Fixing a Loose Airbox


Autocross Champion
New Jersey
2016 Golf R
I recently purchased my car and while going over it with a fine tooth comb, I found the Airbox was loose. Like really loose. So I pressed down on it to resecure it and it was still floppy. A little further inspection revealed the pins that hold the Airbox to the battery tray were broken. I was going to buy a new battery tray, but decided to just fix it for free.

So here is a before. I was rather annoyed by this. I assume the prior owner had a cold air intake in it and damaged them.

Here is what I had left. I tried to use a plastic "welder" adhesive on the side. I have used it in the past with really good success, but it wasn't happening this time.

Broken Pin Front.JPG

Side bin broken.JPG

So I grabbed what remnants I had of the original pins and took a few measurement and threw together a quick sketch in FreeCAD. Sent the file to a buddy of mine and he printed them up. I figure the design is very intentional, being German and all, but I said to hell with it and just made them solid. 100% infill as well. I wanted these to be stout.
Both Pins.JPG

From there I wanted to test fit everything, I already had a pretty good idea of how this was all going to work. I needed to trim the remaining bases off of the tray. I used a little piece of hacksaw blade I made for tight areas. Cut right through. While I am not a fan of the scratching, you will never see it.

Front Pin Saw.JPG

All cleaned up and ready to test fit.

Front Pin Removed.JPG

I went ahead and test fitted to make sure the base was going to fit.

Side pin fitted.JPG

Perfect fit. I didn't know if the notches on the head were functional, so I went ahead and cut them in. I didn't measure, the front pin was missing completely and I misplaced the head of the side pin. I eyeballed them the best I could and went for it.

Front Pin Cut.JPG

Hardly perfect, but still functional. It was just a matter of inserting the brass thread into the bottom.

Front pin bottom I.JPG

I designed the pocket to accept this fitting. These just heat press in. Pretty simple, but very effective.

Front Pin Threaded.JPG

It was just a matter of hardware form there. I used a short M5x.8 bolt with a fender washer to secure it into the tray. I tried designing one pin for both positions, but the height matters. So I needed to design a different height piece for the front pin.

You can see the same pins here, didn't work.
Wrong Pins.JPG
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Autocross Champion
New Jersey
2016 Golf R
Here are the correct pins in the correct locations.

Both Installed.JPG

and the best part one solid airbox

I am pleased that this worked as well as it did. I may try and go back and do a better version. The post could be about 1mm taller and I would like to try and have it print with the notches in them, to save me a step. I may also make the head a little smaller. Overall, very pleased with the results.