Front Wheelhouse & Fender Liner Screws

[puchak]

I figured it could be useful for all W124 owners as the design is similar.



If you take your wheel off, you should see a bunch of nuts screwed in all around the wheel arch. This holds the fender liner, if you take those off, you will see there are screws that come from the structure of the car. If your W124 has seen a lot of miles, I highly recommend checking this area. The nuts can get loose, the screws can rust, and a lot of organic garbage can accumulate in there which can lead to more rust.

If you have misplaced your nuts holding your liner, this is the part number: 201-990-00-50

Here is one of mine up close:



With that said, I've taken my liner and fenders off on my 300TE and found that one of the screw is completely broken!

• You can't reach the other side of the screw. It seems to be between the arch and the engine frame.
• I don't believe it was welded in. My guess is a riv nut or captive stud.

So, I'm curious if anyone knows of any solutions or has dealt with this before. Replacing these screws could be very important preventative maintanence, especially on higher mileage vehicles.

 

[puchak]

Ended up drilling a hole where the screw was originally welded and put a tapper and tightened it with the fender liner nut. Only downside is I have to hold the tapper when I tighten the liner nut.

I also found out that Mercedes offers this very weird and overpriced rivnut looking piece. Doesn’t look like it can bend or be riveted. Does anyone have experience with it? My guess is you still cut a hole then tighten it from the inside.

P/N: 0009901210

 

[sheward]

It looks to be a design where you insert it into a hole and then use a bolt to pull the back against the front. Think of a pop rivet with threads. A type of rivnut? These can be found at good hardware outlets. I won't ask what MB charges for them.

 

[gsxr]

Yep, looks like a Rivet Nut with a fancy insert. MB wants $20 each (discount) which is in-sane. Gotta be a way to buy the same thing elsewhere! I could use a few of these, but not at that price.

 

[GRAEME JOHNSON]

Thats a smart looking repair rivnut but what a price
I have a couple of these sheered off on my R129 ,I just belived
the threaded studs were welded on. I will have to have a better look
As someone else said in one of the how to posts it might be better to
cut the plastic nuts away from the studs with a dremell and disc rather
than try to undo them and shear the stud.
The plastic nuts are cheap
Graeme Johnson

 

[500AMM]

I guess those fender liner bolts are stud welded. The enclosed image is not the correct studs, but just to show how captive studs for welding looks like. A body shop at a larger scale will have a resistance welding machine in house, and they may also have a stud welder, it's not that complicated to do this.

As for the licence plate rivet nuts. I once replaced one on my first 124. It is aluminium and MB use a special rivet tool, looks like a regular rivet tool but with a metric bolt pulling the rivet tight, it was a quick fix. The hardest part was actually to drill out the old nut, because it start rotating as soon as you start drilling. And keep in mind that the hole in the chassis originally is hexagonal.

There is several types of the licence plate rivet nuts, the most common are on the enclosed image. The one at right is the one listed for the 124, but I recall using the longer type. It depends on the clearance at the backside. The one at left has a thinner flange and would probably be the best replacement for the fender liner bolts. But keep in mind that these rivet nuts are aluminium and sitting in the harsh conditions inside the wheel house, they will be eaten over time. Covering completely with thick body sealer will help though.

Anyway, @puchak, don't drill additional holes for this in the chassis/panels - find someone doing stud welding. And regular metric studs with washer & nylock nuts will make it as well, probably better than the plastic nuts.

 

[GRAEME JOHNSON]

They sometimes use coarse studs like that to pull out dents
Next time I am at my friends body shop I will put one in a vice
and try one of the plastic nuts for size
Graeme Johnson

 

[puchak]

Anyway, @puchak, don't drill additional holes for this in the chassis/panels - find someone doing stud welding. And regular metric studs with washer & nylock nuts will make it as well, probably better than the plastic nuts.

Unfortunately, I already drilled the one hole that was very top and center. It sits under a bunch of cables in the engine bay so it isn’t visible. Down the line I think I will have it stud welded, granted it isn’t a huge hassle with the hole present.

I would say the next most valuable bit of information at this time would be what screw closely resembles the OEM one?

 

[MercEdi]

A0009902913 or 000-990-29-13 should be the studs you are looking for.

 

[500AMM]

A0009902913 or 000-990-29-13 should be the studs you are looking for.

I checked that PN and among others a link to a Russian page popped up, but I'm not sure it's legit.
However, I copied the sketch & table with various PNs, it may give a lead.

 

[GRAEME JOHNSON]

I went to see my friend but he only had thin smooth dent pulling pins (pictured)
The items in the above posts look to be the correct items
Graeme Johnson

 

[gsxr]

A0009902913 or 000-990-29-13 should be the studs you are looking for.

000-990-29-13 may be for a machine threaded stud, M14 x 1.5 ... ??




There is conflicting info in the EPC for 000-990-29-13: Probably need to order one of each and see what show up.

 

[500AMM]

Dave, I noticed that as well, and based on a picture coming up it looks like the wheel lugs pressed in the wheel hub flange.

It is confusing that this PN (A000 990 29 13) is listed as a replacement in that table I posted above (post #10) - a replacement for that coarse threaded 5 mm welding stud..?? Must be something wrong in that table, but it does at least list those welding studs.