I have replaced the rear shocks (2003 R230 SL500) following the Arnott and StrutMasters videos and all the comments and advice from the bulletin boards. In the process I have discovered that we have been doing it all WRONG. The videos can be watched to see all the steps we should NOT be doing, including removal of trunk carpeting, removal of the brake caliper, and most importantly removal of bolts and arm behind the wheel hub and fighting with pry bars to lower the arm out of the hub, and to put the arm back into the hub and into the rubber bushing which seems impossible to align.

Instead, the strut should be removed FROM THE OPPOSITE END OF THE ARM as follows:

1) With the car on jack stands and wheel removed release the hydraulic pressure (if any) at the bleed nipple, disconnect the oil line at the strut by pulling by hand the quick connect (cover the ends to avoid contamination), disconnect the height sensor at the lower arm supporting the strut with 10mm socket and 8 mm spanner

2) Remove 3 bolts: the bolt attaching bottom of the strut to the arm, bolt connecting the stabilizer bar (top rear of the suspension sideways bar) to the wheel hub, and the bolt attaching the arm to the subframe. You are removing the stabilizer bar bolt only so you can push on the bar by hand to clear the arm to subframe bolt for withdrawal. It’s helpful to support the arm with a small hydraulic jack to release any pressure on the bolts when withdrawing them and later for reassembly to re-align them.

3) Pull the corner of the carpet in the trunk above the strut by hand to exposure top of the strut. Disconnect electrical connector and remove 2 bolts holding the strut. When finishing bolt removal with one hand, hold the strut with the other hand so it does not just drop on the floor but is lowered gently. That’s it.

Reasembly is the reverse. Note how easily and smoothly the arm to subframe bushing is aligned for the bolt with a small jack (up/down) and pushing on the brake rotor (in/out). I also apply blue LockTite on all bolts. Torque to specs.

With everything prepared and wheel removed the strut removal takes literally minutes and requires no physical strength (if bolts are frozen there is enough room for impact wrenches or extension handles). Of course use at your own risk and consult a professional if you don’t normally work on cars.

 

Here is a photo of the arm already dropped and strut removed (ignore missing brake disk removed for other reasons)



This is the stabilizer bar (left) disconnected at the hub (right)



This is the carpet pulled back to show the top of the strut.

 

Photos of the strut removal are for the rear right side, photo of the trunk carpet is for rear left strut

 

Wow! I love these types of posts

 

Thank you for that post. I will try doing that on the left side.

 

thats what makes these forum so good to use
thank you
peter

 

BTW, if you just pull the carpet corners in the trunk instead of removing the carpets completely you will likely break the carpet plastic edges around the mounting points of the trunk lid arms. To avoid that it may be good to un-glue/remove and re-glue the edge plastics later, or cut them in a couple of places to introduce a clean folding spots (or of course spend the time removing the carpets if the edge breaking is a concern).

 

I've been thinking about that method while laying under my SL and reassembling the side I had taken apart the "Arnott way". Does anybody know weather or not the lower arm is (or has to be) mounted with "pre-tension"? (I don't know the correct english term for that...)
Because if it is, then the new method presented here wouldn't be optimal... Or more precisely: You would have to cope with that in some way.

 

Very interesting and I want to make sure I have this right- so another words, drop the inner part of the control arm, where under the "other" methods, this side was used as a pivot point to lower the arm and drop the strut out? This allows the hub side to remain substantially assembled.

Related - two things I'm struggling with. My drivers rear strut is dripping oil at this point, so I need to replace. My passenger rear is completely dry. Both are original parts. (1) If I go with Arnott, do I really need to change both sides? Based on my understanding, if I only want to replace one side, I need to use a MB strut, which essentially is the same cost as 2 Arnott struts. And I've heard Arnott struts tend to ride a little firmer? (2) Has anyone replaced the struts and NOT have to had performed a Rodeo? When my car has been in storage, it's dropped to the point where I'd imagine a new strut would be upon initial installation. Upon start-up, the car levels right off and all's good. Wouldn't the new strut just "fill" back up and level off, similarly? Where I could raise/lower the car (similar to what I did when I flushed the system not too long ago), and monitor fluid level?

