87 300TD self levelling suspension query - PeachParts Mercedes-Benz Forum

locry · #1 10-18-2006, 10:10 PM

i've done a lot of searching and have read a lot about the SLS, lots of helpful threads...

anyway,... this is what i gathered:

stiff ride at the rear MAY mean shot accumulators.

Shot accumulators eliminate the "damping" capability, thereby also eliminates normal suspension travel, effectively locking up the struts, this also eliminates spring action. Correct? so the bouncing is caused by the TIRES only.

I don't think i have shot accumulators because with the engine running i can push down on the car and it definitely still has suspension travel... so what can be the cause of my stiff rear ride?

Another thing, some people correct their ride height by adjusting the control rod at the controller, is this the right course of action? From what i understand, the SLS is supposed to compensate for added weight at the rear, so if there is no extra load, the car is supposed to be in equilibrium height-wise WITHOUT help from the SLS. IF the car is unladen and it still sits too low then adjusting the CONTROL ROD is just covering up for the sagging. This situation causes the SLS to activate ALL THE TIME just to maintain normal ride height... correct? I'm under the impression that the SLS is only supposed to kick in when there is EXTRA weight at the rear.

So... what should be done to properly correct ride height? or is this an acceptable way to do it?

Lastly, with the engine running, if i can bounce the rear of the car with the suspension system and not just the tires does this indicate my accumulators are still ok?

What exactly is the definition of normal ride height? when the car sits at the driveway with 2 passengers at the front and 2 at the rear?
How long does it usually take the car to rise to normal ride height?

Bio300TDTdriver · #2 10-19-2006, 12:49 AM

I would like to know too.

JimmyL · #3 10-19-2006, 01:01 AM

OK, my little bit of advice is based on the SLS of a W123 wagon. I think they are pretty much the same as the W124, but I don't know if any differences.
First, as I've said many times, a wise man once told me "Replace the accumulators, it's always the accumulators". Seems to be very sage advice so far, as I've had two wagons, and accumulators solved both of them. The 80's was very soft and sagging. Bounced softly. Wouldn't adjust height correctly. The '85 was bouncey, but it was a harsh bounce. Very tooth rattling......
You adjust the height via the linkage from the rear valve assy. Then, the SLS adjusts the height to compensate for weight added in the back. It raises quite slowly usually. Hard to see really.
Others will chime in I'm sure. The SLS is not difficult at all really.

Hit Man X · #4 10-19-2006, 01:06 AM

How did ya bleed it after ya installed the accumulators?

JimmyL · #5 10-19-2006, 01:19 AM

It is a self bleeding system. Having said that, there is a bleeding nipple on rear valve assy, just like a brake bleeder. For a faster bleed when changing fluid.......

Bio300TDTdriver · #6 12-21-2006, 04:36 PM

???

oniondip1 · #7 12-21-2006, 05:53 PM

I just finished installing both yesterday on my 1987 300TD. I had a horrible ride, any bump would send me bouncing into the headliner for quite some time. The new accumulators have cleared this problem up completely. It handles like a different automobile, smooth over even very rough roads.
From my research (I am definitely not an expert), it appears that adjusting ride hight with the control valve does nothing to "activate" the SLS. It is a system that is always working. There are no traditional shock absorbers or struts. There is always hydraulic fluid moving in and out of the strut, the control valve simply changes the amount locked in the system. This post made sense to me...not sure if it will to anyone else.

kerry · #8 12-21-2006, 06:16 PM

Quote:

Originally Posted by oniondip1

I just finished installing both yesterday on my 1987 300TD. I had a horrible ride, any bump would send me bouncing into the headliner for quite some time. The new accumulators have cleared this problem up completely. It handles like a different automobile, smooth over even very rough roads.
From my research (I am definitely not an expert), it appears that adjusting ride hight with the control valve does nothing to "activate" the SLS. It is a system that is always working. There are no traditional shock absorbers or struts. There is always hydraulic fluid moving in and out of the strut, the control valve simply changes the amount locked in the system. This post made sense to me...not sure if it will to anyone else.

That's my understanding also. The system is always operating since it provides the shock absorbing feature of the suspension.

jcyuhn · #9 12-24-2006, 05:24 PM

The SLS system always supports a portion of the weight at the rear of the car. So it is "active" even if the wagon is completely unloaded. If the SLS system fails, the rear of the car sags down. I occasionally see 123 wagons running around town dragging their tails. Haven't seen that on a 124 yet - but I'm sure it's only a matter of time.

Change the accumulators. There's nothing else that can wear out and cause a harsh ride.

- JimY

#10 12-24-2006, 06:26 PM

Yes, it's always lifting the body. My TD used to lift it's self about 4" every morning because the system would leak down overnight.

europower · #11 12-24-2006, 11:47 PM

I just replaced acumulators on my 87td,it solved the bounciness issue but i still have a loud clunk sound in the rear,especially if im driving really really slow,say im backing out of my driveway and the slightest change of terrain evenness will produce a loud clunk sound from the rear,i did not see that my rear shocks were leaking but they are old,could this be it??

Marie85 · #12 07-18-2007, 08:22 PM

I would like to change the accumulators in my 1987 300TD-T. Does anyone know where they are located?

Thank you

Biodiesel300TD · #13 07-18-2007, 08:41 PM

Bouncing is usually the accumulators. Just last week I change my accumulators on 123 wagon. And boy howdy!, what a different ride.

It was super bouncy before.

The accumulators are nearly round and are located just inside of the rear tires. You can't miss them.

tankdriver · #14 07-18-2007, 09:09 PM

Had mine changed when the back end felt like I was riding in choppy seas. The mechanic told me they were overworked due to sagging springs (haven't had a chance to change them yet).

Marie85 · #15 07-19-2007, 10:36 AM

I still can't find them. The prior owner must have removed them without replacing them. Can someone please post a photo of where they are located? I would really appreciate it. Thank you!