I would not do it as I'd get the car rolling. I like to get the car going as whole before taking it apart section by section. Chris in Illinois like to do that, that is not my style. It starts to go from a deep-repair to a big restoration job...

Not my style..

Martin

 

Martin:
I've been anxiously waiting for the moment the engine would roar again. I feel I am getting close(r) :smile

I agree that my transmission repair had morphed into something that resembles a "restoration job" but I had to take apart so many things along the way. Not what I intended to do when I wrote the check last February and got the car delivered.

In a way I am glad I did, because I learned a lot and got the chance to replace the engine mounts, idler arm, the flex discs, the prop-shaft center support, etc. I would have never thought about doing those on a car with 50K miles, but they were in a terrible shape.

Just look here:

http://www.benzworld.org/forums/w140-s-class/2577201-mission-creep-m120-owners-please-read.html

and here:

http://www.benzworld.org/forums/w140-s-class/2577073-1404100481-rubber-boot-bearing.html

I will update the threads with more pictures soon.

Steve

PS There will be more "surprises" -- no doubt about it. Who knows what is the condition of the fuel pumps (I have put fuel stabilizer in the tank, hope that my 1+ year old gas has not solidified). Also PSE, tandem pump, etc.... But I'd hate myself if the exhaust system will have to be split again to get the access to the sphere I have right now...

 

A quick check of the hydraulic fluid in the reservoir will tell you alot. If it's black-ish, the accumulators are done. However, I'm with Martin on this one. Leave them for another day.

Good luck

Jayare

 

Thanks. The reason I posted the picture of the accumulator itself is that the fluid did not look fresh.
As you can imagine, a car that has covered ca. 1000 miles in the last 5 years required a lot of catch-up maintenance. All fluids were disgusting, the hydraulic fluid included.

The worst was the A/T fluid of course, which I expected. It had metal particles.
The differential fluid -- OMG. The garage still smells.
The windshield bottle must have been filled with regular water, as there was vegetation growing.
The coolant was terrible too. I wish I had measured the pH. May have been as acidic as vinegar.
Brake fluid is dark. I am guessing never replaced in 23 years and probably has absorbed unknown amount of moisture.

The hydraulic fluid -- it is not amber, but not too bad. There are receipts showing the replacement of the tandem pump in 2007 and 3L of the MB fluid used, so at least we know the system has been dealt with before. But knowing what I now know about the PO, I am 99.9% sure that the spheres have not been replaced.

Thanks for the reply.

Steve

 

Steve

Just make sure you get the ATF out of the system as best you can. The rear rams/shocks are going to hold the most. Probably best to remove them and compress/extend until there is virtually no evidence of the ATF.

Good luck partner

 

Thank you. I'd figured a flush will be required. But should I expect damage to seals, valves?
Also, can compressing/decompressing be done on the car? Raising/lowering RR and LR several times? How about the front?
Or it is best the shocks come out one by one?

I am asking because the engine is still inop, and I am afraid that if I depressurize the system now, it could be several more weeks before I can get it running.

Steve

 

Before you conclude that ATF was put in the SLS reservoir, keep in mind that the correct colorless fluid that goes in there does get brownish colored over years of use. if color is not definitely 'red', I wouldn't think that ATF was put in there. You might want to compare smell of fluid to ATF. The hydraulic fluid starts out colorless & pretty much odorless whereas ATF definitely smells different.

 

Thank you for the suggestion. The camera doesn't do a good job capturing the colors.
The fluid I drained from the reservoir is fresh-looking, cherry-red ATF.

Steve

 

Bummer. You'll either have to take the shocks out to empty them or flush twice probably. Taking shocks out isn't too hard. First see how hard it is to get hydraulic connection loose. Once that's cracked loose, the rest is straightforward.

Even with that, you'll probably need 4 qts of the hydraulic oil.

 

Well, the saga continues...

Removing the shocks was not too bad, as suggested, but once they were out, I found a few other problems.
1. The top mount rattled a bit.
2. The lower bush was gone (see picture).

I read some of your earlier posts on the subject 1403200944.
Agreed, overpriced (for what it is - see picture) and probably over-engineered.

I also saw some of your comments about the front shocks, which cost less (complete unit) than the SLS top mount 1403200944 alone.

Decided to improvise -- bad idea -- got a pair of KYB 553606 shock gas-a-strut shock absorbers for $150 and was hoping to rob them of the mounts and bushes.

Pictures tell all -- while I could have use a saw to cut the stem of the SLS shock to get rid of the damaged bush, doing the same on the standard KYB shock would have been very hard. No stem.
I was hoping to tap the stem and use a thread steel rod to do the swap...ohh well. Ended up doing the mode a kind member from New Zealand posted some time ago -- using the BMW bushing.

As far as the top mount goes -- the swap I had in mind would have worked, except that the front shock mount is not as tall as the rear (please see the picture).
Bummer! Ended up buying two new 1403200944 mounts from MB for over $120 each.

The pair of KYBs 553606 is my basement and I can't use them. My car has ADS and those won't fit. If anyone with a w140 w/o ADS needs new front shocks, please PM me.

Best regards,
Steve

 

Just a suggestion but use Benz hydraulic fluid. It's pricey but so is the suspension system.
Anziani

 

000-989-91-03-10 Hydraulic Oil. About $10/liter.

The Febi stuff cost about the same. I think I actually paid $12/liter for Febi. "Oh well".

 

Steve B,

You say that the bottom bushing is "gone", but it doesn't look that bad in the pic.

Keep in mind that the bottom bushing has a plastic cover on both sides of the middle annular bushing. These thin plastic covers get cracked and funky looking even though the middle annular bushing that provides support for the inner metal tube/bushing is still functional and not loose.

