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2005 SLK55 AMG /2005 SLK350
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Discussion Starter · #1 ·
My 98 is having some difficulty with the boot lid. First off, it doesn't appear to close smoothly. The last inch or two it doesn't lower on the left side smoothly. Then it kinda bumps into place and closes. When the lid comes up there's a pretty loud pop. I think the tongue isn't mating with the latch on the left hand side - the tongue is a little too far forward. Also, the tongue doesn't always seem to trip the switches - it's like the tongue isn't always going far enough into the latch. Sometimes it does, sometimes it doesn't.

So I'm thinking I need to do a total re-adjustment of the boot lid. Has anybody here done that before? I'm wondering what's the best order to adjust the items below.

- The hinges at the rear of the car that secure the tubular frame to the car.
- The mounting of the boot lid to the tubular frame.
- The attachment of the tongues to the tubular frame.
- Any other adjustments of the tubular frame.
- The mounting of the latches to the wheel wells.
- The attachment of the diagonal ski-slopes and the two stops.
- The yokes on the cylinders.
- The cables between the cylinders and the latches.
- The left and right height adjustments for the boot lid.

Anything else I missed?
 

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*Premium Member
2004 SLK200K
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10,777 Posts
Have you thought about removing the side panels, putting a light inside and then recording a video inside at various angles, with your phone (or whatever), whilst slowly closing the boot lid, it might give you some good ideas what to try ?
 

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*Premium Member
2005 SLK55 AMG /2005 SLK350
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Discussion Starter · #3 ·
All the panels are currently out, including the steel panel that covers the hinges for the tubular frame.

I've been watching with the trunk lid open (by opening the trunk in the usual manner and tripping that latch with a screwdriver -- the roof module thinks the trunk is closed and thus allows operation to continue normally).

The behavior changes somewhat when the trunk is open, so I'm thinking the boot lid itself may be part of the problem - or just need adjustment itself.
 

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*Premium Member
2005 SLK55 AMG /2005 SLK350
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6,187 Posts
Discussion Starter · #4 ·
I improved it dramatically by adjusting the tongue on the left side - two bolts. It was not aligned with the latch 100%. I adjusted it once, but I didn't tighten it enough the first time and somehow it went back to the previous position. After re-adjusting and re-tightening a little tighter it seems to be working better now, and staying.
 

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*Premium Member
2005 SLK55 AMG /2005 SLK350
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6,187 Posts
Discussion Starter · #5 · (Edited)
OK - more info.

Unfortunately, after two weeks the popping returned. I didn't use the roof much during that time. Foolishly, I replaced the latch with a new one yesterday - didn't help at all. My previous alignment of the tongue was still intact.

I made two videos from inside the trunk, left and right side. You can clearly see and hear some disturbances on the left side.

https://youtu.be/scJMLaMKWKU

https://youtu.be/AsGsps-QesQ

You can also clearly see and hear the popping is related to the motion of the cable.

My current theory (subject to change of course) is that the left cable was still not tight enough. I don't believe the procedure to adjust these cables is documented anywhere, so here goes... please add your comments!

Before you start:

- There are two release cables for each latch: 1) the bowden cable connected to the bottom of the cylinder, and 2) the looped emergency release cable.
- The bowden cables have a tension adjustment at the cylinder end. Note the current setting before you start (in case you want to get back there).
- The fork-like cable attachment on the bottom of the cylinder bends quite easily. I'm not sure if this is a safety feature or a manufacturing flaw. Mine was bent pretty bad, so I bent it back to it's "natural" position.
- The two latches are spring-loaded and can be manually set (latched) and tripped (unlatched).
> Set them by pushing in with a small screwdriver or L-shaped pick, and
> Trip them by pulling on either cable.
- You should familiarize yourself with manually setting and tripping them before you start, and be sure to leave the latch tripped when you're done (before you operate the hydraulics).

Here's how to adjust the bowden cables:

- You have to adjust each side independently,
- Adjust them with the trunk lid in the assembly position (i.e. tipped back and then opened forward, the lid will be floating high in the air).
- In this position:

> The cylinder has about 1" of play "up and down" thanks to the slot at the bottom,
> Correspondingly, the lid has about 2" of play "back and forth",
> Have a helper slowly move the lid back and forth and watch what's happening.

