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Discussion Starter #1
Hello all,

I have a 2003 SL500 and I am having a suspension issue I can't figure out.

When I bought the car a year ago, they said the ball joint that is part of the front right strut was bad. It was a small dealer (not an MB dealer) and they said they'd fix it. They ordered a USED strut from a wrecking yard (probably not the best idea) and replaced the strut.

Now a year later, everything was fine until next week. About a week or two ago, the car started to make "arthritis" type cracking noises from the front right. Sounds like a ball join/strut mount/control arm type of noise.

I should point out I did a FULL flush of the ABC system 2 months ago. Fluid was black and is now really nice and clean. Assume the fluid in the system was 10 years old it was so bad.

So there's the cracking noise when you first back out of the garage in the morning, hit a big pothole, or make a sharp turn at speed (ie. U-turn)

Last Friday I drove the car and then parked it for the weekend. Monday AM I had the "STOP! Car too low!" in RED letters so I pushed the 'raise' button and then lowered it, and everything was fine. I did see the front of the car raise up.

Now every day when I start the car, I see the front right raise up about an inch as I back out of the garage. It's like the front right tire is in a very small pothole and I'm driving out of it as I back up.

Car drives fine, no problems otherwise. You wouldn't know other than the occasional cracking noise + the front right lowering overnight.

How do I know if this is a valve block or a strut problem??? I will look at the strut tonight and check the fluid level, but I know for sure there isn't any fluid on the ground. The underbody cover on the car was missing (the one under the engine) so I know it isn't pooling up there either.

If I check the strut and see it wet, I'll order another one. But what if it's dry... how do I know if I have a bad valve block?

I'm 90% ready to just order another strut because I'm pretty sure it will fix the problem by putting a new Arnott strut in rather than the crappy one that's there, but I don't want to spend $700 and then find out the valve block was bad.

Suspicious of that strut because I think it's 10yrs old and sat in a junkyard for a year too. I'm pretty sure it bought me another year and then just wore out.

Any thoughts?
 

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Discussion Starter #2
Now that I have read through a bunch of threads, I'm starting to think it might be the valve block and not the strut.

System runs fine once I start driving, so I'm thinking it's not an external leak. I would think if the strut leaked down so the car dropped 1/2" or 1" every day, I'd for sure see a puddle of fluid. Especially over the weekend when I got the red ABC warning message.. for sure there should be a leak, right?

Now leaning towards cleaning the ABC valve block (see the "ABC valve cleaning DIY" post in this forum) if the strut doesn't have any obviously visible leaks.

Just wondering why the cracking noise started all of a sudden.. that seems related to neither the strut nor the valve block... unless maybe the strut ball joint went bad and has somehow caused the strut to go bad with it (yet not leak?!?)
 

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216 with everything. 2002 SL500 with everything. 2009 SL500 with everything.
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Yes the sinking is more likely to be the valve block, as you say the strut cannot really sink without loosing fluid
 

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Discussion Starter #4
Update

Last weekend when the car sank, it had been parked for 2 days.

I left it for 3 days this weekend to see what would happen.

This time there was NO message (white or red) saying there was an ABC error. Car started up and drove as normal.

Although I still notice every time I park at least overnight, the front does drop a little lower. When I back out of the garage, you can see the front raise a little bit (maybe 1/2"? 1"?)

And I measured it last night with my fingers, and both fenders seem to have the same gap above the tire. It doesn't look like the R side is sinking .. I think the whole front is dropping.

So I will look at the strut for leaks, but I'm 99% sure now that the valve block is the problem.

I only drive the car in the summer so I hate to take it apart during 'prime season'. I'll drive it till Sep then try cleaning the valve blocks as someone else here on the forums did. Hopefully that solves it!
 

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I have a related issue but mine just drop the front driver site only when is park overnight, there is no fluid on the floor or wet strut. If possible that the valve block is loosing fluid pressure internally on just one strut? I see related related issues but the car drop all front or all rear. Car drive perfect and maintain exact level when is running, just happen when park for hour over 5 hours.

Thank you for your reply.
 

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Discussion Starter #6
That seems weird.. I thought the valve block would lower the entire front, not just one side.

