My w208, 2002, clk 430 cabriolet has a problem when I try to open the roof it pops the back roof lock as it should and the back cover starts to open for the roof to fold in but just as the little side flaps start to open it all stops and then the rollover bar raises itself and the ratchet clicking sound is heard.
All worked ok before this.
I viewed many threads and did the following in this order.
With the roof manually put down and fully stowed I Took the back seats out, loosened the hydraulic screw in the trunk, pressed both pawls back with screwdrivers while friends pressed the heardrest down until they clicked. All good they went down, and I re tightened the hydraulic screw.
I then Pressed the rollover bar switch to test raise the headreast and instead of hydraulically going up the spring forced ratcheting took over and raised them and they were stuck back where I started.
Repeated the procedure and then once headrest were down I manaully raised the roof, re tightened the hydraulic screw and this time just went straight for the roof button to test if it would open. Again it started ok but when it got to the point where the little side flaps are supposed to open it stopped and the spring lifted the headrests.
I have not removed panels from the trunk area yet so don't know what the fluid levels are like.
To me it seems like something is causing the headreast spring to raise, which then means the roof won't work.
Any ideas would be greatly appreciated

 

When a roll bar extends independently, with a ratcheting noise, that is not triggered by a pending situation detected by the crash deployment sensors, may due to a malfunctioning roll bar deployment lock (a.k.a. 7).

In our A208, the lock engages by a roll bar deployment solenoid (a.k.a Y57/1) which is actuated by the roll bar / power roof controller (a.k.a. N52).

I have enclosed several thumbnails that identify the referenced components mentioned above.

As example, if Y57 malfunctions, the increased hydraulic pressure due to opening the roof, can release the locking pawl. Additionally, this would also trip the roll bar extended switch (a.k.a. S83/6) and stop further operation of the power roof.

Please note that the aforementioned is not an end diagnosis of your problem, but just a suggested area to further troubleshoot.

 

Thanks Serndipity I'll have the components you mentioned checked next week and report back.

 

Ok it going into the mechanic today, will post details soon

 

Another possibility for a malfunctioning roll bar deployment lock (item 7) is that, after it manually extended and then lowered manually, the sides of RB became tilted.

In order to prevent this, during lowering and raising, there is a synchronizer shaft (item 30), which s connected to both sides of the RB, to keep the gearing and pinions properly aligned.

Normally, after cash deployment, the RB can be lowered via the RB switch on the dash, first by raising the RB until a click is heard, followed by lowering. The click is the pinions being initialized to the correct starting position.

If this procedure fails to lower the RB, it has to be lowered manually, which is not only a PITA, but can result in tilting, if even pressure is not applied to both sides.

When the pinions are not properly synchronized and engaged into the gears, the crash deployment lock may not be securely set.

 

My mechanic says the fault code is for what he calls the valve lock, which he says is the same part Serndipity refers to as the rollbar deployment solenoid, dealer cost is around $3000aud , or overseas supplier is around $2000aud......ouch. He says he doesn't know anyone in Australia that successfully rebuilds this part. He recommedns to try find a second hand part. He also thinks the pressure may be low so no guarantees a new solenoid will fix the problem....Looks like I might be operating the roof manually for a while. Oh well I drive it with roof down most days anyway and park it undercover.

 

just saw an old thread from klaus suggesting to someone that they take the connector off the right solenoid on the rollbar valve, and then the rollbars might not work, and therefore might allow the roof to work, that thread seemed to be a differe my problem where bars went up unstated of down, but I might try this with my mechanic next week anyway.
Any other ideas on how i might disengage the rollbar mechanism , in an e fort. to make the roof work would be great to hear, sounds crazy but I'd rather have a working roof than a working rollbar, if it works I'll just sit low, strap in tight and try not to roll the car.....

 

Here is the U.S., MB does not provide individual RB replacement components and will only sell the entire RB assembly at $$$$$$, as well.

It's beginning to sound like the erroneous RB crash deployment is being caused by a faulty value block (Y57) or RB hydraulic cylinder (e.g. leaking internal seal).

See http://www.benzworld.org/forums/r129...down-when.html for additional information.

If so, fortunately, Top Hydraulics can rebuild these and has numerous happy international customers.

 

I have a 2003 CLK430 that has a similar issue where the rollbars are stuck in the up position. There are no leaks anywhere and the pump is working. When I try to reset the rollbars using the switch on the dash it actuates the rear lock but doesn't release. Is the most common cause a defective rollover bar valve Y57 or #1248001678 or can the control module N52 be the culprit?

In Blvd430's post, he mentioned pushing down the rollbars manually by releasing the pressure and pressing on the pawls "loosened the hydraulic screw in the trunk, pressed both pawls back". I'm assuming the hydraulic screw is the one on the hydraulic Cylinder Item #2 in the first thumbnail provided by Serndipity but where are the pawls located? Thanks in advance for any help provided.

