I've read everything I can, and followed procedure, but still cant get suspension to rise. The entire system has been removed, refurbished and re-installed. Pump was bled into tank, good stream of fluid. The control disc is all the way CW to the stop, which is N position. I raised car and ran, the dash light was red and is now not on. If I pull the knob out to other positions the light turns on. Lowered the car, and have run at 2000 rpm for @10 minutes, still no rise anywhere. The level in the tank doesnt seem to be dropping at all.
From what I read in manual,the 5th cylinder needs to fill up to pressure, then it releases the valve to fill all the rest.
Any tricks out there that I could try?
Any particular spot I should crack a line to see if fluid is flowing? Control valve or at accumulators?
Hi Robert
If you have the bleeder valves at the accumulators (under battery tray you can access the front), then I would start there and bleed some fluid off. Be careful as I am sure you know there is extreme pressure present here!
If the system is "up" and running you will get return flow back into the reservoir, so look inside the tank with a flash light and see if you see return flow.
also check your leveling valve arms. when the suspension is down, the valve must be in the "filling" position, thus the arm must point towards the ground at roughly 45 degrees. This signals the valve to send fluid to the strut to "pump up". Once level the valve cuts out. I think your problem lies with the leveling valve, check the arms and connection to the sway bar first.
I have the earlier version without the bleed valve.
I think you have the leveler valve backwards, up is fill, down is lower. (at least for the front one)
When the car is down, the lever is up. If you jack the car up, so the wheel hang it is down.
How long should it take to fill an empty system?
Sorry yes you are correct I had the arm position backwards. So when the suspension is down, the arm will be 45 degrees towards the sky, not ground. This is the "signal to fill" to the valve.
On my 6.9 if it is completely down, then all that is required is start up and idle (no revving), then it takes about 30 seconds. Slow at first, then rapidly, so I would say from 30 sec to 45 sec, it does the rising part.
Once cut - out pressure is achieved (in the pressure regulator) then the flow from the pump is reversed back into the tank. have you checked the little gold filter inside the pressure regulator? Sometimes they can be clogged with crud.
where is the gold filter located?
Look at the pressure regulator. There is a 12mm hex bolt pointing towards the firewall. Remove this bolt and deep inside this channel sits the filter. You must remove the filter by a pick or suck it out with some hose and syringe. Careful as these are NLA. Give it a few blasts of air and carb cleaner. Also replace the o ring on the shaft before install.
Cleaned some gunk out of there, no immediate change, though I did not run engine very long.
After reading everything I could on M1oo site, I think I will take the control valve and pressure regulator off and take apart and clean everything.
Since I was able to fill the 5th cylinder and turn the light off, I suspect that there is something keeping the fluid from being directed to the leveling valves.
Poor car has sat for so many years, it's best not to trust anything. I can always swap from the parts car also.
Not a bad idea. Could be a tiny bit of crud causing one of the check ball valves not to seat properly. Make sure you keep track of the balls in the height control switch. The top ones are bigger than the bottom ones. There is also an o ring between the pressure regulator and the height control switch.
Today I took apart and cleaned the switch and the pressure regulator.
The big screw on the top of the switch was stuck and I managed to break it off. >:(
Got the other one off the parts car, it was easy to get that screw off, so I cleaned that one out.
Put everything back on the car and not much difference. After I shut the car off if I moved the switch I could hear clicks and fluid moving somewhere in the system.
Next step is to change pumps. I put the one from the parts car on originally. The original one I at least know it was working previously,so maybe the pump I used is not supplying enough pressure even thought there is a good flow of fluid from it?
Are you getting return flow back into the reservoir?
How would I tell? With the lid off I never noticed any disturbance in the fluid.
I found that strange, as you would think the fluid being pumped would at least be re-circulated somehow.
What line is the return line into to regulator?
Would no return flow be indicative of bad pump?
The return flow can be hard to see but if you shine a strong light into the fill hole and onto the bottom of the filter you should see a slow trickle.
If the warning light goes off you should have reached cut out pressure and then the reverse flow happens.
Usually the pump is the more robust part of the system.
Some guys rap the large bolt on the pressure regulator with a soft hit hammer to shock loosen potential dirt inside the regulator but I would be hesitant to try this.
Maybe strip out the top bolts on the pressure regulator and clean the check valve out. They can be super tight though and of course you need fresh sealing washers for assembly.
Edit
Success! My son came by so I showed him the car. I had noticed that the back was beginning to have some bounce in it if you bounced the rear fenders. Anyway, started the engine and bounced the 4 corners a bunch, and first the back rose, and then more bouncing got the front to come up. Perhaps moving the valve back and forth (loading and unloading the system) cleared thing out somewhere in the system.
Need to finish the brake job on my 300SE that is on jacks behind the 6.9 on Monday or Tuesday after parts arrive and then I can go on my maiden voayage.