You may have some sort of internal leak in your strut. If the other strut is for sure staying up all night, I'd replace the strut that is sinking. I think it is bad.

As a quick update for everyone on my situation, I have decided to try rodeoing the car. When I did the flush, I didn't have my DAS laptop, so I had to push the 'raise' button a few times to flush it. Now that I think about it, I guess I did NOT flush the valve blocks by doing this!! (correct me if I'm wrong)

I am going to try these things in the following order:
1. Rodeo the car. I figure this might clean up the valve blocks and get the deposits removed so they seal properly. Fluid and filter is only 2 months old. If the filter or the fluid looks dirty after the rodeo, I'll order new and replace.

2. Clean valve block. My next step would be to try the DIY and clean the valve block.

3. Replace valve block.

I have found a reasonably priced 'rebuilt' (reasonbly priced = less than $1200 for a new one :). So I may order it, swap it with mine, then try to clean mine and hang on to it as a spare. I really can't take off the valve block and ship it in, because I only drive the car in the summer and it's already Mid-Aug. I have no ability to take it off at the place where I store the car in winters. So I figure I'll just do a swap and then clean up the old one.


But hopefully the rodeo removes all the crud and fixes it !
 

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The creaking noise that you had mentioned in your original post is not related to the strut at all. If you can take a look at the front arm thrusters (control arm) bushings. It appears that your bushings have a crack in them and they make the squeaking sound. The raising a lowering of your car is related to the control valve. As you mentioned, there is a great article in this forum on how to take the valve out and clean it and that should help with that.

Good luck and keep us posted on your findings.
 

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Discussion Starter #8
Update

I have driven the car about 3000km (1800 miles) since I did the full flush and filter replacement earlier in the summer, and the "sinking" after parking has been getting worse. Now it happens pretty much every night and can even start to occur after just a few hours of being parked.

I ran the rodeo program on my DAS laptop last night.

The car didn't sink at all overnight! I always watch the front right corner of my hood as I first back up, and it usually raises what looks to be an inch or so. It didn't move as I backed out of the garage!

I was expecting the "ABC Stop Car Too Low" message in red that I get almost every day. Nothing at all. And no raising of the front end.

I only ran the rodeo once (approx 15 mins). I think for good measure I'm going to now change the fluid and filter (remember it was totally black when I changed it the first time) and then run the rodeo once again. It's probably well worth the $150 to do it and ensure everything is nice and clean inside the system!

One concern: the pressure fluctuated (during rodeo) between 57 and 65 bar. From everything I have read, the pump is supposed to run at 180 bar.. is it supposed to be that high even at idle while doing a rodeo? If so my pump is WAY low.

The weird thing is the car raises quickly and operates normally... so how can the pressure be so low yet everything works? Is my pump on the way to impending death? :(
 

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I have driven the car about 3000km (1800 miles) since I did the full flush and filter replacement earlier in the summer, and the "sinking" after parking has been getting worse. Now it happens pretty much every night and can even start to occur after just a few hours of being parked.

I ran the rodeo program on my DAS laptop last night.

The car didn't sink at all overnight! I always watch the front right corner of my hood as I first back up, and it usually raises what looks to be an inch or so. It didn't move as I backed out of the garage!

I was expecting the "ABC Stop Car Too Low" message in red that I get almost every day. Nothing at all. And no raising of the front end.

I only ran the rodeo once (approx 15 mins). I think for good measure I'm going to now change the fluid and filter (remember it was totally black when I changed it the first time) and then run the rodeo once again. It's probably well worth the $150 to do it and ensure everything is nice and clean inside the system!

One concern: the pressure fluctuated (during rodeo) between 57 and 65 bar. From everything I have read, the pump is supposed to run at 180 bar.. is it supposed to be that high even at idle while doing a rodeo? If so my pump is WAY low.

The weird thing is the car raises quickly and operates normally... so how can the pressure be so low yet everything works? Is my pump on the way to impending death? :(

Your pump is weak, it should be 180 to 200 bar and during Rodeo may drop as low as 85+. But your real problem is sticking valves, the fluid must be ultra clean and a flush with circular rodeo is the real answer.
 

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