SL/R230: Front suspension going up and down, while driving
10-10-2018, 06:08 PM
#1
Member
Thread Starter
Front suspension going up and down, while driving
Looks like the time to deal with the first ABC suspension problem has come for me.
My 2003 SL55 with 130k+ miles has been sagging over night for the last few weeks. Some morning not so much, some mornings i will get a red ABC warning light, very random. If i get a warning light, I press the suspension level button and the warning goes away. Car drives fine.
I have also measured the distance from fender to floor in the mornings, on all 4 corners, and the driver side, front corner is always lower, by about 1in or less. Clearly - not normal. We're talking 24-48hrs of the car being parked. If i leave it parked on the highest setting, it obviously takes a few days before it sags and i get a warning light.
The struts were replaced about 20k miles ago with Arnott units. Many of the hydraulic lines were also replaced, along with the pump. No leaks. Fluid is very clean, with almost no color. Filter is new. No warning lights, except first thing in the morning when one corner is too low.
Well, this morning i took the car for a quick spin on a twisty road. It was only a 5 min drive or so. When i stopped at a light i realized that the front of the car is going up and down, from left to right, on its own. It felt like the front was gently bouncing left to right, up-down-up-down.
It was doing it even when the car was in motion.
I tried to raise it up and bring it down a few times, but it was not very smooth. One corner will go up, then the other, then one will go down on its own, then it will try to go up on its own, etc, etc....almost like the system is trying to compensate for an internal issue/leak.
There were NO warning lights at all during this whole time. Just a very unpleasant up and down behavior.
I took the car home, parked it in the garage, raised it at the highest position and so far, 2 hrs later, it is still raised, but one front corner is a bit higher than the other. Not good.
Here a few questions:
Based on the above, would you say that my front valve block is the reason for this behavior? Could there be any other component that i am overlooking?
If it's the valve block, i am planning to order a set of seals and i will refresh/rebuild it. I watched a bunch of videos, seems to be a DIY job. I have done plenty of projects on my car, i *should* be OK to tackle this on my own as well.
When i disconnect all the lines from the valve block, should i expect any high pressure fluid to start leaking? If yes, any way to relieve the pressure?
Should i be concerned with the pressure reservoir (bulb) when i disconnect it?
Since the lines will be disconnected for some time, what is the best way to cap/close them while i am working on the block?? I don't want to loose all the fluid.
Once i put everything together, assuming that i kept everything clean the whole time, is a full fluid flush absolutely mandatory?
Any other tips/tricks/warnings?
Thank you!
My 2003 SL55 with 130k+ miles has been sagging over night for the last few weeks. Some morning not so much, some mornings i will get a red ABC warning light, very random. If i get a warning light, I press the suspension level button and the warning goes away. Car drives fine.
I have also measured the distance from fender to floor in the mornings, on all 4 corners, and the driver side, front corner is always lower, by about 1in or less. Clearly - not normal. We're talking 24-48hrs of the car being parked. If i leave it parked on the highest setting, it obviously takes a few days before it sags and i get a warning light.
The struts were replaced about 20k miles ago with Arnott units. Many of the hydraulic lines were also replaced, along with the pump. No leaks. Fluid is very clean, with almost no color. Filter is new. No warning lights, except first thing in the morning when one corner is too low.
Well, this morning i took the car for a quick spin on a twisty road. It was only a 5 min drive or so. When i stopped at a light i realized that the front of the car is going up and down, from left to right, on its own. It felt like the front was gently bouncing left to right, up-down-up-down.
It was doing it even when the car was in motion.
I tried to raise it up and bring it down a few times, but it was not very smooth. One corner will go up, then the other, then one will go down on its own, then it will try to go up on its own, etc, etc....almost like the system is trying to compensate for an internal issue/leak.
There were NO warning lights at all during this whole time. Just a very unpleasant up and down behavior.
I took the car home, parked it in the garage, raised it at the highest position and so far, 2 hrs later, it is still raised, but one front corner is a bit higher than the other. Not good.
Here a few questions:
Based on the above, would you say that my front valve block is the reason for this behavior? Could there be any other component that i am overlooking?
If it's the valve block, i am planning to order a set of seals and i will refresh/rebuild it. I watched a bunch of videos, seems to be a DIY job. I have done plenty of projects on my car, i *should* be OK to tackle this on my own as well.
When i disconnect all the lines from the valve block, should i expect any high pressure fluid to start leaking? If yes, any way to relieve the pressure?
Should i be concerned with the pressure reservoir (bulb) when i disconnect it?
Since the lines will be disconnected for some time, what is the best way to cap/close them while i am working on the block?? I don't want to loose all the fluid.
Once i put everything together, assuming that i kept everything clean the whole time, is a full fluid flush absolutely mandatory?
Any other tips/tricks/warnings?
Thank you!
10-10-2018, 08:28 PM
#2
It definitely sounds like you're having valve block issues based on the "unintended rodeo" that you seem to be getting and the repeated sagging.. If you or a friend has a STAR reader you should hook it up to see what codes are presented that are unrelated to the valves.
