Rear view mirror and mounting devices

I have a 2013 TDI SEL. My RVM is the auto-dimming one and has the rain sensor. Yesterday, my mirror fell off, and that's literally the first time that's ever happened to me, in 27 years of driving. The adhesive is where it failed - the bracket that mounts the rain sensor to the rest of the assembly is still tight.

So, I was wondering if it might have been because of the two devices I had mounted on it - a radar detector and a dashcam. I like mounting them there because I don't have to worry about removing them when I put up my sunshade.

The two items together are just under 14 oz. The radar detector is 8 oz. because the mount is a bit bigger.

It doesn't seem like the kind of thing that would be heavy enough to dislodge the adhesive, but it's the only thing that has changed. It's also possible that I accidentally knocked it loose while putting on one of the mounts, since it's kind of tight up there.

Another data point is that my windshield had been replaced, by Safelite. They're going to replace the windshield under warranty since that's the only way they can re-mount it. That's fine by me, because the current windshield somehow got some gnarly scratches on it.

Anybody else have multiple devices mounted to the RVM like I did, or have problems with the adhesive giving way?

That's nearly a pound of weight, very possible that the extra weight was the root cause.

Could also be the previous glass replacement didn't have a perfect job of gluing the mirror.

But I think I'd find another spot for the extra gear.

Yours
Vern

If the windshield has been replaced once already, then I would bet that the mirror wasn't mounted as securely as the factory would have done.

jck66 said:

If the windshield has been replaced once already, then I would bet that the mirror wasn't mounted as securely as the factory would have done.

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I'm going to take a look at the glass when the guy comes on Thursday. Both places I called seemed to indicate that the rain sensor bracket comes attached to the glass, or maybe it's attached at the time of installation; either way, they wouldn't just re-attach the existing one.

If it's not attached when it arrives, I'm going to ask him to really make sure it's on there well. It didn't look like a heck of a lot of adhesive was used for the initial attachment.

Depends on the adhesive to a degree, but all things being equal a thinner bond line (i.e. less adhesive) will be stronger than a thicker one. Particularly important for rigid adhesives.

Yours
Vern

Did Safelite install the correct glass? The glass should have this permanently bonded plastic ring for the mirror to mount to.



They could have installed replacement glass that didn't have the mounting ring and glued the mirror on. If so there is not much surface area and the mirror would fall off in short order.

As an aside I had to have my glass replaced a few months ago. My research swayed me against Safelite.

http://forums.tdiclub.com/showthread.php?t=451824

Good luck.

BKmetz said:

Did Safelite install the correct glass? The glass should have this permanently bonded plastic ring for the mirror to mount to.

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That's what I'm going to make sure of when they come. I didn't know that was a thing when they did the replacement, but now I know what to look for.

They could have installed replacement glass that didn't have the mounting ring and glued the mirror on. If so there is not much surface area and the mirror would fall off in short order.

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My guess, though, is that they did put the right glass on since it stayed attached for about two years. I figure I must have either knocked it loose or the sheer weight of the devices did it. Hopefully the former.

2 years is way too long for the mirror to stay attached to the glass without the mounting ring. I'd say the failure was either poor replacement technique or poor quality materials.

They did install the right glass. It was a brand I'd never heard of; I was hoping for Saint-Gobain or at least Pilkington, but who knows, maybe it will be great.

On another note, I think I might have figured out what happened. When I was adjusting the mirror, it struck me that adjusting it was a lot harder when the mounts were in place; the radar detector mount ends up right in the space between the mirror and the plastic cover that goes over the arm. I wonder if that put additional strain on the bracket when I adjusted the mirror, which eventually led it to fail.

That's quite possible. The bond would be most vulnerable to peel, and over time you may of started a crack at the edge of the bond line.

Yours
Vern

Mr. Furious said:

They did install the right glass. It was a brand I'd never heard of; I was hoping for Saint-Gobain or at least Pilkington, but who knows, maybe it will be great.

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There should be some kind of logo and specs printed on the glass in a corner. You're not going to get St Gobain or Pilkington unless you specifically ask for it, and if the installer is willing to order it.

Safelite bought Guardian a few years back. Gaurdian is the OEM supplier to VW for the NMS Passats. The VW Gaurdian OEM glass is made in MI.


Now it gets complicated.

The VW Guardian OEM glass is made in the US. The Safelite replacement Guardian glass is made in China. I'm sure the Guardian replacement glass is at least 1/2 the cost of ordering and using VW OEM glass. And to complicate things even more, the Safelite installer could have used something else besides Guardian replacement glass to give himself more profit.

Cheap replacement glass is all insurance driven to lower replacement costs.

I wish VW didn't use such a soft glass. The last 6+ cars I've purchased start getting fine scratches within 10,000 miles where the blades reverse direction. I don't see that in other brands. Since my cars were built in multiple locations (Tennessee, Mexico, places in Europe), it's not likely just one manufacturer. VW must spec the glass that way.

atc98002 said:

I wish VW didn't use such a soft glass. The last 6+ cars I've purchased start getting fine scratches within 10,000 miles where the blades reverse direction. I don't see that in other brands. Since my cars were built in multiple locations (Tennessee, Mexico, places in Europe), it's not likely just one manufacturer. VW must spec the glass that way.

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The Pilkington glass that came with the car didn't have that problem, but the Saint-Gobain glass was TERRIBLE in that regard. Absolutely the worst glass for scratches and dots that I've seen in my life, by a longshot.

Also, the glass was something called "Fuyao." I assume that's Chinese for "cheap crap," though they probably have many words for that.