 

I'll have to remember exactly what my problem was - I think a roll bar switch. The dealer said it can't be replaced without replacing the entire roll bar, but I did research and found that an older model SLK (maybe) switch would work and it did. I spent like $45 on the fix. It doesn't sound like the same problem you're having, though.

 

sequelman.....

I've included a couple WIS thumbnails that further explain the roll-bar crash deployment mechanism, location of the components etc.

Also, the following link has numerous additional details and pictures pertaining to lowering the roll-bar manually.

https://mbworld.org/forums/clk-class...ml#post6588920

 

Serndipity ,

I can't believe I missed the pawls when I had the back seat off, probably was so frustrated at that point I couldn't see anything. I will give Aussiesuede's instructions a try this weekend. Thank you so much for all the information.

 

Serndipity,

I followed the steps in Aussiesuede's post and used some wood shims to hold the pawls in the open position but I was still unable to lower the headrest/rollbar. I also noticed after tightening the screw on the pump that then when I press the button on the dash to lower the rollbar the pawls are opened by the hydraulic actuators on both sides. Is it possible that the issue is with Y57 or the Hydraulic Cylinder item #2 is bad and not releasing pressure thus not allowing the headrest/rollbar to go down?

I just checked again and it doesn't seem to matter what position the pressure relief screw is on the pump, fully open or fully closed, the pawls are released when I press the button on the dash. I know that the pump will release pressure because I manually lowered and raised the top to see if that would reset everything and I had to turn the screw counter clockwise to be able to do that. I couldn't even budge the top when the screw was in the closed position. Just seems weird that the hydraulic actuators that control the pawls activate either way.

Thanks

 

sequelman.....

Excellent observations (e.g. seems that there is some unusual hydraulic pressure, that is applying a resistance, which is preventing the roll bar from lowering, either manually or hydraulically).

In general, when the roll bar can not be retracted via dash RB switch (S83), the possible causes can be:

Voltage supply to Power Soft Top Control Module (N52)
Defect at RB switch (S83)
Defect at RB "retracted" switch (S83/5)
Defect at RB hydraulic unit (power soft top) (A7/5)
RB valve block (Y57)
RB hydraulic cylinder
Fault at Power Soft Top Control Module (N52)

Unfortunately, the MB STAR diagnostics will only provide 4 DTCs (diagnostic trouble codes) pertaining to the roll bar.....specifically:

B1000, which indicates a malfunctioning N52 controller.
BI647, which indicates a malfunctioning pump.
BI648, which indicates a malfunctioning RB deployment solenoid (Y57/1)
BI650, which indicates a problem with the RB retracted limit switch (S83/5), due to either supply or signal voltage.

Additionally, MB does not sell roll bar related replacement parts (e.g. when a RB fault is diagnosed, the only dealer solution is to replace the entire assembly, at a cost around $6,000 + labor.

Fortunately, the switches are the same as used on the R129, which MB sells separately and Top Hydraulics can rebuild. as required, either the RB cylinder or value block.

While many of the conditions, pertaining to the controller, solenoids, switches can be checked using a multi-meter at the N52 connector, from your observations, at this time, would suspect a problem with the RB lift cylinder or
value block.

The hydraulic cylinders used on the W208, are 'differential' (e.g. move both ways, depending on how pressure is applied by the roll bar valve block).

One thing I want to mention is that while faulty (e.g. leaking) hydraulic cylinders usually appear as leaking end seals, that's not always the case, as differential cylinders sometimes fail due to crumbled internal seals, which can block in/out ports.

To assist further, I've included another thumbnail, that further explains the operation of the RB value block, which is where I would further troubleshoot.

 

Serndipity, thanks for the additional information. I sent the valve out to Klaus at Top Hydraulics and he was awesome to deal with. The Rollbars now come down, I just need to bleed the system and make sure the top goes up and down.

Thanks again.

 

sequelman.....Wonderful news!!!! Give yourself a big pat on the back.

No need to bleed the hydraulic system, as it will self bleed during a couple of power roof operations. Just top of the fluid, if necessary, prior to buttoning things in the trunk up.

Yes........we cabriolet owners are very fortunate to have Klaus's knowledge and support.

 

I got sidetracked with other cars for a while and have been operating my roof manually as it's still not fixed, im going to review these posts again and get my head around it all and have another go at it over the next few months and send my y57 to klaus.
sounds liked its worked for sequel man, still loving the 24 valve v8, even if the roof is a PITA

 

 

 

Do you have part numbers for the replacement orings you purchased?

 

No there is no part number that im aware of. I took the valve block into a seals supplier and he took measurements and had the seals