Rear shelf rattle -- alternate solution
08-06-2001, 03:03 PM
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Rear shelf rattle -- alternate solution
The infamous "rear shelf rattle" has been discussed here and in the FAQ (http://www.auditt.org/faq/960471131), but I found a different solution.
My shelf would make a terrible creaking noise whenever it flexed (i.e., at every bump in the road). I took the shelf apart and removed the two metal bars to no avail, so I knew it wasn't a rattle. Instead, it sounded and felt like "stiction" of plastic rubbing on plastic.
The FAQ solution (solvent-welding the two halves of the shelf together) would definitely solve a stiction problem. Unfortunately, it's an irreversible fix: if you don't get a complete cure on the first try, you don't get a second chance. Also, any mistake with the solvent can mar the outside of the shelf.
My solution: Lubricate the mating surfaces where the insides of the shelf halves contact each other. The lubricant prevents stiction and quiets the hideous noise, but you can still take the shelf apart if necessary.
I used spray-on white lithium grease, which is a relatively high-viscosity grease that won't drip or run (if used sparingly). The key word is SPARINGLY. You want thin, uniform coverage, but no blobs of grease that might melt and drip out in hot sun.
Overspray or fingerprints on the plastic can be wiped off after assembly, but don't get grease on the fabric. You may wish to remove the fabric first, and/or apply the grease with your fingertip rather than by spraying.
Important: Lubricate all possible contact areas, not just the edges. There is a row of standoffs (little plastic "feet") about an inch from the edge, so make sure you cover the areas where they meet the other half of the shelf. I also removed the two metal bars and lubricated them just to be safe.
On my shelf, the difference was dramatic. During normal driving, the shelf is dead silent. I can still hear a faint noise if I remove the shelf and flex it by hand, but I'd bet it's 20 dB quieter.
Longevity is another matter. So far, so good after three days. If the noise ever comes back, I'll find a better fix and post it here.
--Chris
My shelf would make a terrible creaking noise whenever it flexed (i.e., at every bump in the road). I took the shelf apart and removed the two metal bars to no avail, so I knew it wasn't a rattle. Instead, it sounded and felt like "stiction" of plastic rubbing on plastic.
The FAQ solution (solvent-welding the two halves of the shelf together) would definitely solve a stiction problem. Unfortunately, it's an irreversible fix: if you don't get a complete cure on the first try, you don't get a second chance. Also, any mistake with the solvent can mar the outside of the shelf.
My solution: Lubricate the mating surfaces where the insides of the shelf halves contact each other. The lubricant prevents stiction and quiets the hideous noise, but you can still take the shelf apart if necessary.
I used spray-on white lithium grease, which is a relatively high-viscosity grease that won't drip or run (if used sparingly). The key word is SPARINGLY. You want thin, uniform coverage, but no blobs of grease that might melt and drip out in hot sun.
Overspray or fingerprints on the plastic can be wiped off after assembly, but don't get grease on the fabric. You may wish to remove the fabric first, and/or apply the grease with your fingertip rather than by spraying.
Important: Lubricate all possible contact areas, not just the edges. There is a row of standoffs (little plastic "feet") about an inch from the edge, so make sure you cover the areas where they meet the other half of the shelf. I also removed the two metal bars and lubricated them just to be safe.
On my shelf, the difference was dramatic. During normal driving, the shelf is dead silent. I can still hear a faint noise if I remove the shelf and flex it by hand, but I'd bet it's 20 dB quieter.
Longevity is another matter. So far, so good after three days. If the noise ever comes back, I'll find a better fix and post it here.
--Chris
08-06-2001, 03:31 PM
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Interesting, but...
FWIW, after I removed the metal bars, the two halves of my shelf snapped together so tight that no amount of flexing could induce "stiction" noises for me...
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08-06-2001, 06:03 PM
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Huntingdon Audi . . . just started with them . . .
I've moved my business 10 minutes away, and so plan to use them for service from here on. How they been for you?
Also question #2. Shall we drive after work sometime? Hmmm maybe north up towards New Hope, maybe we'll get a good shot at the road leading there from 95.
Also question #2. Shall we drive after work sometime? Hmmm maybe north up towards New Hope, maybe we'll get a good shot at the road leading there from 95.