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  #1  
Old 04-25-2009, 04:24 PM
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SLS suspension- valve rebuild weirdness

I've had some trouble with the self leveling suspension on my '85 wagon...
firstly, it rides really rough...makes a big "BAM" every time i go over a bump...a thread about it HERE from years ago...still unresolved after replacing the accumulators.

Another current problem is that i am unable to get the rear lever to effect a change in ride height. I rebuilt the valve yesterday. Put it back in today and still can't get moving the lever to do anything.

Question: When I reassembled the valve, I had to REALLY force/push in the PISTON to get the CAM into the position shown in the attached photo...(which was in the instruction guide that came w/ my O-ring replacement kit)...such that the CAM is partially COVERING the piston. I force the piston in, and put my cam in the postion shown in the photo. Reassembled the valve, and it seems that tightening the "valve halves" together with the bolts would've forced the pison in even further. Anybody know if this is the correct position to reassemble?

Question:
Would you guess that the SLS MOTOR might be at fault? Is there a (relatively) simple way to test?
Attached Thumbnails
SLS suspension- valve rebuild weirdness-valve-cam.jpg  
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'85 mercedes euro 300TD

proud owner (in days gone by) of:
'77 mercedes 280e
'80 mercedes euro 250
'80 mercedes 300TD
'82 mercedes euro 250
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  #2  
Old 04-25-2009, 09:02 PM
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SLS test

well, i believe i at least have a good SLS pump. I disconnected the lower (supply) line at the SLS valve, and started the engine...and got a good stream of fluid coming out of the line. I'd imagine that means the pump's working.

now i just need to figure out why my ride height's not changing!
anybody got any ideas or experienced a similar problem?

also, could it be that the harsh ride in the rear is attributable to the SLS not functioning? (i.e. if i'm riding on springs...the ride would be harsh?)
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'85 mercedes euro 300TD

proud owner (in days gone by) of:
'77 mercedes 280e
'80 mercedes euro 250
'80 mercedes 300TD
'82 mercedes euro 250
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  #3  
Old 04-25-2009, 11:09 PM
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Sorry, can't help on the valve question but in my opinion, your ride would not be harsh if you are riding on the springs. It would be bouncy but not harsh. I suspect your valve is not working correctly and maximizing our height making the system think you have a heavy load and harshening the ride. This is speculation on my part because my bad ride was caused by worn accumulators.
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  #4  
Old 04-26-2009, 12:55 AM
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lee,

Don't forget that moving the adjusting arm on the valve does not provide an immediate response. Apply some throttle to raise the rear after moving the arm.
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  #5  
Old 04-26-2009, 09:21 AM
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Quote:
Originally Posted by jt20 View Post
lee,

Don't forget that moving the adjusting arm on the valve does not provide an immediate response. Apply some throttle to raise the rear after moving the arm.
Yep, it will drop like a rock when moving the valve, but the rise is very slow and you have to give it several seconds to "get going". Level increases faster with a higher idle.
I would look for thread about the valve rebuild procedure and pics. You can at least see if your pump/cam is assembled correctly.
If it isn't then the rear won't lift, and I, uh, know this by experience.....
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  #6  
Old 04-26-2009, 10:26 AM
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If the cam was put in backwards, you should be able to spin the valve lever toward the differential and get it to respond.
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  #7  
Old 04-26-2009, 01:06 PM
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Quote:
Originally Posted by blankenship View Post
I've had some trouble with the self leveling suspension on my '85 wagon...
firstly, it rides really rough...makes a big "BAM" every time i go over a bump...a thread about it HERE from years ago...still unresolved after replacing the accumulators.

Another current problem is that i am unable to get the rear lever to effect a change in ride height. I rebuilt the valve yesterday. Put it back in today and still can't get moving the lever to do anything.

Question: When I reassembled the valve, I had to REALLY force/push in the PISTON to get the CAM into the position shown in the attached photo...(which was in the instruction guide that came w/ my O-ring replacement kit)...such that the CAM is partially COVERING the piston. I force the piston in, and put my cam in the postion shown in the photo. Reassembled the valve, and it seems that tightening the "valve halves" together with the bolts would've forced the pison in even further. Anybody know if this is the correct position to reassemble?

Question: Would you guess that the SLS MOTOR might be at fault? Is there a (relatively) simple way to test?
Hi

Your picture looks like everything in place.

You don't show your lever in the pic - its pointed down between the "F" & "L" marks right?

Where did you put the big bearing?