Thanks

 

Yes, you are correct about the sides. Leave the wheel/hub side untouched, even without removing the brake caliper or anything. Instead of fighting with several hard to access bolts and pushing the arm in/out of the hub, remove the single bolt on the other side.

I will let others comment on the remaining questions. .. ...

 

i replaced one strut with the Arnott as I recall. I have not notice any issues and I did not perform the rodeo procedure.

 

Thank you for the post, I added the links of Front and Rear ABC Struts Arnott installation videos,

Front: https://www.youtube.com/watch?v=Q4t-...ature=youtu.be
Rear: https://www.youtube.com/watch?v=rdth...ature=youtu.be

 

For the replacement of one versus a pair of the struts with Arnott it may also be good to get confirmation from Arnott regarding their recommendation.

 

George933 and anyone else with knowledge of strut and accumulator replacement ect.

I have an R231 but, I'm helping a buddy with his R230 ABC strut and accumulator replacements.

Great tutorial on rear strut removal and following Arnott video seems front easy as well but, I do have a question relating to amount of system fluid loss per strut............................................. and best method for replacement of fluid when doing 1 or more than 1 strut....................................also is it necessary to have a "star" system to replace the struts and fluid..........................................?

Few more question relative to the accumulators....is their replacement as easy as the struts............................................ .., anything to watch for..........................................., should we replace the pulsation damper as well as the F & R accumulator...................................... and again question regarding fluid replacement................................. and OK to do without a "Star".............................?

Maybe one more question: While we at it should we replace any hydraulic line or lines that are most likely to fail.................?

Nothing that would indicate the pump or valve blocks are an issue so plan to leave them alone.

Final question: Of course we will do a filter and fluid change with the new 10 micron filter; thinking of cleaning out the canister with a turkey baster, installing a new filter and fluid doing body movements up and down and riding the car for a number of miles then another clean-out of the canister and new filter and new fluid........sound like good way to go......?

Appreciate any help with my questions above.

THANKS, Steve

 

For the fluid just keep adding with the engine running until the right level is reached. The dipstick shows levels with and without the engine running. But since the pump is below the reservoir and all the hydraulic circuitry is after the pump, even if you drain all the fluid from all the struts/hoses the level in the reservoir will almost not change and will be showing full (the stationary pump blocks it from going down, at least in my car). Once you start the engine the fluid will disappear from the reservoir into the plumbing.

Make sure to wear eye protection and disposable clothes as you may get fluid sprayed even if you think the pressure has been released (ask me how I know).

STAR is for the rodeo and such but I think the system should bleed itself after some driving and suspension up/downs (keep checking the fluid).

I don't know about the accumulators on this car but I changed them on a different Mercedes (wagon) and it was quite easy. You know they are bad if the ride becomes bouncy and fluid level goes down - gas inside the accumulators gets replaced with the fluid and does not absorb shocks.

For hoses - if you want to be safe change them ALL! No kidding, I recently had a hose rapture on my car while driving, like I hear a gun shot, the car drops down by a few inches on one side and immediately I become stranded (at night in my case) - the car becomes undriveable. That did it for me and I threw out the ABC and installed coilovers - will write up on that soon.

 

Plus the struts replacement could get complicated if some bolts turn out to be frozen - happened to me and even a high power impact wrench (double torque of the regular ones) and soaking for days did not work on one (luckily there was a work around by removing other bolts). So it could all go quickly, but you could get stuck as well, specially in MA where parts could get rusty

 

And if you are doing the fluid change read up on the procedure, including this thread (has ideas on how to keep the reservoir full when starting the engine and not allowing the pump to run dry/cause priming problems)

https://mbworld.org/forums/m275-v12-...on-thread.html

 

Thanks for sharing. It was my understanding that Arnott uses Mercedes OE struts as their base for rebuilding, so I had thought no harm in replacing only one.

 

Hey all happy holidays.

