I went to add some air to the tires this weekend (Low Pressure Monitor was lit).

As soon as I pressed the air chuck onto the pretty metal valve stem, the damned valve stem snapped off!


Appears to be made from some brittle white metal rather than a nice ductile machined brass like it oughta be.

Be VERY CAREFUL with these valve stems.

Heading to Nissan now with the tire.

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Edit 8/30

For those of you unwilling or unable to read through all of this thread, the cause of the breakage was determined to be the use of a common self clamping air chuck (mostly what you find at most gas stations and any you may have bought to use with your compressor other than the simplest little brass ball type. If you feel any "snapping" action when you press the air chuck on a valve, chances are its a self clamping type).

Nissan does not provide any warning about this. Be very careful with your TPMS valve stems... they are very fragile.

I found this very informative article on TPMS by a Ford tech who had just taken a course on it:

http://www.explorerforum.com/forums/...d.php?t=137498

Good info and pics of the system used by Nissan (and at least Ford and Chrysler, apparantly).

You can check out all of the article but there was an interesting list of cautions in the post:

CAUTION:

• If the metal stem cap is stuck, DO NOT use pliers to remove it -- it will break!
• DO NOT use a self clamping air chuck on the TPMS sensors, valve stems will break off! These things are VERY fragile!
• Valve cores of the TMPS are not the same as those in regular rubber stems, do not lose them.
• DO NOT replace cap with a rubber one, it will mess up the transmitters
• DO NOT use "fix-a-flat" with a TPMS; it will clog the sensor and render it broken.

Nissan warns about none of these except the fix-a-flat.

 

Wow! The valve stem has been around since the advent of tubeless tires in the late 1950s. Anyone else here remember when all tires were 'tube-type', and the stem was part of the inner tube?

One would think the valve stem would be bullet-proof by now. But then I remember looking at the first '07 to arrive at my dealer a few months ago, and noticing that the new silver valve stems sort of had a mottled 'pot metal' look. And pot metal is not very strong.

We can only hope either jcalabria is a body-builder who doesn't know his own strength, or happened to get the only faulty stem in the factory. What Nissan does NOT need at this point is to have lots of stems breaking. That could be considered a safety issue, requiring a recall of all '07 Maximas.

 

Dealer claimed it was the first thay have had to break, but I don't know if any other models/years have used that valve stem. Salesman told me thay have sold only one other '07 so far (as I have mentioned before, unless a customer specifically asks for one, they are keeping them under wraps till they reduce their '06 inventory)

They warranteed it (not that they shoudn't - I was just asking it to do its main function), and its a good thing, because the TPMS sensor and the stem are an integrated unit, can't imagine what that would have cost. This most definitely not your run of the mill brass and rubber stem (though the valve inside WAS your good old run of the mill Schrader valve).

BTW, pot metal is EXACTLY what the broken end of the stem looked like, but it was very light, like aluminum. I took enough metallurgy classes in college to know what brittle metals look like when they fail, and this looked like that. I figure it has to be some form of aluminum alloy so as not to create corrosion from dissimilar metals. There is no rubber to isolate them.

 

Sorry to hear that, I will check my stems in the morning.

Nick

 

jcalabria - The '07 is absolutely the first Maxima to have these particular stems. It is also the first Maxima to have the now-required tire pressure sensors and low tire pressure display.

Your post indicates that the newly designed stem is tied to the new pressure sensor system. Hence, should stem breakage become a problem, this would be a 'safety' issue, requiring a recall. We don't need for a tire to suddenly lose its air from a broken valve stem while passing a semi at 70mph.

 

I figured it was the first Max, but I didn't know if the Z or an Infiniti had used them. Fortunately, they had them in stock (or were readily available for a same day repair).

It appears that the whole assembly just unscrews from the outside of the wheel. There was no evidence that the tire was dismounted from wheel (thankfully... don't need any wheel balance problems). The base of the stem has a hex head... looks like you just put a deep-well socket on it and unscrew it. Maybe there is more to it, but it doesn't look like it.

 

Wow, so if someone likes your pretty little stems they can just unscrew it and leave you stranded, god knows I lost my fair share of pretty little metal caps, but the whole stem ouch.

 

tsk tsk, how can it break when its all aluminum locked down on wheel...



bravo to nissan for warrantying it.

 

all the infinitis with TPS usethe same steam. My brother M45 has them

 

ahh, mmm,, you mean 90mph right.,, ,,

 

It broke at the thin wall part of the valve stem, not the thick body.


