressor resides] told me that it was still going strong. Pumping the remains of the shock fluid past their blown seals onto my driveway.

The next thing to know is that the Haynes manual that I had [and I suspect most of you out there use] does not cover shock replacement for load level equipped cars. Quoth Haynes, "Servicing this system is beyond the scope of the average home mechanic."

Undismayed, and assuming that I am an above average home mechanic, I went down to the local dealer and ordered two of part number 04420302 [Does anyone really need to be told to replace shocks in pairs? I thought not.] They are now a special order item, but were ready for me to pick up in 3 days. I buy ALL my parts from the local dealer, for which they reward me with a 15% discount so the total tab for both units, tax included was $141 CDN. Not too bad I figured.

The friendly parts guy [really!] warned me that he did not stock the air line fittings that went into the shocks [although they are available] and that I should be "really gentle" pulling the old fittings off. As we shall see, this was the least of my problems.

Once home, I examined the shocks. They look pretty ordinary with the exception that there is a bung welded on the side near the top which accepts the air line. The top and bottom of the shock body are also sealed with a thick rubber boot which is clamped in place and hides the pretty chrome shaft which you would ordinarily be able to see. I assume this is to contain the air pressure. Other than that pretty straightforward.

So with trusty wrenches in hand, I jacked up the car, put jack stands underneath [you only have to attempt to bench press a car once to make you a believer in doing this], pulled the wheels and started to spin wrenches. The top shock bolt is 15MM on either end and is easily accessible. Mine weren't even seized. "Not for home mechanics" indeed! I sneered in derision. For a while anyway.

The air lines are neoprene and are covered with a rubber boot which is itself captured with a wire clamp on the shock bung. Once the clamp and boot are removed, the air lines have a flare not unlike a brake line where they enter the shock. Behind this are two rubber o-rings which are loose on the air line. Both of mine came out with a minimum of effort. After the parts man's warning, I was very careful removing them. Ok, Ok, so on the drivers side, the o-rings were stuck in the shock bung tighter than a ... well use your imagination. No amount of tugging would remove them. I ended up hacksawing the shock bung off and using one of my wife's fondue forks [SHHHHHH!] to push the fittings out the other side. Undamaged, I hope. I mean the fitting, not the fondue fork.

So far so good and I proceeded to remove the lower shock bolts. The bolt in question is also 15MM so I didn't even have to change sockets. I laughed. I was going to be done in less than 15 minutes. Ha, Ha! It was at this point that the Shock Changing Gods stopped smiling.

Sure, it looks straightforward enough. On either side though, you have to unscrew the bolt from the back [behind the shock]. The nut on the end of the bolt [you know, on the side easily accessible to you] is a captured 18MM welded to the shock bracket. You have to slip your socket wrench onto the bolt head on the back. Being exposed to water, snow, salt and god knows what else by continual wheel splash means that after 15 years, the bolt and nut are very good friends. They don't take kindly to anyone coming along and disturbing their relationship. No sirree. When someone does, they fight back. I have the knuckle scars to prove it.

That you can only turn your socket handle 1 possibly 2 clicks at a time means that you will be turning the bolt 1/64th of a revolution at a time, for a very long time. To make it more sporting you also need to use a socket extension. It took me an hour to remove two bolts.

On the right side of the car access is restricted by the gas tank and panhard rod. As you will discover should you attempt this yourself, it is the easy side.

On the left side, you must also contend with the exhaust system in your way. Which hopefully is cold by the time you work in its proximity.

Mine wasn't.

In removing the left side lower shock bolt I chewed the head of it off so that it now had a nice wind cheating aero look to it. Very fashionable but not promising for reinstallation. Down to the dealer for another one. Hey guess what, no stock on the lower shock bolt. Luckily for me, the parts chap knew his stuff and quickly found one from a Caravan which would work. A quick comparo to the old one showed that the Caravan bolt was only about 1/4 inch longer so $4 changed hands and back home I went.

Put the new shocks in, screwed the top bolts in first, and then the bottoms. For some reason, the bottom bolts, which had caused so much grief, were much easier to screw in than take out. I took the precaution of greasing them with lithium so that some mechanic [probably me] in the future will be thanking me. Reinstalling the air line consisted of pushing the end of the neoprene line and the 2 o-rings [per side] into the shock bung [there has got to be a better name for this] and covering them up with the rubber boot. Clipped the wire retainer over the boot [being careful to keep the line bottomed in the bung] and that was that.

If you had to remove a lot of the line from the car [say for example... so that you could hold the shock between your feet while you hacksawed the bung and portions of your left hand off] be careful to clip it back out of harm's way so that it does not foul the suspension.

Not really complicated, but it did take me about 4 hours from start to finish. If I had it to do again, I would:

  • Pay someone else to do it. Except of course that I am too cheap to seriously consider this.
  • Use air tools. Same excuse as above. Seriously though, if you have access to an air compressor and an air wrench, such a set up would have made the whole exercise child's play. Assuming you give such things to your children to use as toys.....
  • Buy replacement bolts along with the shocks. At least for the lower bolts. I know, it's another $4 per side but at least then when you chew them up removing them [and you will my friend, you will....] you can just screw in new ones.
  • Also I would buy new air lines at the shock end. I got away without needing them [I think, I can't see any leaks] but they are only about $5 CDN per side [so sayeth the parts guy] and for that price, it would be foolish to not have them on hand.

And I was done. Wet and bleeding but happy, I took the car out on a test drive. Wonderful! No longer reminiscent of the 50 cent ride-em horsie at Safeway, the vehicle soaked up bumps like it was new. Very cool to load the trunk with groceries [every test drive has to end somewhere], start the car, and feel the rear pump up to level again.

Except that now by comparison the front struts feel kinda mushy....sigh.

If you'd like instructions on another type of repair, click here.

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