A4 Avant license plate mounting

[Kent McLean]

Michael McLaughlin wrote:
> If anyone can give me some insight into how the plate mounts to the back 
> of an Avant, I'd appreciate it. 

Here is a write-up I did for the Audifans KnowlegeBase.
Forgive the formatting, it's Wiki for the KB. And it's
not in the KB yet, as I've been I've been having trouble
adding things to the KB.  It was written for my '94 100,
which uses a plastic trim plate which is screwed and
glued to the body. The captive license plate nuts are
secured to the plastic trim. For an A4, YMMV.

Cheers,

Kent McLean
'94 Audi 100 S Avant, V6-12v FWD automatic
'89 Audi 200 TQ, "Bad Puppy"

--- cut here ---

---++Avant Rear License Plate Nuts

This is a simple and cheap fix for the captive nuts that no longer hold 
the rear license plate on a (US model) 100 Avant.

On a scale of 1 (easy, like replacing a light bulb) to 10 (difficult, 
like rebuilding an engine), I'd rate this a 3.

     * Time: 1 hour
     * Cost: US$5

---++++The Problem

The original captive nuts are only 1/8" thick, have a sheet metal 
backing, and abut the tailgate sheet metal. They are set into a black 
plastic trim piece.  If the bolt rusts into the nut, trying to remove it 
will cause the captive nut to turn, damaging the trim piece. Damage will 
also occur if a bolt that is too long is used to attach the license 
plate to the car. The bolt will bottom out, then cause the captive nut 
to turn, destroying the plastic trim piece. Once the nut turns, it will 
no longer hold the license plate.

The fix is to remove the trim piece, remove the captive nut, fix the 
damage, and replace it with a new fastener.

---++++Disclaimer

%X% The instructions given here worked for the author; however, your 
results may differ. The author and the owner of this web site accept no 
responsibility for any damage that may occur to you or your car based on 
these directions.

---+++Parts

    * license plate nut(s) [Note: I got mine at the local hardware 
store. They are nylon or plastic nuts that push in through a square hole 
and expand when a bolt is screwed into it, like a wall anchor. I think 
the square part is 3/8", which fits the Audi hole perfectly. See picture 
below.]
    * license plate bolt(s), to match the captive nuts
    * 60-second 2-part epoxy glue (in Siamese-twin tubes)
    * all-purpose adhesive/caulk

---+++Tools

    * medium crosshead (Phillips®) screw driver
    * medium regular (slotted) screw driver
    * pliers
    * mild detergent or other cleaner

---+++Directions

1. Remove the license plate

    - Unscrew the 4 screws that attach the license plate to the frame.
    - If a screw refuses to come out because the captive nut rotates, 
use a pair of vise grip pliers and pull it out. Don't worry about 
damaging the plastic frame; you will fix it later.

2. Remove the plastic trim/frame

    - Unscrew the 2 cross-head bolts exposed when the license plate was 
removed.
    - The plastic frame is also secured to the body by some black 
adhesive. It is applied to the horizontal indentations running across 
the frame about 1/4 of the way in from the top and bottom edges.
    - Get a finger under the left or right bottom corner, and gently and 
evenly pull on the trim. It should slowly come loose from the sheet 
metal. Don't pull too hard or too fast, or you may break the plastic 
trim piece.

3. Remove the captive nuts

    - Remove the tape that prevents the captive nut from chafing the 
painted body panel.
    - Use a pair of pliers to pull the captive nut out from the back 
side of the frame.

4. Clean up things

    - Peel the black adhesive off the plastic trim piece. I used my fingers.
    - Use a mild detergent to thoroughly clean the plastic trim piece.
    - You should also clean the body panel that was exposed when the 
trim piece was removed.

5. Fix the damage

    - On my '94 Avant, only one hole was enlarged so as not to hold the 
captive nut. My repair involved using epoxy glue to glue the new captive 
nut in place.
    - I inserted 4 new nylon license plate nuts into the trim piece (see 
picture). I pushed the nut in from the face of the trim piece, so the 
nut would expand behind the panel.
    - I secured the license plate to the trip piece and new captive nuts 
with the new screws.
    - The nut in the damaged area floated free. This is the one that 
needed repair.
    - I mixed a small dollop of epoxy glue according to the directions, 
and applied some to the loose captive nut. I didn't try to fill in the 
hole at this time, but just tried to secure the nut in place.
    - I let the 60-second glue dry for 20 minutes.
    - Repeat the epoxy glue repair process as needed, apply thin layers 
until the damage is repaired. Let it dry overnight.

%T% Note: while I had the trim piece free, I used a bench grinder to 
shorten the license plate screws so they would not exceed the depth of 
the captive nuts.

6. Secure the trim piece

    - Apply a thin bead of all-purpose adhesive/caulk to the raised 
ridges on the back side of the trip piece.
    - Position the trim piece in place.
    - Secure the trim piece with the 2 cross-head bolts.

7. Secure the license plate

    - Attach the license plate using the (shortened) license plate screws.

---++++Summary

Stand back and admire your work.

If you used nylon or plastic nuts, you should prevent the problem of 
rusted bolts tearing the nut out of the plastic trim. And using short 
bolts will prevent the captive nut from turning, too. (Long bolts will 
dig into and mar the sheet metal behind the trim.)

-- <a href="/cgi-bin/twiki/view/Main/KentMcLean">KentMcLean</a> - 18 Jul 
2004