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Old 02-25-2018, 03:16 PM   #1
wc123wc
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Join Date: Sep 2011
Location: Toronto
Posts: 262
E39 Gas cap door [SOLVED]

Lately I noticed that the gas door (the metal flap that covers the gas cap) is not closing in properly. I inspected the reason and found out the gas cap holder (the green plastic piece that holds the gas cap when filling gas) was hitting the gas cap so the gas door never closed in all the way.

I researched for solutions and here are some answers:

1) The gas cap spring is broken and I needed to buy a new gas cap. It's suppose to click when you lock it CW and after the click it's suppose to spring back a bit CCW, and the reasoning is that once it turns a bit CCW then it won't interfere with the gas cap holder.
This might be the problem for some, but before you go and buy a new gas cap clean the gas cap you have and spray it with silicone lube or WD40 to make sure the spring is free to move.
My gas cap already clicks when locked CW and springs back CCW but it was still interfering with the gas cap holder, even after I cleaned it and sprayed it with silicone lube.

2) The gas door is misaligned because of previous body work, etc. Mine looked perfectly aligned so I didn't mess with that.

3) The spring on the door is old and needs replacement. May be, but from my research everyone says it's pretty weak on the E46/E39, so I wasn't sure buying a new spring would solve the problem.

4) I decided to move the gas cap holder either to the side (toward the inside) or up by few millimeters. If I move it to the side then I have to redesign it and 3D print it which I could but I didn't feel like spending that much time on redesigning it and 3D printing it.
So I decided to modify the existing part to move it up by 3mm.

Here are the steps I took which solved the problem for me (see the images); now the gas door closes in all the way.

Step 1: Take the gas cap holder out and clean it (I used nail polish remover).
Step 2: Shorten the middle flange by 3mm.
Step 3: Reduce the two side grooves by 3mm.
Step 4: Reinstall the gas cap holder.

The whole thing took me 30 minutes and now the gas door closes in all the way.

I hope someone finds this helpful!
Attached Images
File Type: jpg E39 Gas cap cover 1.jpg (167.1 KB, 29 views)
File Type: jpg E39 Gas cap cover 2.jpg (178.8 KB, 29 views)
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