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2001 CLK430 with the roll bars in the full up position

9K views 5 replies 2 participants last post by  serndipity 
#1 ·
2001 CLK430
New to forums so if I do this wrong please bear with me.
I have a 2001 CLK430 with the roll bars in the full up position.
Holding down the button for 10 seconds does not help.
I have read about holding the safety latches open and pressing down on the headrests (roll bar). I removed everything required to gain access to the latches and propped them open; I then loosened the screw on the hydraulic pump three turns and tried to push down the roll bar. Nothing. I then backed the car in the garage and had someone push the headrest down button while I stood on the headrests pushed off the ceiling. It worked! They went down and stayed down. I then removed the wedges holding open the latches then pressed the headrest up button. The headrest started going up, safety latches clicking and would not stop until fully up. Stuck up again!
I have no hydraulic leaks that I can see.
Is it possible the hydraulic block for the headrest is leaking internally?
Has anyone tried to rebuild one? (Have looked for drawings of it but no luck)
Purchased a PDF version of the car service manual but it has nothing on the Cabriolet in it.
I’m at a loss! Can’t put the top back up until I get the headrests down.
Any suggestions would be welcome.
Thanks
 
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#2 · (Edited)
FYI, enclosed are some documents, that describe the details of the roll-bar operation.

Additionally, I believe you'll find the following thread of interest.

https://mbworld.org/forums/clk-class-w208/649215-clk-430-roof-rollbar-problem.html

What were the circumstances leading to the roll-bar extending in the full up position (e.g. triggered by crash deployment which could be hitting a deep pot hole, going over a curb etc., or not)?

The fact that it took so much force to manually lower the roll-bar, even after reducing the hydraulic system pressure, suggest a possibility of a malfunctioning of the roll-bar's value block and/or hydraulic cylinder.

The cylinder is differential, meaning that it moves both ways, depending on how the hydraulic pressure is applied to the rod side or piston side, by the value block.

Either could be rebuilt by Top Hydraulics.

https://www.tophydraulicsinc.com/en/content/53-mercedes-benz-a208-info

If the roll-bar extends with a ratcheting noise, can be due to an issue with the mechanical lock of the roll bar extension actuation element (e.g. shown as item 2 in the included info.).

If the roll-bar Roll bar can not be retracted via RB switch (S83) on the dash:

Defect at RB "retracted" switch (S83/5)
Defect at RB valve block (Y57)
Defect at RB hydraulic cylinder

Note: The purpose of the RB retracted switch is to signal the controller that the RB is in the proper lowered position.
 

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#3 ·
Coil Question?

Thank you for the diagrams, they help considerably.
To answer your question; What were the circumstances leading to the roll-bar extending? Note really sure but no one was in the car when they went up. Also the top was down at the time.
I have a question about the valve coils. In the attached photo the left coil (black) is Y57Y11 Piston Side Valve and the red coil is the Y57Y10 Rod-Side Valve. When pressing the RB "retracted" switch (S83/5) in the up position the red coil and black coils are both energized. When pressing the RB switch in the down position only the red coil is energized.
Is this normal?
Does the coil move in two positions?
Could the computer be telling the coil to stay closed?
Can I switch the red coil with the black coil? To test?
(after putting the wires in the correct location)
I feel like the valve is not allowing fluid through when lowering the RB, this might explain why opening the pump bleed valve does not make any difference in the amount of force required to lower the roll bar.

Still hoping for a solution, Thanks for your time.
 

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#5 ·
Roll bar mechanical locking mechanism

The roll bar will lock when pressed down, if I press and hold the roll bar up button the two cylinders that release the roll bar mechanical locking mechanism extend and release the locks. It's only after I release the button do the roll bar mechanical locking mechanism engage and I get the ratcheting noise. So the hydraulics for the locks are working and the switch is working.
Do you (or anyone) know if I can swap the Y57Y11 Piston Side Valve with the Y57Y10 Rod-Side Valve? I'm thinking if one is bad and I switch them then the problem will to change to the raising of the roll bar not the lowering.
Are the valves bi-directional? Positive to one terminal it goes one direction, positive to the other terminal it goes to the other?
 

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#6 ·
I found it interesting that, while unintended, one day your RB extended and required manual lowering (vs. the method, using the hydraulics, as explained in your owners manual).

I believe you meant to ask if the solenoids are bi-directional and they are not. But as either is activated, by the controller, voltage is applied and internally the valve block, directionally applies pressure to the RB cylinder.

When the hydraulic cylinder is pressurized on one side, the rod extends or retracts. The direction of motion depends on whether the pressure is applied to the rod or piston side. When pressurized on both sides, the cylinder rod extends, because the force acting on the piston side is greater, due to the larger area.

To accomplish this, in addition to port seals, both the valve block and cylinder have internal seals. Unfortunately, with age, they deteriorate, but can be economically rebuilt.

I've enclosed another thumbnail, that details the operation of the valve block.

Also, these links may be helpful.

https://www.tophydraulicsinc.com/en/w208-clk/266-roll-over-bar-valve-rebuild-service.html

https://mbworld.org/forums/clk-class-w208/649215-clk-430-roof-rollbar-problem.html

https://mbworld.org/forums/clk-class-w208/649215-clk-430-roof-rollbar-problem.html
 

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