I thought I would share this story about fixing my headliner on my 2000 SLK230 because usually the stories that get shared are about brilliant results with barely any setbacks or costs. This will not be one of those stories. Learn from my mistakes.
When I purchased this SLK, the headliner was completely separated other than at the edges. I’m a short guy, and the headliner fabric was loose and balloned all the way down to touching my head. With quotes in the $400+ range on a car that only cost $4,500, I wasn’t ready to plop down 10% of the value of the car on the headliner assembly.
Let me clarify some terminology that I will be using.
– The entire assembly that makes up the fabric, backing, insulation, etc that sits above the driver’s head and separates the roof sheet metal from the interior of the car.
– The leather/leatherette surface fabric, grey in color, that covers the headliner assembly on the inside of the vehicle. (Someone correct me if this is 100% leather, I can’t tell)
– The hard board backing that makes up the frame of the headliner, and to which all other pieces are attached.
– The two yellow/black insulation-like material pads that give additional form to the headliner assembly
– A thin strip of adhesive felt used to hold the fabric to the backing along the sides of the headliner
Front Edge Trim
– A thicker piece of fabric trim at the front edge of the headliner that holds the fabric to the backing, but also is where the front three screw hole eyes give a firm anchor between the fabric and backing.
Screw Hole Eye
– Three metal eyes that help locate the screws that hold the fabric, front edge trim, and the backing to the vehicle. There are six more total screws that hold the headliner to the vehicle, three on each side, but these three are the only ones that are easily visible during operation of the hardtop, so they are dressed up a bit.
The first step was removing the Headliner from the vehicle. Nine total phillip head screws did the job. Three on the front edge and three more each on the sides. I’ll let the detailed instructions
from Pelican Parts explain.
Can we just stop for a second to admire the craftsmanship in this headliner assembly? Upon closer inspection, this headliner appears to be genuinely hand made of quality materials, only let down by an adhesive that couldn’t handle a certain count of heat cycles.
Glue is going to do the lion’s share of the work holding the fabric to the backing, but along three edges there is supporting trim, and along the back edge, your work will disappear into a trim piece that holds the back edge of the headliner in place. So don’t be too bent out of shape if your fabric isn’t perfectly aligned along the outer back edge.
Back Edge Will be Hidden.JPG
With the headliner out of the vehicle, I popped out the grey plastic button and removed the three screw hole eyes and set them aside with my nine screws for later.
Throughout the process, I would also leave the two larger pads in place. These pieces didn’t need to be removed and had no damage or failure.
My next step was to remove the fabric from the backing. I began with the edge felt on both sides. I ran a fresh razor blade carefully along the edge. This left me with a thin strip of adhesive felt still remaining on the backing, and another on the fabric. I would (later) carefully remove all that old adhesive felt from both surfaces. There is about 20” of felt on each edge, it’s about 1” or so wide.
Side Trim Removal.JPG
Continue with the careful cutting all the way to the point where the edge felt ends. There are a few tiny squares around the corner along the front which also need to come off.
Side Trim Removal 2.JPG
At this point, the only part holding the fabric to the backing should be the front edge trim. Go ahead and peel that off next, it’s only held on with glue.
Front Edge Remaining.JPG
You can see the reinforced nature of this front edge trim piece compared to the basic adhesive felt along the sides. I chose to reuse this front trim piece, but I scrapped the edge felt, there was no way the edge felt could be re-used, or removed without destroying it. The front edge trim remains on the fabric, but comes off of the backing.
Front Edge Closeup.JPG
At this point I now had separated the fabric from the backing. Both had old, crumbly, barely tacky, 20-yr old adhesive on them. I knew from other threads that I could take this fabric to a store, or make a pattern from it and get the fabric cut to my specs. But upon inspection, I felt that the original fabric was in really good shape. Because the edge-curl at the front was so specific I felt it was going to be really difficult to take a fresh piece of fabric and get it to form to the backing the way this one already was designed to do.
I decided to attempt to re-use the fabric. I started scraping the old adhesive off, and it worked extremely well. The resulting surface didn’t come off under hand scraping, or ball up, so I felt like I’d got down to the surface to the point where it would take to new adhesive.
Here’s the same surface after much scraping.
Compare to the yellow mess in the previous picture.
It was also at this point that I removed the remaining edge felt from the fabric. It came off fairly easy, by hand, once I had my technique down for rolling it off. I think with the wrong type of tearing action, one could easily damage the fabric at this point.
Now it was time to tackle the backing. It also had a ton of aged adhesive on it.
Because this was a much stronger surface than the fabric, I thought I could take a power sander to remove the old glue. This wasn’t a great idea! The mechanical action did get the loose bits of adhesive off, but they didn’t do a much better job of prepping the surface than just scraping diligently by hand with a brush. I ended up doing ˝ of the backing with each method for comparison.
By this point I had two very clean surfaces. The backing, especially, really came free of old adhesive. But I couldn’t re-use the side felt. I attempted to source some adhesive-backed grey felt. I know Mercedes dealers stock an MB SKU for the black adhesive-backed felt, but I wanted grey. The local JoAnn Fabric superstore didn’t have it, so I settled for standard grey felt, cut to 1” strips. The plan was to “soak” the strips with a generous amount of adhesive so that they would function the same as the original side felt. This was probably a mistake – go get yourself some legit strips of adhesive-backed grey felt!
I also sourced 3M Premium Auto Headliner Adhesive. This stuff ain’t cheap! But I remember this is what we used at the Mercedes Benz dealers when I worked there, and I’ve read a ton of bad stories on the internet from people who had headliners fail with other adhesive products.
THIS IS WHERE THINGS WENT OFF THE RAILS.
I was really quite proud of myself at this point. Everything looked really good, and I was ready to spray my adhesive on to both the backing and the fabric, get things in place, and finish things up.
I tested the fit of the fabric to the backing and it felt a little small. I thought that perhaps it had shrunk up a bit with the temperature, so I put the fabric out in the sun to see if it wouldn’t get a bit more pliable.
I got everything in place, had my felt pieces cut to size, and started applying 3M adhesive to the backing and to the fabric.
It was a huge challenge to maneuver the fabric against the backing, especially along the front lip, without getting adhesive (which was immediately all over my hands) all over the “good” side of the fabric. Even if I’d had two sets of hands, this would have been difficult. I think maybe this is a good job for an octopus.
As I tried my best to get the fabric lined up, while also not getting adhesive all over the “shiny” side of the fabric. I also used a large plastic scraper to push out the bubbles. This was all in vein. The 3M adhesive sections got super tacky, super fast, and created full adhesion, with bubbles still in place, despite my best efforts to flatten them out.
I did put some clamps in place to hold the side trim in place, and the adhesive soaking did a good job making everything on the edges stay in place – but it also didn’t look great due to imperfect edges and sizing. *sigh*
Perhaps someone with real upholstery experience can give some tips to not screw up this step.
The result is something that meets the absolute lowest bar – the headliner now stays off my head. So, this is some tiny measure of success. But it doesn’t look great.
I will say this about the 3M Adhesive – it’s not letting go. It’s 100% holding in place (where it’s not bubbled) and it’s been like this now for about a month. At this point, I think I’m going to wait until the cylinders leak and ruin this headliner fabric, and I’ll try it all again, with improved technique(?)
One Month Later.JPG