I was getting ready for a starting a fuel pump change in a few days and I found these upsetting cracks or tears making a hole in my spare tire well. I am confused.

It almost looks like someone over-tightened the (Full-sized) spare tire and the spare tire well tore or cracked on the left, non/battery side... (which seems like a thing that wouldn’t/shouldn’t be possible...) Has anyone seen something similar before and have any idea what might have happened? Does anyone know what the spare tire well made out of? (Aluminum/aluminium? Steel? Plastic? Fiberglass?) Any thoughts on what to do about it? There don’t seem to be any signs of rust, and the edges seem shiny (which has me possibly thinking aluminum?). Help?

U.S. 1997 XK8 convertible, VIN around 15,775 ish. The car is completely rust-free as far as I can tell.

 

I assume it's steel, as I don't think these cars have any aluminium panels. I'd say that has to be some sort of impact damage from below because I can't see any possibility of the spare causing it, but it is odd. I'd just get someone to just weld it back up, and I think that would do it. I certainly don't think there's an inherent problem with the car.

 

Known as the Trunk Floor Panel, it's steel although you could be forgiven for thinking it must be precious metal from the cost.





2552 UKP = 3372 USD.

I see a patch repair in your future.

Graham

 

Red,
That crack looks recent because there’s no corrosion.

The steel remains flat without dented deformity, so it is not from an impact.

The Trunk Floor Panel is steel and was pressed in 2-stages. First a deep drawing and then a 'bridge' profile imprint. Sometimes this can cause material ‘necking’ in certain zones but we can’t prove this without wall thickness measurement.

The tightened spare wheel will create tension stress both ends of the central 'bridge' profile design.

Due to the mass of the spare wheel, bumpy roads will cause vertical acceleration and deceleration leading to flexion in this zone –similar to vibration cycles.

The crack appears to wander.

All these observations suggest crack propagation from metal fatigue.

I suggest you drill ‘crack arrest holes’ at each end of the crack to immediately stop further creep. You can then look at patch options, but a patch is not always necessary. After drilling you should certainly treat all exposed bare metal.

 

I've an almost identical crack in my spare tire well. I had a mechanic examine the car to see if it might have been the result of a collision and he did not think that was the case. Glad to know it wasn't just my car, might be a defect. Options are to either get it welded or not drive the car during winter especially in areas where they use road salt.

 

Thank you all for the great answers. Chillyp, I’m so sorry that it happened on your car too. Feeling much less weirded out, though, knowing that it’s come up before and getting a few thoughts on it. I’ll definitely have to get it attended to when I get a chance.

 

I concur with the drill stop recommendation (drill a small hole at each end of the crack) and then patch with a bit of JB Weld.

 

get a body shop to weld it up proper,

 

Resolution: Just got my '97 XK8 back from the body shop and now the stress tear is all welded up, painted over, and undercoated over underneath. It was about $140 USD. He said to make it truly invisible would've been more like $500 but it looks pretty good I think. Thanks all for the input.

 

Well done at a very fair price....

 

If it weren't circled I'd have never noticed. You did it the right way - I would've just slathered some JB Weld on it and called it a day.