On this occasion, I didn’t bother getting the valve.  It looked like it had been leaking.  I’m not at the point of diminishing returns on this car.  It’s taking up space and I rarely get the time to work on it.  I prefer to spend my time on projects that will improve my actual cars.

Now I have access to the front of the car, I will remove the horns, and I want to try and remove the wheels again.  I tried before and even with a breaker bar I could not budge the lug bolts.   After that, I’ll sell the rest of the car.  there are some good rust free panels, but I don’t have anywhere to store them. Originally, I was going to take the front bumper, but it is not in great shape.

I spent some more time getting the car out from the corner where it has been for the last few years. I used my supercheap auto vehicle positioning jacks. The brakes are still locked on, even after cutting the hoses. These jacks are not easy to push a car like a 420SEL. I find I cannot push them forward or backwards on my own, only side to side. It was quite a time consuming process moving the car from side to side to get it into a more accessible position.

Now the SLS is removed, I’ll soon sell the car and free up some space.

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The fluid in the 560SEC looked fairly dark.  I last flushed it in 2019.   It seemed to take on this colour once the system was finally working properly.   In a previous article I outlined how a previous mechanic had the SLS lines reversed.   This resulted in low ride height.   I guess this was preventing flow, and therefore once things were flowing properly, any leftover debris in the system came through the fluid.   The picture above shows the old fluid.

I’ve covered the procedure for a W126 self-levelling rear suspension flush before, and it really is very simple.    The first step is to remove all the old fluid from the reservoir, and top up with clean fluid.

From there, I attached a clear hose from the return and put the end of that hose into a container.   In this case I used an old snow foam container.    Once this is ready I started the car and let the dirty fluid collect in the container.   The flow is low, so this job can easily be done with one person.

I also checked the filter.   It was a bit dirty so I changed it, and I’ll get a new filter for the 300TE.   Having a lot of debris in the system can mean a dead sphere.  I’ve driven a car with dead sphere and its really noticeable.    It doesn’t seem like one of my spheres is dead.

Once I saw clean fluid coming out as part of the flush, I turned off the car and then topped the reservoir up again.    Doing a w126 self-levelling rear suspension flush is a good simple job that is easy to do at home. The final photo shows the job complete and the reservoir topped up. ZH-M is clear, so the colour of the fluid should reflect that.

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The system ensures that even with a heavy load in the rear of the car, the suspension remains level.    Keeping the car level improves handling and safety.   It is actually quite a simple system, derived from the more complex system on the 6.9.   This system, in turn was based on the Citroen DS suspension.   At the rear of the car, there are struts for the self-leveling rear suspension.  These replace the shock absorbers.  The struts use hydraulic pressure, from a pump attached to the engine.  Unlike the 6.9 or the DS, there are springs, but they are quite soft as the strut does most of the work.

As these cars have aged, the self-leveling rear suspension rarely gets any maintenance.    The hydraulic fluid should be changed periodically and is a filter in the reservoir too.   This can be cleaned or replaced.

I was not sure when this was last done on my W126 cars.   I purchased a couple of filters and a few bottles of the correct hydraulic fluid.   The 300SE was first.   The filter is easily removed from the top of the reservoir.   This allows access to the fluid, which I removed with a turkey baster.   I then used a rag to clean out the inside of the reservoir, before topping it off with clean fluid.

To flush the system, an 8mm hose can be attached to the return line.   The engine is started and the fluid is gently pumped through.   Unlike the power steering system, the fluid volume at idle is quite slow and the job can be done with one person.   Once all the dirty fluid is pumped through the system, the engine is be stopped and the reservoir topped off to the correct level.

After the flush, the new filter is fitted and the return line re-connected.   The new fluid is almost clear, a big difference to the brown colour of the old fluid.   The old fluid seemed a bit thicker too.  The old fluid can be seen in the coke bottles in the photo below.

I probably could have gotten away with cleaning the existing filter, but I didn’t know how old it was, so I replaced it.

From there, I moved on to the 560SEC to repeat the procedure.   The fluid in the 560SEC was a bit cleaner, but it had a greenish hue.  Almost like there was a little LHM in there.

The same procedure worked well for both cars, and I used about four litres of the fluid overall.   I flushed the 560 for a bit longer as I was still getting the greenish colour through the system.

It is a bit hard to see, but the old fluid from the 300SE had more particles suspended in it – it is a bit browner.   It is the one in the coke bottle, the SEC fluid is the one in the water bottle.   Both were quite dirty and I am glad I have done this simple procedure.  I was able to do both cars in about 40 minutes.

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