- You'll notice that the bowden cable draws and releases as your helper moves lid.
- For adjustment purposes, familiarize yourself with the following:

> Push the lid rearward to the limit of play,
> Manually set the latch,
> Slowly push the lid forward until the latch trips,
> You might want to watch what's happening at both cable ends while you do the above,
> You definitely want to hear and see the latch trip. If it doesn't trip, your cable may be way too loose to start with, or hopelessly stretched.

- (Edited) Adjust the cable tension so that the latch trips just before the lid reaches the forward limit of play.

> If the latch doesn't trip at all, you need to tighten the cable.
> If you can't set the latch, you need to loosen the cable.
 

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*Premium Member
2005 SLK55 AMG /2005 SLK350
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Discussion Starter · #6 ·
Here's another video I made of the bottom of the left-hand (US driver side) boot lid cylinder. The roof was fully closed when I made this video. I simply started opening the roof with the button. I stopped after just a few seconds.

https://youtu.be/BRBdi2rHUSw

You can see how the cylinder extends and draws the bowden cable tight. But what's confusing to me is why does the cylinder reverse direction afterwards? The only explanation I can come up with is the other (right-hand) cylinder is extending faster/further than this one, raising the roof, and the roof is pulling up on this cylinder.

I'm wondering if the yoke atop this cylinder needs to be extended.
 

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*Premium Member
2005 SLK55 AMG /2005 SLK350
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6,187 Posts
Discussion Starter · #7 ·
I edited my previous post to add some new information. I've adjusted this roof in so many ways... To the point where it was aligned and quiet - but the side latches wouldn't close fully enough to close the switches. Today I worked a little more on it and I learned a good trick. I found that raising the lid to the assembly position and temporarily engaging the center latch with a small screwdriver allowed me to operate the roof with the lid open. I could see things much better (although my daughter wasn't thrilled sitting in the car pushing the button while I watched).

Interestingly, with the lid in the assembly position, the side latches will fully engage! So I think my remaining issue is to adjust the lid itself.

I'm wondering if I'm missing some shims between the frame and the lid. Of if the partially shattered plastic buffers in the rear need to be replaced.
 

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*Premium Member
2005 SLK55 AMG /2005 SLK350
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Discussion Starter · #8 ·
I'm not sure if #41 is 1) a spacer between the striker and the tubular frame, or 2) the nuts that fit behind the tubular frame. Does anybody happen to have a picture of theirs?

If it's #1 , mine is missing, and might well account for the difficulty closing.
 

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*Premium Member
2005 SLK55 AMG /2005 SLK350
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6,187 Posts
Discussion Starter · #9 ·
I made videos of the two boot lid cylinders during operation - it clearly shows the RHS operating faster than the LHS. They're not even close!

I used two webcams on my laptop and an app called manycam to record their movement simultaneously.

My current theory is the different speeds is what's causing the LHS to behave as it is; I'm considering rebuilding the LHS. Does anybody have any experience rebuilding these cylinders?

 

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*Premium Member
2005 SLK55 AMG /2005 SLK350
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6,187 Posts
Discussion Starter · #10 ·
I've decided to send out these two cylinders for rebuilding. They are not quite as easy to disassemble as the other three cylinders, I'm not optimistic I could do it myself successfully. Hopefully they'll be back in a week or two and I'll post an update.

I swapped the hydraulic lines left vs. right, and the LHS cylinder remained slower than the RHS. In my mind, this rules out the pump (and I had the pump rebuilt recently anyway - a total waste of money in hindsight). I also operated the lid with the cylinders disconnected from the frame, and it operated very smoothly and properly. In my mind, this rules out the mechanical components. And finally, I fabricated a gauge to confirm the latches and the tubular frame were square - this rules out the car having been damaged due to accident.

On the "different speed" issue, I noticed another interesting fact when preparing for shipping. I pushed and pulled on the ram by hand to evacuate the fluid, and initially the LHS cylinder required much, much more effort to do so. However, once the fluid was out, it got much easier, with no real difference between the LHS and RHS cylinders. So I'm thinking a blockage is what accounts for the different speeds - either in a hose or inside the cylinder itself.
 
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