bugnuker

Hello,

I'm posting here to see if any of this make sense to anyone or if anyone has had similar issues.

I have a 2007 CLS550. I've replace both front shocks/struts and I've replace both rear air strut with arnott replacements. One of my arnott replacements died after 18 months (front passenger), and was replaced under warranty.

Everything was driving pretty good, but I started to notice some "boaty" feel to the car. I've had the car in the shop at least three times for this. Each time, I'm told a lower control arm, or a ball joint, or the alignment is the issue. I've replaced all arms, ball joints, thrust arms, and had the car aligned, but yet, the boat like feel (rocking) is still there.

All shops hook up the computer and say the computer tells them the ride height is correct. Diagnostics show everything is fine on the computer.

Frustration is not the right word. I just want the awesome ride this car used to have back. I try to do some of my own tests and I start to notice it getting worse and worse. Finally, I think I know it is to do with the driver front, or passenger rear, that diagonal line. I then notice the passenger rear is about 1 inch higher than the driver rear.

I take it back in to the shop and they check it out. At this time, I learn some new things. I learn the computer only allows for three areas of calibration for ride height. You have driver front, passenger front, and one setting for rear. There is no setting for individual sides on the rear.

I then learn that arnott makes the replacement air bag in the rear, but not the shock. That is from Bilstein and is a separate part. a 650.00 part.

http://www.oreillyauto.com/site/c/de...0077&ppt=C0035

The shop takes the car on the lift and does some diagnostics. They think the airbag, arnott strut on the passenger rear is bad. I've replaced this before, but hopefully it will be replaced again under warranty. I've never replaced the air shocks it seems, only the air bags from arnott. I had no idea there were two separate parts, one not from arnott. My car has 150k miles on it, and those air shocks have never been replaced.

Any input? Anyone else have similar issues? Anyone know more about this? Why are there air shocks and air bags? I assume the air shock controls the dampening? and the air bag controls the ride height? I dunno. I thought it was all the same unit like the front. One contained part.

I've put a good amount of money into this suspension. I know I can convert - I don't want to. I'd like to understand and get it fixed. When it works, it is a solid ride and very capable, I want that back.

I would love to learn anything you guys have to tell me. I love this car. I want to keep it for several more years. I just want to understand it

bugnuker

Update: Got the car back from the shop today. I asked to only change the air spring on the passenger side, in hopes this will even out the ride height.

The car feels better, but I need more driving time to know for sure. I need to take it on my usual daily and I'll know, but as of right now, the ride height is even in the back and it does feel better.

The shop gave me the old spring. Said there was no core....

Anyways, so far, that is what I know. I am going to try and contact Arnott again and see if they will take the shock and see if they can find it was faulty. Maybe I can get some money back via the lifetime warranty...

This would make two Arnott failures in my car. This is un-heard of from what I know and have been told.

bugnuker

Back to old habits it seems.

The car was level for a few days, but now I'm having the same issue. The car wobbles, and just sucks to drive.

I've decided to go high tech on this battle. I'm a computer guy so I figured I should be able to at least get some data on this issue.

The new phones of today are loaded with sensors that most don't know about.

I installed a few apps that can use all of these sensors and they tell me a great deal about what is happening.

First, level sensor. You can download tons of level apps for you phone. I got one, and found that on good days, the car is only -0.4 degrees out of level. On bad days, the car is +1.8 degrees out of level. Holy ****!

That is really all there is to say - I mean, if the car is not level, and the air spring is giving 1 more inch of ride height on that one side, I'm guessing this is where my wobble is coming from - more play room for the shock to move, thus creating un-even shock correction. When I find those overpasses with un-even pavement, and I seem to hit them at the right time, the resonance makes the car feel like I'm on a boat and you get literally thrown around in the car. It is un-real. It is just horrible.

Other apps I downloaded also let you see the wobble when driving down the road. They use the sensors and build a graph using accelometers, etc. In this data, the graph shows higher peaks on the passenger side of the car, meaning the car is traveling more on that side than the driver.

I've talked to some guys around the internet, and the next possible thing to check is the leveling sensor on the rear. The rear only has one leveling sensor. I talked to my shop about that and he does not believe that is the problem. I got a little terse and just asked for the price anyways. He seems to think there is a valve getting stuck somewhere, preventing the sir spring from fulling deflating. He said he wants a few days to talk to some people and see what they think. Anyways... the hunt continues.

This would mean the air spring was never faulty in the first place!

Holy hell.