:) :) :)
PS anyone have a spare screw that goes on the top of adjuster valve?
Nice! Might have been the switch cleaning that did the trick methinks.
Finally got to drive the car about 8 miles!
Engine runs smooth, though I have rebuilt the spare AAV and waiting on a gasket and hose to reinstall and then be able to adjust the idle down to where it should be.
The suspension is smooth and gets to the correct height, though driving below 1500 rpm the red light comes on, when I get to about 1800-2000 it goes out. I noticed that when I turn the car off I hear a hissing or fluid flowing noise from probably the rear height controller and the car will drop about an inch in the rear. I am guessing that means there is an internal leak in it that need to be looked after.
one of the rear hydro struck has a decent leak, so will need to swap in one of my spares and hope that one is better condition.
The main fuel line into the fuel distributor cracked right near the metal portion. I am trying to splice in a temporary patch line but still getting a drip, so I need to solve that before I can drive anymore. Those 2 fuel lines look like a pain to get out. I have found metric hose and the original hose collars. Has anyone ever used them to rebuild these lines? I dont want to buy their $1600 crimper, so I will have to figure something else out. https://www.belmetric.com/crimping-tool-cohline-c-14_1318/cohlcrimp-cohline-crimping-tool-p-7987.html?zenid=af5rgt5eoo0cf0t20rl2jqpjh6
https://www.belmetric.com/hose-collars-c-14_1319/?zenid=af5rgt5eoo0cf0t20rl2jqpjh6
Well, the rear hydraulic ram that is leaking is likely your problem as to why the light is coming on and why the car falls after you turn it off.
Regarding the fuel lines, if you're talking about the rubber ones they just buy new ones. They're still available. If you have access to underneath of the car, it's not a bad job......provided they're not rusty, of course.
feed line 116 470 57 75 is NLA
return 116 470 50 75 is still available
I found this:
http://www.m-100.cc/forum/topic.asp?TOPIC_ID=8220
My local NAPA can probably crimp new hoses on for me, but the end crimp part is different from stock, though if I put new sleeving on it, it will be covered up and no one will know for about 40 more years.
I just placed an order for both lines, we'll see what they have.
Quote from: rumb on 22 September 2016, 06:51 PM
Finally got to drive the car about 8 miles!
Engine runs smooth, though I have rebuilt the spare AAV and waiting on a gasket and hose to reinstall and then be able to adjust the idle down to where it should be.
The suspension is smooth and gets to the correct height, though driving below 1500 rpm the red light comes on, when I get to about 1800-2000 it goes out. I noticed that when I turn the car off I hear a hissing or fluid flowing noise from probably the rear height controller and the car will drop about an inch in the rear. I am guessing that means there is an internal leak in it that need to be looked after.
one of the rear hydro struck has a decent leak, so will need to swap in one of my spares and hope that one is better condition.
The main fuel line into the fuel distributor cracked right near the metal portion. I am trying to splice in a temporary patch line but still getting a drip, so I need to solve that before I can drive anymore. Those 2 fuel lines look like a pain to get out. I have found metric hose and the original hose collars. Has anyone ever used them to rebuild these lines? I dont want to buy their $1600 crimper, so I will have to figure something else out. https://www.belmetric.com/crimping-tool-cohline-c-14_1318/cohlcrimp-cohline-crimping-tool-p-7987.html?zenid=af5rgt5eoo0cf0t20rl2jqpjh6
https://www.belmetric.com/hose-collars-c-14_1319/?zenid=af5rgt5eoo0cf0t20rl2jqpjh6
The slight drop is normal when you get out of the car as the axle is being unloaded thus the leveling valve is readjusting itself. Red light coming on means pressure in the main accumulator is not being sustained. Points to weak pump or faulty pressure regulator or both. Or trouble with the height control switch.
It's a shame that something like a fuel hose is no longer available. I recently learned that Mercedes discontinued rear brake pads for W108/W109/R113. Things like that do't make mush sense.
Daantjie, he mentioned that one of the rear hydraulic rams was leaking. We can't yet rule that the pump or pressure regulator are problematic until the system holds fluid in under pressure.
I've read about the process and difficulty find parts to rebuild from rams, but has anyone rebuilt a rear? I know there are probably orings and teflon rings. Would just replacing the orings be sufficient to get a ram in working / nonleaking condition? Since I have spares and one known leaker, I think I will see what I can do with the bad one. I would think the orings do more to control leakage than the teflon rings.
The dealer replied to me that both fuel lines were NLA despite MB saying the return was still available. I asked them to check again, and I will also ask the classic center as they are better at getting parts from germany.
.............
The feed line is NLA for sure. You can get the proper Cohline polyamide lined hose from www.belmetric.com.
Some leakage at the strut is normal. Have you done a 12 hour leak down test as per the manual?