CTS-V fuel filler retainer bolt fix

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kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

CTS-V fuel filler retainer bolt fix

Post by kevm14 »

I broke this bolt back in 2011 when I did the stainless braided brake hoses. I thought I might be able to move the fuel filler out of the way to help with the hose job (which was quite unpleasant). The very first thing I tried was to remove that retainer bolt which holds the fuel filler snug against the inner wheel well area, and out of the way of the wheel motion. Well that bolt promptly snapped off. Then I realized the filler was still quite firmly in place even without that bolt, so I never bothered to fix it.

Just this morning I decided to run the right rear tire down to my local shop to have them reseal the bead (this is the worse of the two, between this one and the front passenger side tire). After I got back I figured it would be a good time to finally tackle this job and put a bolt back in there, so the filler is restrained per factory.

The first thing I did was attempt to drill the hole out. This resulted in a broken 3/16" drill bit, and then a broken 1/4" drill bit. I could pretend the car is made from some amazing material (and I guess that's what you would read on some German car forum) but in truth I was just drilling at a funny angle because the brake caliper wouldn't quite let the drill get perpendicular with the hole.

I can't even remember the last time I broke a drill bit and it would have been a tiny one.

Broken bits:
S7302599.JPG
Finally I decided to try a large 5/16" bit, which seemed to be the size of the actual hole in the body. That actually worked pretty well. I also realized there was some kind of material behind the body, perhaps a welded nut of some kind, where the old bolt would have threaded into.

So rather than use a sheet metal bolt, I decided to tap the hole. Except I only have metric taps. So I used an M10x1.5 tap.

I couldn't fit the tap handle in there so I went redneck and built a series of adapters for my drill, like so:
S7302598.JPG
I used low speed and lubricated the tap with 3-in-1 oil. Still, that didn't seem to be going well. The 5/16" hole didn't seem like it was quite the right size for an M10, plus it wasn't perpendicular either. I switched back to the drill bit and tried to make the hole a little cleaner. It seemed like the tap was actually just drilling into the hole. But I kept at it and really put some force on it. Eventually, it actually began making threads! Nice.
S7302600.JPG
I splurged and bought a stainless bolt and washer, which cost $3.10. I threaded it in and made it snug but not ridiculous and bam, filler secured, only 3 years after I initially broke the original bolt off.
S7302601.JPG
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