The nitrogen spheres provide part of the spring, allowing the fluid in the struts to be displaced somewhere. When they die, the suspension is the correct height, but will not move since the struts and spheres are full of hydraulic oil.

The struts are intoconnected through the height control valve, so they are always the same. One bad strut will cause the entire rear to squat, I think. I've never seen one list, either.

The rear suspension gets soggy when the struts go, as they are also the shock absorbers.

Since the spheres provide a considerable portion of the spring (all of it in the hydropneumaic cars!), simply putting shocks in place of the struts will probably simply cause a really low suspension. You would have to replace the springs, too, and I am sure they are not the same as the sedan springs, this being MB! You might be able to get the regualar suspension in Europe, so if you could get the part numbers maybe replace it. Lots of work and more expense, probably, than simply fixing what you have.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Good afternoon everyone. Question on the tach sender, the white goo behind it, can I just carefully scrape it out so I can solder the connections in there again? If so, can I use silicon to cover it back up or do I need to use something else. How about the tach itself, is it susceptible to the same soldering problems?
On the central locking, do I leave it unlocked then after 10 minutes try to lock it? I lock it and come back after work and it works except for the rear hatch.
Thanks again for all the replys.

__________________
96 Legacy LSi wagon
92 Mitsu Expo
95 525iT
1983 300TD clackclackclack sold
1972 Toyota Corolla wagon TE28 sold
1991 Galant VR4 pshhhhh non-op
1989 Montero RS pop's ride

Erik:

A buddy of mine tried to fix his tach sensor by re-soldering, but could get it to work any better than before. I think the cigarette butt fix works or it doesn't. Others may know more.

As for you tailgate lock, either it has a busted diaphram, a plugged or missing hose (meaning someone "fixed " it) or the linkage is off the lock and the vacuum motor is working but doing nothing. You are going to have to get the door lining off to find out -- get the instructions so you don't rip it up! Usually, when a hose is broken or a diaphram is torn, none of the locks work.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I'll tackle the accumulator question.

The car has two accumulators - one each for the right and left suspension. Each accumulator is about the size of a coffee can. They are sealed, but for one threaded opening where a hydraulic line attaches. This line runs to strut on the respective side of the car.

Internally the accumulator is divided in half by a thick rubber diaphram. One side is open via the aforementioned threaded fitting, the other side is sealed to the outside world. The sealed half of the accumulator is filled with nitrogen at a high pressure - about 20 atmospheres, as I recall.

As mentioned, the accumulator is connected to the strut. The struts are filled with hydraulic oil, supplied by the control valve. The volume of oil held by the struts varies with how far they are extended. Longer = more oil, shorter = less oil. When the rear of the car is lower, the strut is compressed more, and that oil has to go somewhere. It is pumped out of the strut and into the accumulator.

When the rear of the car is riding low, the control valve admits oil into the struts. Some of this oil moves into the side of the accumulator connected to the strut. Of course, adding incompressable oil causes the diaphram inside the accumulator to move, reducing the volume of the nitrogen side, and raising the pressure of the nitrogen. Because the pressure inside the system has increased, not all the oil admitted by the control valve goes into the accumulator, some of it remains in the struts. As a result, the struts must extend to contain the greater oil volume, and the rear of the car is raised.

As the car is driven the struts extend and shorten as the rear suspension moves up and down. In doing so, they pump fluid in and out of the accumulators. Each time the suspension compresses, fluid is pumped into the accumulator, pressurizing the nitrogen, and effectively increasing the spring rate of the strut/accumulator assembly, slowing and eventually stopping the downward movement of the cars body. So the accumulator is basically and adjustable spring for the suspension.

The reason old accumulators ride hard is because over time the nitrogen diffuses out through the rubber diaphram. As the quantity of nitrogen decreases, the diaphram is compressed more and more to reach the necessary pressure. The smaller the volume of nitrogen, the sharper the pressure rise associated with introducing a given volume of oil from the struts. The spring rates becomes very stiff very quickly, making the ride seem hard.

How's that for a Monday morning?

- Jim

You do know that there is a lever on the seat to adjust the hight.

No I do not. Please do tell kind sir. I don't have the stiff rear suspension and I do not have any leaks. I am beginning to have hope that this is just an adjustment, or the nitrogen needs recharging. Again thanks to everyone on this great board.

__________________
96 Legacy LSi wagon
92 Mitsu Expo
95 525iT
1983 300TD clackclackclack sold
1972 Toyota Corolla wagon TE28 sold
1991 Galant VR4 pshhhhh non-op
1989 Montero RS pop's ride

you have a knob to adjust the recline.You have a lever to make the seat go forward and backward.The third lever you find makes the seat go up and down.

Ok, I thought that lever was for adjusting the rear suspension.
I have another question. I wanted to mount a sub in the rear and I wanted some ideas on how to cover the rear cargo of a 300TD. Did they come with covers from the factory? Anyone used a different make for the cargo cover. Thanks again.

__________________
96 Legacy LSi wagon
92 Mitsu Expo
95 525iT
1983 300TD clackclackclack sold
1972 Toyota Corolla wagon TE28 sold
1991 Galant VR4 pshhhhh non-op
1989 Montero RS pop's ride

Jim:

When the accumulators go bad, they don't just make the suspension stiff -- they make in completely immobile. The struts cannot change length because the hydraulic oil won't compress and there is no longer any gas space in the accumulator to compress. The only spring left in the suspension is the bending the various parts and the tires.

You won't mistake dead accumulators for a stiff suspension, believe me -- the ones on my 300TE were shot when I bought it (one of the reasons I got such a good deal on it) -- these cars are not safe to drive if the accumulators are gone. If you want to try it, replace the shock absorber with a solid link and try driving the car. Won't take long to convince you something is seriously wrong!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Peter -

There are two failure modes for the accumulators. There's "most of the nitrogen is gone, the suspension still works a little, but the ride is really hard and bouncy." And then there's "the rubber diaphram broke and the suspension is now locked." Let's call the former tired acculators, and the later dead accumulators. I've experienced the first, guess you've seen the later. Just a matter of how long you wait to replace the accumulators.

Most people don't notice because it's such a gradual degredation in ride quality. But replacing a set of tired - but not dead - accumulators makes a huge difference in ride quality. My 124 wagon was 12 years old when purchased and still had the original accumulators. A new set did wonders for the backend - both the cars' and mine!

- Jim

Jim:

Ah, yes. As I stated, no mistaking this failure for anything else! Once fixed, they ride much better than the sedans (I have both).

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I picked up my Hynes manual for $9.00 at the local Pep-Boys. I do not own a 123, but they are so cool I had to get anything and everything on them to read.

Thanks. I got my HAynes manual from Pepboys too but at $13.00.

__________________
96 Legacy LSi wagon
92 Mitsu Expo
95 525iT
1983 300TD clackclackclack sold
1972 Toyota Corolla wagon TE28 sold
1991 Galant VR4 pshhhhh non-op
1989 Montero RS pop's ride

Erick,
Sorry for the delay, I am having PC problems and can not email. I could also not find you original thread. Here is their link which should give you everything you need.

http://www.********losgatos.com/

Thanks a lot Wade. I'll check them out. Do you have a contact person there?

__________________
96 Legacy LSi wagon
92 Mitsu Expo
95 525iT
1983 300TD clackclackclack sold
1972 Toyota Corolla wagon TE28 sold
1991 Galant VR4 pshhhhh non-op
1989 Montero RS pop's ride