Level Load? (PICT)
 

here is my 95 E320 wagon. 115k odo.

There is 400lbs in the bed. To me, the car looks like its sagging. I was under the impression the load leveling suspension was to prevent this sagging.

the accumulators were recently changed, new oil in the system and a valve put in (not a "new" one) . System was bled of course.

so is what you see normal behavior?


PICT (kinda big)

Needs a password
 

The linked picture will not open without a passcode. I received a message stating, "You need a username and password to log on to this FTP server." If you PM me, I might be able to help (owner of '94 and '99 E320 wagons).

On my 92 TE there’s a linkage that goes from the level control unit to I think the torsion bar lever that can be adjusted..

When I put one of those cargo baskets in the receiver for the trailer hitch and loaded it with an empty tool chest I was bring to my father in law the rear of the vehicle sat to low. I adjusted the linkage, made it shorter, to raise the rear end so vehicle would be level. When I came back from bringing him chest I set linkage length back to where it was.

oops sorry. i fixed the link. you should be able to see it now.

bump :D

the linkage for the leveling of the rear end is clamped to the rear sway bar and has been known to move.it's mainly designed to be the upper limit by pushing down on the lever arm on the valve.loosen clamp bolts first then with car on ground crawl under and slowly move clamp so as to move arm on valve upwards.caution------if you move it too far you will pump susp so far that it will act as though the rear accumulators are gone.

ok so, when I get under the car, I see the little link or whatever that connects between the valve and the sway bar. Is it totally okay to undo that link and actuate the valve manually so long as I dont over do it correct? I assume the car has to be running.

But all in all it does seem like come correction is needed right? the suspension should be holding those 400lbs level.

Obviously motor has to be running to maintain ride height.

Otherwise, rest of advice is right on.

yes you can get it to the correct height doing that but when you achieve correct level move lever on valve back to middle position[to stop going up] and then see what corrections you have to make to hold lever in centre position[when at right level].

nice looking wagon.mine has the same issue so im interested in your resolution:)

I assume I have to have the vehicle loaded eh? prolly pointless to try to adjust that little linkage with the bed empty.

New Findings!
 

okay dokay, I'm gonna keep posting in this thread so as to not clutter up the forum with redundant threads.

so, while the wagon is off, has no load in the bed theres an approx 2" gap between the top of the tire and the wheel arch. its very approximate but its gonna be my control.

I load up the bed with 300-400 lbs. the gap diminishes to like 0. the top of the tire is at or beyond the level of the wheel arch.

so I turn the car on. I am ASSUMING the bed should raise up to somewhere close to the non-load, engine-off height. It doesnt.

I unload the bed and put the rear wheels on ramps. measure again and my approx control height of 2" is still there. I load it up and the bed lowers as expected. I start the engine and as before expect it to rise. it doesn't. Now i creep under the car and detach the link between the control arm and valve. I rotate the lever-arm on the valve expecting the car to rise and lower. From what I can see, there doesnt appear to be any movement of the hydraulic shocks.

questions:

first off, am I correct to assume that the vehicle should obviously raise and lower in a fairly immediate fashion? with both weight and manual operation of the valve lever-arm?

secondly, whats next? new valve body?

Lastly where is the pump that drives these hydraulics? should I be able to hear or see it working? The valve body used to work and I find it hard to believe that such a simple valve would suddenly fail. BTW there are no oil leaks and theres plenty of oil.

I am not so sure it is an immediate thing. I have a 16v with a hydro rear end. I also have the little link on the sway bar and the whole shabang. Any way, when I was bringing home about 400 lbs of tile home it took a bit of drving (maybe a mile or 2) for the rear end to come up. I seemed to think I could feel/see it comming up when I was driving home.

Have you checked to make sure you have presure at both shocks? If it does not raise up after you are drving, that would be my first suspicion.

As for the pump location, mine is powered off the front of the engin off the exhaust cam. Your might be different but you should be able to trace a line off the hydro tank under the hood to the pump.