Had a successful day replacing my drivers side rear strut using this "new" (er) method of removing the inner control arm bolt. Overall it wasn't bad with An extra set of hands to maneuver a second jack under the control arm at certain times. Luckily my car is rust free- every bolt loosened right up, even the exhaust hangers. I had to drop the exhaust at three points to clear removal of the inner control arm bolt towards the rear. The quick disconnect was a little tricky- just had to work some WD40 into it to get it to fully release.

Buttoned her back up, topped off the ABC reservoir, started the car and raised and lowered it half dozen times. No leaks, no lights. Haven't driven her yet but hopefully this indicates I'm in good shape.

This was always a job I've been intimidated by, and I'm very experienced w car repairs. I'm very happy with how the process went. Got an Arnott strut from summit for a good price too.

 

This was my old OEM strut. Leaky at bottom but never fully gave out. Was dripping from the control arm though.

 

Jay04SL Congrats on the job well done!

But I'm surprised with your comment: "I had to drop the exhaust at three points to clear removal of the inner control arm bolt towards the rear." Sorry if that point of my instructions was not clear, but I never had to touch the exhaust - if we are talking about the same bolt, it came out easily after:
1) Disconnecting the stabilizer bar as shown on the photo titled "This is the stabilizer bar (left) disconnected at the hub (right)" above
2) Pushing the stabilizer bar down by hand from the outer side, as it pivots on the inner (at the car center) side and clears the arm bolt for withdrawal

There should only be a total of 5 nuts to remove - 2 for the suspension and 3 (one at the bottom and two at the top) for the strut itself. All 5 easy to access and easy to undo unless the car is rusty. Or perhaps your car is different than mine 2003 SL500? In any case the job is completed so in one sense it does not matter for this case, but for the benefit of others and to keep it as simple as possible - could you please elaborate exactly why you had to do it? Thanks!

 

BTW, if someone decides to give up on the ABC and install coilovers instead, here is a thread where I have documented the complete process (parts needed and steps: struts replacement, looping back the ABC pump and re-configuring the electronics for ABC-free system).

All the parts in total for the complete conversion, including top of the line, multi-adjustable coil over struts, cost $39.00 (thirty nine US dollars, this is not a joke or a miss-print and includes parts and all the shipping etc costs in continental US - it's $39.00). Plus the labor and access to a STAR system or similar for electronics re-configuration. You can also ignore re-configuration, the car drives the same either way, just gives red ABC alarms without reconfiguration. Here are the details, thanks

https://mbworld.org/forums/sl-class-...er-struts.html

 

Also if someone is doing this job, please post pictures of the bolts being removed etc to help others who may be planning it. In retrospect when I was doing this job it all seemed obvious, now reading it after a few months without looking at the parts it's not that obvious any more so I wish I would have posted more photos.

 

How hard is it to remove the dust boot from the shock? I have this job on my to do list but to be honest im not looking forward to it. I dont seem to have circlip pliers either.

 

Thanks George! Great question, and I'm happy to clarify. I was wondering as I was under the car whether you mentioned lower the exhaust, as I did not recall you saying. My car is an 04- not sure if that makes a difference. Only thing I'm thinking, is I replaced my drivers side, was yours passenger? Perhaps the run on the passenger side exhaust gave you a touch of extra clearance? On my car, the bolt needs to be removed sliding it towards the back of the car, which directly hit the exhaust pipe. I had about 3/4 of inch of threads remaining in the control arm that I needed to move the pipes slightly to get the bolt to fully be removed. Hopefully that makes sense. I was saying, why couldn't the bolt have been inserted from the front of the car- plenty of room to remove the bolt then. Luckily, I only needed a little play in the pipes to fully remove the bolt.

I know I mentioned, but that quick release was pretty stuck. Luckily after WD, and rotating, it started to slide more and more. You could see the red from the rust when spraying it down. It was equally tricky to re-install. I couldn't get that resolving "click" when re-installing, eventually, I knew it was on there- I was able to push the line in and out and felt the lock.

Happy to answer any other questions. This was a fantastic technique you posted.

Cheers