Usually people say to flush the fluid just because it's not something that most owners stay on top of. Since yours was flushed recently and still appears to be in good shape, you should be ok with reusing it and topping off whatever happens to leak out.
There are a couple ways to relieve the pressure on the system once you have the car on jack stands. One is to bleed at each strut, but there are also bleeder screws on each valve block which would probably be easier. You shouldn't leak too much fluid during this process, but it you get any dribblers, just zip-tie a plastic bag around the hose end to collect any drips.
Only other thing that comes to mind is to double and triple check your fluid level in the reservoir before starting the car, you may have to manually prime the pump if it goes dry by popping off the serp belt and spinning the pump pulley to get things started. After that do a manual or STAR-initiated rodeo and see if there are any leaks.
Usually people say to flush the fluid just because it's not something that most owners stay on top of. Since yours was flushed recently and still appears to be in good shape, you should be ok with reusing it and topping off whatever happens to leak out.
There are a couple ways to relieve the pressure on the system once you have the car on jack stands. One is to bleed at each strut, but there are also bleeder screws on each valve block which would probably be easier. You shouldn't leak too much fluid during this process, but it you get any dribblers, just zip-tie a plastic bag around the hose end to collect any drips.
Only other thing that comes to mind is to double and triple check your fluid level in the reservoir before starting the car, you may have to manually prime the pump if it goes dry by popping off the serp belt and spinning the pump pulley to get things started. After that do a manual or STAR-initiated rodeo and see if there are any leaks.
10-12-2018, 02:56 AM
#3
Member
Thread Starter
Back to normal
Quick update...
So, while i am waiting for my valve block seal kit to arrive, i decided to scan the car with my iCarsoft MBII. Under the ABC module, there was only one code stored - "Front Left too low".
No other error codes stored.
I started the car, and it was not bouncing up and down anymore. All normal. Like nothing happened yesterday.
I cycled the suspension height settings about 10-12 times....up-down-up-down-up-down, etc
Just to be safe, i decided to check and clean the height sensors on the front. Removed the wheels, cleaned all the accumulated dry mud from the connectors, disconnected the sensor connectors, cleaned with compressed air and electrical connector spray. Visually everything looks great.
Took the car for a 30 min test drive. I drove on the same curvy road, i took it over some very bumpy roads, on the freeway, etc.... suspension works like new. No issues. No dancing up and down. No warning lights. I can raise and lower the car if i want.
I am really not sure how to interpret all of this. Happy that things are back to normal, but i kind of want to know why the ABC went crazy yesterday. I did not fix much, other than 10-12 up and down cycles and cleaned the height sensor connectors.
So, while i am waiting for my valve block seal kit to arrive, i decided to scan the car with my iCarsoft MBII. Under the ABC module, there was only one code stored - "Front Left too low".
No other error codes stored.
I started the car, and it was not bouncing up and down anymore. All normal. Like nothing happened yesterday.
I cycled the suspension height settings about 10-12 times....up-down-up-down-up-down, etc
Just to be safe, i decided to check and clean the height sensors on the front. Removed the wheels, cleaned all the accumulated dry mud from the connectors, disconnected the sensor connectors, cleaned with compressed air and electrical connector spray. Visually everything looks great.
Took the car for a 30 min test drive. I drove on the same curvy road, i took it over some very bumpy roads, on the freeway, etc.... suspension works like new. No issues. No dancing up and down. No warning lights. I can raise and lower the car if i want.
I am really not sure how to interpret all of this. Happy that things are back to normal, but i kind of want to know why the ABC went crazy yesterday. I did not fix much, other than 10-12 up and down cycles and cleaned the height sensor connectors.
10-12-2018, 07:19 AM
#4
Senior Member
If it's the valve block, i am planning to order a set of seals and i will refresh/rebuild it. I watched a bunch of videos, seems to be a DIY job. I have done plenty of projects on my car, i *should* be OK to tackle this on my own as well.
When i disconnect all the lines from the valve block, should i expect any high pressure fluid to start leaking? If yes, any way to relieve the pressure?
Should i be concerned with the pressure reservoir (bulb) when i disconnect it?
When i disconnect all the lines from the valve block, should i expect any high pressure fluid to start leaking? If yes, any way to relieve the pressure?
Should i be concerned with the pressure reservoir (bulb) when i disconnect it?
I did my front valve refresh at 113K miles 2 years ago because I was getting a red ABC warning every couple of months. I scanned with SDS and found left front strut code too low. I only did the front valve block but bought enough o-rings to the do the rear but as of yet haven't done it. I have 130K miles now.
This is not a difficult job for the average MB DIYer and is one of the more satisfying jobs I have done on my cars. There are plenty of posts to refer to for guidance. I got stuck on the valve removal, I can't remember how much to turn them to get them out but I believe 45° not 90° . What ever you do, don't pry on them. They will slide out with hand pressure.
Post back your success story.
Good luck,
Bob
As an aside, if you haven't already ordered your o-rings, I purchased mine from oringsandmore.com
Last edited by mercy-me; 10-12-2018 at 10:29 AM. Reason: add o-rings