I tried this on my E320 wagon. Even with defective accumulators the back end rose and fell when the level valve arm was operated. It also made noise and bogged the engine slightly at full lift. The FSM suggests not holding this for long.
The pump is in the power steering pump housing.

Someone will hopefully correct me if I'm wrong, but I think the correct measure at rear is 12.75" from Star center (wheel axel) to fender lip. And should be .5" lower than measure a front wheel.

Bob

thats an awesome number. I totally didn't think to measure from there.




I don't suppose there are any electronics involved with this system eh? no switches, relays, fuses? I'm not really sure how to test to see if the pump is actually running. I don't know if the valve body is good or not ( are they really prone to failure? any other way to test?) but even so I'd still expect to hear the pump go under load. any other ideas on where to go next?

Hold on. I just measured. I'm at 14" 5/8 in the rear and about 15" 3/8 up front from wheel cap center to bottom edge of fender??

I found the "12.75" and ".5 f/r diff on another Benz site. Manual only appears to have data for using alignment tools. (As if DIYers have them). I don't know if the number is accurate. I was hoping a pro would confirm or correct me.

I don't suppose there are any electronics involved with this system eh? no switches, relays, fuses?
___None of the above. Only hydraulic pressure (with nitrogen gas in accumulators).

I'm not really sure how to test to see if the pump is actually running.
___Fluid will flow through resevour. Disconnect return hose from resevour, and continually add new fluid to flush system. It self purges any air in lines.

I don't know if the valve body is good or not ( are they really prone to failure? any other way to test?)
___Manual has procedures for presssure testing and as overnight procedure to ensure it's holding pressure. "Level controller" has very good rep for longevity.

but even so I'd still expect to hear the pump go under load.
___It uses the Power Steering pump _ but two different fluids are used!!! Because Power Steering pump is runnig constantly, I doubt you'd hear any different sound under load. Rear height should change within moments of turning on motor.

any other ideas on where to go next?
___We're both in the same wagon. Ride height of mine is similar to yours with little change loaded. I felt the handling was better when my accumulators weren't working properly. The handling of mine feels worse with the rear so high.

Do you mean the owners manual? I'm gonna go look right now. I've just gotta get this thing to level itself.:(

Not in Owners Manual. I' referring to the Model 124 Maintenance Manual (a 2CD Set)

1988 300 TE 280K miles. I'm dealing with the same problem. Replaced rear shocks and accumulators but getting no pressure from pump. Does pump then need replacement or is it fixable? I see that this part is not available through this shop. Any comments appreciated.

i have found that sometimes the feed line to the pump gets blocked.take out the level dipstick and using a rag see if you can pressurize the tank with compressed air.this should start the pump running again.

Thanks for the info but tried that and to no avail. New pump coming I guess.

so get this. I went to the level-oil reservoir and opened the lid while the car was running. You have to be careful not to get oil everywhere as the return line is in the lid. Anywho it very obvious that there is movement of oil. you can clearly see the oil coming into the the tank. So I suppose that means that my pump is working. Which I suppose leaves no other component except the valve body. I don't have the CD manuals, is the procedure for pressure testing the valve body on the forum anywhere?

kirke333
AutoPartsGuru shows rebuilt PS pump w self-leveling @ $446 OUCH. I'd try used through car-part.com

AtlBenz
I don't know if the test procedure is on the forum. I can email you "32-0530.pdf" (324k) "Testing pressure oil pump and level controller..." It notes nominal pressure at level controller of 133 bar. There are 2 other pdf specific files and many more relative ones. Unfortunately, there's a lot of redundancy and the info has specs using MB alignment tools. Ironically, in one sentence it mentions the fender lip to center of axel measure. But I've never found actual numbers.

My inde's alighment rack is not avail, so I'm gonna take mine to a speciality alignment shop and have tehem check mine.

ok.ive been wondering for quite some time what the star to fender lip dimension should be.mine runs around 15" both rear wheels.does this means my rear springs have sagged?:confused:

hey mike, if you saw a post of mine, you'll see that mine are around 14.5-15" unloaded. I'm beginning to think thats kinda where these wagons are supposed to sit unloaded. my problem is that it wont STAY there like its supposed to once I load it up.