Good Luck,

Joseph
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  #8  
Old 04-26-2009, 01:22 PM
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aaaaaah

yeah, i gave it plenty of throttle and waited for response, but didn't get any, either way, w/ any amount of throttle.

definitely didn't flip the cam...made a note of which side was which...and confirmed that it looked exactly like the photo in my first post (which photo came straight from the "instruction manual."

dunno, man. crud...guess that valve's comin' back off?
with these instructions this time.
unless anybody's got any other possible explanations that don't involve the valve?
actually, before i go through the pains of removing the valve again, can i just disconnect the lever arm from the knurled shaft that comes out of the valve...and just start spinning the shaft until i see response?
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'85 mercedes euro 300TD

proud owner (in days gone by) of:
'77 mercedes 280e
'80 mercedes euro 250
'80 mercedes 300TD
'82 mercedes euro 250
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  #9  
Old 04-26-2009, 03:36 PM
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Quote:
Originally Posted by blankenship View Post
yeah, i gave it plenty of throttle and waited for response, but didn't get any, either way, w/ any amount of throttle.

definitely didn't flip the cam...made a note of which side was which...and confirmed that it looked exactly like the photo in my first post (which photo came straight from the "instruction manual."

dunno, man. crud...guess that valve's comin' back off?
with these instructions this time.
unless anybody's got any other possible explanations that don't involve the valve?
actually, before i go through the pains of removing the valve again, can i just disconnect the lever arm from the knurled shaft that comes out of the valve...and just start spinning the shaft until i see response?

Hi

I'm rebuilding my valve today also. Also confused!

I notice that when my cam is in the position shown in the picture - my lever is in the extreem fill position rather than half way between the L & F marks as shown in your 2nd set of instructions. I also have a '85 300tdt. Do you find the same thing with your lever? I first thought that someone had put the lever on in the wrong position but then it can only go in the position that will allow the bolt to pass through the slot in the shaft.

I also don't understand what the various parts of the cam are intended to do. Any ideas - anyone? Is there a description of how these valves work anywhere?

Joseph

It seems to me that if you rotate the shaft all the way around - that you will uncover the piston and it will pop up and then get in the way of the cam.
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  #10  
Old 04-26-2009, 05:56 PM
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good resource

THIS is a good resource.

i'm not sure how to make positive ID of the correct positioning, though.
if anybody out there can clarify situations that could cause this "no change in ride height" situation i'm going through...please don't hold back!
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~lee
'85 mercedes euro 300TD

proud owner (in days gone by) of:
'77 mercedes 280e
'80 mercedes euro 250
'80 mercedes 300TD
'82 mercedes euro 250
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  #11  
Old 04-26-2009, 05:59 PM
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When I overhauled my SLS, I had to splice in new hard lines near the subframe. Even though I thought I was being very careful, I ended up swapping the fill and return lines. The SLS didn't work at all other than maintaining base pressure. Once I put them on properly, the SLS worked fine.

Make sure you didn't swap the lines.
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1986 300SDL - Coda
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  #12  
Old 04-26-2009, 07:15 PM
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why did you rebuild the valve ?
is the ride worse/different now than it was before the rebuild ?
did the rear raise/lower with the control arm before the rebuild ?
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  #13  
Old 04-26-2009, 11:41 PM
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Quote:
Originally Posted by blankenship View Post
THIS is a good resource.

i'm not sure how to make positive ID of the correct positioning, though.
if anybody out there can clarify situations that could cause this "no change in ride height" situation i'm going through...please don't hold back!
Hi

Great info - pages 15 & 16 contained exactly what I was looking for.

Thanks,

Joseph
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  #14  
Old 04-28-2009, 08:29 PM
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glad

glad it could help.
it inspired me, too...i took the valve back apart and reassembled everything using that new post i mentioned..the control shaft-to-lever relationship was way off.
i'm back in action...raising + lowering!

question now still is: why in the heck am i getting this big clunky kaboom in my rear suspension every time i hit a pothole or go over a speedbump? the road noise and vibration back there actually seems significantly increased from other wagons i've ridden in. mostly, though, it'd the THUD!

so far, i've:
  • -replaced accumulators.
  • -rebuilt sls valve.
  • -replaced z links.


advice i've received is:
  • -rear subframe bushings (they look okay from the side...anybody know if there's a "how to" i've missed on how to inspect/replace them on a wagon?
  • -blocked hose(s) between actuator and accumulator.
  • -missing or deteriorated bushings on the top and/or bottom of the actuators?
  • -bad axle shaft(s)...how do you test?

thoughts on whether any of that's a likely culprit?
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'85 mercedes euro 300TD

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'77 mercedes 280e
'80 mercedes euro 250
'80 mercedes 300TD
'82 mercedes euro 250
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