560 sec leveling valve

[GILBY]

Just changed the valve due to the arm on it breaking. The car now seems to sit normal at the rear when stationary but the front sits high.

when the car gets up to 40/50 mph the front seems to go lower making the rear seem higher. Is the valve the only thing that maintains pressure to the system or could there be a pressure leak or blockage somewhere? There's no fluid leaking from anywhere

 

[Dieselman]

The valve is the only height control.

 

[Sp!ke]

I dont know the sls arrangement on an SEC. I assume it is only self leveling on the rear?

If when you drive the rear raises then the SLS is doing its thing and raising the rear to the height it believes to be correct according the the adjustment of the lever on the sls valve. You can adjust the positioning of this lever to alter the ride height.

If the front sits too high (and assuming this isnt controlled by sls) then you'd be looking at making adjustments with different springs or spring pads.

 

[GILBY]

So if the rear is staying the same height and the front is changing height when at speed then it must be the valve?

I've also noticed if I park on slope facing down turn the engine off the front sits lower to where it should be.

Internal leak in the shocks maybe?

 

[Sp!ke]

I might be wrong but I didnt think the front of your car has SLS at all so your front wont change height.

Perhaps someone else can confirm.

 

[Dieselman]

My understanding is the SLS is rear only. That car rides too high at the front, probably due to the wrong springs being fitted.

 

[GILBY]

Original springs still fitted to car

 

[GILBY]

the piece which connects to the swaybar and other end of rod from valve, is this supposed to have any movement whatsoever?

 

[Sp!ke]

A picture perhaps would help understand what you mean but there should be an arm on a fixed point that moves up and down with the movement of the torsion bar ride height. This controls the sls system which has three positions. Up, down and neutral.

Tricky to describe without pictures really

 

[GILBY]

I was talking bout the arm that's fixed and sits parallel above the valve on the sway bar

is it supposed to not move at all.

I've noticed there's a bit of play when lying underneath and grabbing the rear end and rocking it up and down

I don't remember that part moving a while back when I replaced the connecting rod

 

[Sp!ke]

No it is supposed to be fixed. Only the arm should move.

 

[grober]

There is a bracket that should be " CLAMPED" to the anti-roll bar as Spike has already said . It's function is translate the rotational movement of the bar into backwards and forwards movement of the connecting rod which in turn operates the lever on the level valve. It should not rotate on the antiroll bar. Ride height adjustment front to back should be adjusted to be level by shortening or lengthening the threaded connecting rod with the engine running to power the self levelling pump. This assumes of course that the system components hydraulic struts and gas filled spheres [ the suspension medium] along with the assisting springs are all working correctly.

Ps if the level setting changes with increased engine revs it implies that the pump is then able to work harder to maintain the set level thus changing it from idle / rest where it has sagged. This might imply there's something else up with the system?

 

[GILBY]

Thanks for the detailed analysis.


If the valve is the only component that regulates ride height and pressure to the hydraulic rams where is that escaping to when revs are reduced could the rams be bad or springs be weak?

 

[grober]

Thanks for the detailed analysis.


If the valve is the only component that regulates ride height and pressure to the hydraulic rams where is that escaping to when revs are reduced could the rams be bad or springs be weak?

The most common fault with these systems is either rupture of the diaphragm inside the spheres or loss of gas pressure. Unless there is visible evidence of fluid loss its unlikely the hydraulic struts would be leaking. Loss or lack of fluid would be evident from examining the level in the engine compartment reservoir- if there are airleaks then the system may require bleeding

 

[GILBY]

Would air in the system cause the rear end not to rise when weight was added to the boot or is that something wrong with the valve?

 

[Sp!ke]

My experience of SLS on MB cars of this vintage is that it tends to be sluggish and need a bit of revs to get it to start leveling.

I would suggest moving the sls arm to test rather than play with weight in the boot.

 

[jaymanek]

These systems dont respond quickly, they level out after some driving...