6.9 suspension repairs - progress on trusty rusty

[WGB]

Hi S Class,

Just for interest sake what was the colour of the oil on the hydraulic dipstick before you drained it. Styria says it can be quite clean on the stick and filthy below.

Bill

[s class]

Bill yes, on the dipstick it looked clear and new.  So I was completely taken by surprise when I drained the oil

[CraigS]

That's why it is extremely important that the filter is in place and changed periodically. Cheap insurance. As always, it is one of those overlooked parts - like not draining the oil cooler when changing the oil on a Euro. There is a further 2 lt in there.

[koan]

At the time I  changed my front struts I took out the "oil" tank to give it a coat of paint. The fluid in the bottom of the tank below the pick up was very slightly cloudy as if contaminated by moisture. As you are probably aware by now the pick up for the fluid is angled upwards inside the tank to avoid sucking up any sediment.

I attempted to flush out the system by removing the return line at the regulator and directing it into a bucket with a piece of plastic tube. With the mechanical link on both level controllers disconnected and the engine running I operated the levers on the controllers so the car went between fully up and fully down several times until I had about 2 liters of fluid in the bucket, or  actually on the garage floor as I knocked the hose out of the bucket at some stage..

I'd suggest something similar would work for you, with the addition of removing the struts and "pumping" the old fluid out - if you are not replacing them that is.

(BTW: the levers on the struts are not supposed to moved beyond +/- 45 degrees of center.)

koan

[WGB]

Hi S Class,

The "Mercedes-Benz Technical Companion" by Bentley Publishers has on Page 252 a 2 page article on a fluid flush for a 126 self levelling rear suspension by a method they call "Bleed and Feed".

I know you are going to rebuild the lot but it may be worth a look with some adaptation for the 116 hydraulic suspension.

It is too late tonight and I am busy tomorrow but will PDF the article and e-mail it to you Thursday or Friday.

Bill

[s class]

koan, Bill, thanks for the suggestions on flushing the system.  What I think I will do once I have that info Bill, is to flush the system and observe what comes out.  If the fluid/dirt looks really bad it may be the final convincing I need to replace the rear struts and valves. 

koan, you talk about moving the levers on the struts max 45 degrees either way - surely you mean the levers on the levelling valves?

[koan]

koan, you talk about moving the levers on the struts max 45 degrees either way - surely you mean the levers on the levelling valves?

Quite right, I do mean the levers on the leveling valves.

If you are watching Bill can I have a copy of "Bleed and Feed" please?

koan

[WGB]

koan, you talk about moving the levers on the struts max 45 degrees either way - surely you mean the levers on the levelling valves?

Quite right, I do mean the levers on the leveling valves.

If you are watching Bill can I have a copy of "Bleed and Feed" please?

koan

Ok Guys,

If I have time this afternoon I will PDF it and e-mail it to the pair of you - otherwise it will be in the next day or two.

Bill

[s class]

I have ordered new rear struts from the dealership.  I should have them late next week apparently. 

[s class]

Today I removed the two front struts, the 3 front spheres, both levelling valves and an assortment of crusty hydro tubing. 

A lot of the hydro tubing at the rear of the car is so badly corroded that I will be replacing it.  Most of the tubing and fittings up front it seems will be reusable.  Its all going off to be ultrasonically cleaned this week. 

For those not familiar with it, replacing the right front sphere under the battery is a bugger of a job.  The main inconvenience is the two forward most mounting bolts for the sphere which are neatly concealed under that cross member that supports the battery. 

The first pic shows what I found after removing the battery tray.  I quickly decided to remove the winscreen and headlight washer pumps and tubing to get better access as shown in the 2nd pic. 

the 3rd pic shows my two very sad looking levelling valves. 

[s class]

styria, I'm amused by your comment about removing the mounting bracket with the cell, because once I finally had it free, I looked at the bracket, thought 'hey' and looked under the fender to see two bolts.  Next time I know.......

As to cleaning the area, all that tubing in that area is coming out for ultasonic cleaning, and with the washer pumps out I think I stand a chance of getitng the area decently clean.  But as usual, I saw other stuff that should be done at the same time - like the 3 pipes for the engine oil tank - I realised that if they were out of the way I could reassemble much more easily with a much reduced chance of introducing dirt - and of course those hoses need doing anyway.....

[CraigS]

One thimg you MUST do is to clean up the wiring going into that mounting block below the battery tray. It can be a major source of problems, and because it is hidden, and exposed to battery acid and the like, gets extremely dirty - as you can see.

[CraigS]

This might also help those that have never seen what new levelling valves should look like.

[s class]

Craig, those valves look really nice.  I'm getting reconditioned units from styria. 

Thanks for the tip about cleaning the wiring block. What's its function?

On the positive note, despite all the grot and small creatures I found down there, there was no rust anywhere.  It could have been a lot worse. 

[CraigS]

I don't know what everything is in there. You would need to trace each wire in/out, but I do know that some of it relates to the ignition
circuit.

Just looking at these photos again, it would be very tempting to clean up all of the brake lines - have them cad plated etc. , replace hoses, clean paint work, renew/clean wiring, etc. but just in that one small corner, there would probably be a good 20 hours or more in cleaning it all up.