There's big difference between funky appearance and looseness as in the top mount.

If the top mount is wobbly & loose, it will make dull klunking sounds going over the bumps.

If the bottom bushings are not loose, then I would say that the top mounts are the big problem.

The top mount design really is a poor design in the sense that the swaged together 'pod' added lots of extra cost AND incurred inherent flaw of absence of any external means of ensuring preload on the damping rubbers.

I did make a design to change top mount to conventional style mount using the R129 rear shock rubbers. This requires machining a male-female threaded adapter and also an aluminum supporting plate/washer.

If you are a machinist type, I can send you that stuff. Otherwise, the top mounts are ~$96 ea last I checked.

 

Thanks for the feedback, but you probably missed it -- all the work is done already, and I am buttoning it up right now.
New top mounts from Autohausaz
You cannot find anything from a reputable retailer for less than that.

While the lower bushings could have been in worse shape, the plastic seals on both sides were gone. There was plenty of dirt inside already. What you see on the picture is the cleaned up version -- the PO must have placed a huge blob of grease over the bushing to "make it ride quieter"

I did this fix

I am determined not to go back and revisit rear suspension in near future -- everything starting from the tandem pump, lines, accumulator spheres, mounts, bushings, etc. is now cleaned, checked, replaced. System is flushed, used over 6 liters of MB fluid.
Time will tell if I did a good job.

Best regards,
Steve

 

What is the procedure for flushing the ads on a w140? On my r129 you can cycle the height to run the pump, but the 140 doesn't have this capability. My new to me cl600 had all fluids done recently by dealer other than ads, and its not awful but it is dark, and has 55k on it.

Also, haven't looked yet, how accessible are the accumulators in a car that's together?

 

You've seen my posts, right? 600SEC with 52,000 miles.

I am type that sees the glass half-empty. With this disclosure in mind, and with the pictures I provided in this thread, you probably will understand why I will say -- oohh myyy! You're are in for some serious work in the back.

A new thread with lots of pictures is coming up. Any part I touched needed attention. The accumulators will require you to remove the rear section of the exhaust and a bunch of other things.

My advise will be to remove the shocks too, and empty the crude from them. Fill and drain several times. You will be, most likely, disgusted from what comes out.

Good luck. You are not far away from me, perhaps we can meet up someday for a coffee/beer and share thoughts on our c140s....

Steve

 

Yes-will have to run to the Newark Iron Hill or somewhere...

The rear accumulators on the r129 are no piece of cake. Pass side easy, but drivers side above the exhaust. Doable with it in place, but barely-you could only move the flare wrench a quarter turn at a time.

 

What are actually the accumulators and when to replace...?

I had some time between two kid's B-day parties this weekend to dig a bit deeper on the subject of SLS system accumulators (aka Pressure Spheres, Nitrogen Spheres, Spring Actuators)

The reason I decided to revisit this old subject are two comments posted last week. One lister claimed that a certain amount of $$$ spent on expensive SLS shocks and springs restores the silky smooth ride in the back, but when asked about accumulators, the response was:

Didn't count that in cause I didn't have that problem, so never looked into it.

In another concurrent thread on related subject, Martin (aka MAVA) advised:

You need to change the hydraulic fluid like every 40k to 50k miles, and accumulators have to be changed every 80k to 100k.

to which the response was "Martin, those are just recommended replacement times, you don't "need" to replace anything unless its broken lol."


Do accumulators actually go bad and how often do you need to replace?
Turns out the answer is not simple.

In

that surfaced recently a very clued-up person provided what he believes is a visual test of the accumulator.

Basically, a thin straw is inserted in the orifice and by the insertion depth, one can estimate the health of the existing accumulator sphere.

Well, I am not trying to bash anyone or to earn another star to my troll status, I just think that the above mentioned test is utterly useless. If the straw can be inserted deeper than 2.5-3 inches into the sphere, the latter is long gone. But the accumulator will not be performing its function even if the straw doesn't go deep. Why?

Simple -- the accumulators are metal spheres charged with nitrogen and a rubber diaphragm. Pressure is very high, well exceeding 1000 psig. v12uberalles has an article with the operation of the SLS system and what the accumulators look like when cut open:

http://v12uberalles.org/Replacing_Accumulators/Replacing_Accumulators.html

Wikipedia also has a nice write-up on hydropneumatic suspensions in general:

https://en.wikipedia.org/wiki/Hydropneumatic_suspension

For the sake of argument, let's say the existing accumulator sphere loses 50% of its charge, which initially was 1000 psig. The membrane inside, which one will be probing with the straw, is still "inflated" by the remaining gas (pressurized at 500 psig). It will feel to the tester as good as new. The same conclusion will be reached even if the sphere loses over 90% of the initial charge and is left with only 100 psig nitrogen. Only when the diaphragm is ruptured and the pressure is bled 100%, one will be able to insert the straw all the way in.

Damping properties of the suspension will be severely compromised when the ability of the accumulators to absorb energy is diminished. I do not think one should wait until all the nitrogen is lost to replace. Recommendation or not, I believe that the accumulators should be replaced at the recommended service interval (and probably even sooner if the vehicle is not driven regularly, as mine).

The attached pictures show how my spheres, which have seen only 52,000 miles and have been on the car for 25 year measure up. You be the judge.

I'd argue that a far more conclusive test for the health of the system is the appearance of the fluid. If the bleed screw at the leveling valve is carefully opened and some fluid is drained (extra care needed, please read the v12uberalles article), excessive amount of foam will be a good indicator that the accumulator spheres are shot.

Hope this long posts provides some clarity and will help many.

Best regards,
Steve