:confused: my wagon seems to ride right without a load but i recently picked up a pile of laminate flooring at the good ole homedepot and noticed the rear did not self level.the car will go up and down however if i manually operate the valve lever.perhaps the valve internals are shot

My understanding from comments on this and other MB lists is...

With engine off, load cargo, rear end drops due to heavy load. Turn engine on, pump activates self leveling and rear end rises to unloaded height. You can manually operate system with controller with engine on and rear will go up & down. However, if there is a problem in the system, it will not rise with cargo loaded. I think the test (cargo) weight is 300 lb.

If rear doesn't rise with loaded cargo, then one or combination of: [1] Leaking "fill" hose located under the resevour (most likely & cheepest thing to fix), [2] Leak in any of the lines or fittings, [3] Leaking accumulator(s) (very likely $200 for 2), [4] Bad pump (PS & Self leveling in one), [5] Bad controller.

If fluid is low, there's a leak in the system. Simple test of accumulators is ... turn on engine, partially remove fill cap containing fluid return hose - if fluid is foamy, nitrogen is coming from bad accumulator(s). This cap contains a thin mesh cylindrical filter about 4" long. You must use Febi #2615 Hydraulic Fluid, and put it into the resevour. Only Power Steering fluid goes into the PS pump.

Bob

Bob: thanks for the email. I'm gonna see what I can do. See below.


Chas: I just got home, had 377lbs in the bed. ride height went from 14.5 to 12.5 with car running. when I turned off the car, ride height stayed at 12.5 loaded. which implies to me that the LL wasn't doing it job.


A couple tool questions:

the fittings that hold the oil line on the valve body. what side are they? I remember being told there were "oil fittings" which apparently means that its some crazy non-metric size.

obviously i need a pressure gauge - holy smokes, I just did the conversion. I need a gauge that reads 133bar....um...that equals 1929psi......yikes. I hope I can find a gauge that reads that.

I'm not sure where to get the specific parts. It says I need the connector, union and test hose. it gives me numbers like (038) and (038g). I'm assuming those are some kind of internal tool numbers or something. how do I convert that to autozone/pepboys numbers?

thats a great list.

lets see. I have brand new accumulators, and the pump seems to be working (but I wanna pressure test for sure). so that knocks off [3] and [4]. [5] is a "new" used part so thats and unknown for me but as I understand it thats the last thing to fail. Which pretty much leaves me with "leaks" in the system. I suppose I ought to verify that there are no leaks before I pressure test because if there are then that'll be skewed. everything seems really dry around the valve body. so all thats left is the connections at the accumulators and then up front at the tank and I guess the PS pump.

To best of my knowledge the only non steel line is the hi pressure hose under the resevour.

I've read that some people unbolt the controller to allow a little extra wiggle room when changing the accumulators. I had my inde maniac do mine because I didn't have the strength to loosen the banjo bolt feed to accumulator.

Also be very careful with reattaching lines into controller. I read that they are very easy to strip. :eek:

Once the weather warms up we should do a measure survey. "What's the distance from Star [axel] center to fender lip, left & right, front and back."

Bob

Once the weather warms up we should do a measure survey. "What's the distance from Star [axel] center to fender lip, left & right, front and back."
yeh i second that motion:scholar:

well if you noticed, my valve body is a "new used part"...guess why.....I friggin stripped the original when reassembling after changing my accumulators. those oil fittings are a pain in the butt. and like I said I think they are some crazy size that regular metric sizes dont fit which didnt help.

I was just messing with the car now. Looked at the line coming out of the reservoir. you're right that its the only non-steel line. its all dry. I took out the filter and noticed it had a lot of sludge. So I cleaned it...hoping something that simple was to blame. 300 lbs later no luck.

sign.

If the fluid is old or very dark, try replacing it. Flush with the Mercedes fluid.

Did this with the '95 wagon and the rear seemed better afterwards.

Haasman