In my mind, there is no excuse for making that part of the assembly out of aluminum. If you look at the inset you can see how little material there actually is along the break line. There is a reason these stems have been made of more ductile materials such as brass for decades.

All I did was push on the air chuck and it snapped right off. Maybe this one was defective... maybe they are all a disaster waiting to happen. Either way, there was no reason that Nissan should not have warranted it, as it was not abused in any way.

If it had broken under other circumstances, I might have had motive to tell Nissan otherwise, but I would have had absolutely no reason to mention it on the forum.

If somebody wanted to clip one, they could unscrew it. If they just wanted to strand you, I am sure that anybody could walk up to these wheels and step on the stem and snap it off with little or no effort. But that's not really any different than somebody with a pair of pliers pulling out a rubber stem. Either way you would be stranded. The difference would be in the replacement cost.

 

That pot metal is cheap crap. I’ve seen the same problem occur in the audio industry where loudspeaker manufacturers use that garbage in their binding posts (where the speaker cable attaches to the speaker). The posts often twist off with ease or crack and literally fall apart in no time (due to common micro-fractures). I’ve had this happen on a dozen speakers I’ve repaired on various installs in the past few years. The stuff should be banned!

 

Well, I was thinking more like this, if it does break easily, and you are out of warrenty and it costs an arm an a leg to replace...... I think you can get to where I am going.

 

"Clip one" is Jersey slang for the same place you were going.

 

Found this very informative article on TPMS by a Ford tech who had just taken a course on it:

http://www.explorerforum.com/forums/...d.php?t=137498

Good info and pics of the system used by Nissan (and at least Ford and Chrysler, apparantly). From the pics, its obvious that they must have dismounted my tire to replace the TPMS stem.

You can check out all of the article but there was an interesting list of cautions:
Note the warning about the self clamping air chuck.... No shït!!! Would have been nice if Nissan included the same warning somewhere!

BTW - Nissan's list price for the TPMS valve stem is $291 each!

 

well put it this way, now that from now on, every single vehicle out there is going to have this sensors i would assume prices will go down, and that you do not have to get this things from the stealership,
$291-40% nissan fee-demand disscount, i would say that by next year youll find them in autozone or pepboys for about 60 to 70 bucks. if not less,,, and by the time they ran out of warranty theyll be less that 30 bucks

 

Good info, Thanks!

FWIW, I had these on my Titan and they were even moved from the stock wheels to some aftermarket wheels with no problems.

I wonder if maybe you had a stem that was just installed too tight causing it to weaken?

 

I just went through the manual in detail and found no mention of any of these issues except the fix-a-flat one.

The manual DOES state that the spare does not include a sensor, with no differentiation between a full size and a compact. This makes some sense for the compact spare, but if I had paid for the full size spare/aluminum wheel option and coudn't use it because it didn't have the TPMS sensor, I'd be PÏSSED. It could be that the full size spare has the sensor, but its just not monitored. Anybody out there with the VDC option might want to check and let us know if their spare has the TPMS valve stem.

 

My Titan had a full size spare, and it did NOT have a sensor in it. I believe the owners manual even mentioned that fact.

 

Spare wheel match the road wheels? or just a plain steel one?

 

It was a spare wheel and tire that was exactly the same as what came on the truck. It just had a rubber valve stem instead of the TPS one.

 

That sucks - having a full size spare w/ matching wheel you can't rotate in.

 

This reminds me of my ex-g/f...once she told me her license plate sticker "just ripped in half" and was whining that it's DMV's fault. I couldn't help but think it's only a sticker, it's gonna stay in one piece until th end of time until a human intervenes...

 

I have the full size spare and will try to remember to check tomorrow. Right now it is dark and raining at my house so it will have to wait.

 

So... exactly how many people do you know that would think twice about using the same air chuck they've used for last 15 years on every car, truck, motorcycle, lawn tractor, bicycle and wheel barrow that's passed through the garage in that period?

Since you apparently did not read through all of the posts, I will save you the time and recap:
Sorry, you're not gonna make feel guilty about this one. If Nissan had placed a warning, even buried deep in the manual, maybe you'd have a point that I didn't read the instructions. There was nothing to read - absolutely no indication that any special treatment was required other than no fix-a-flat.

 

One wouldn't clamp down either on a bicycle valve stem, because that also breaks. Imho has nothing to do with TPMS, has to do with anything that is delicate. I'm not sure where you're going when you mention 15 years and guilt. What's to feel guilty about with a warranty repair? I think you're reading too much into it.

 

The implication both of you made was that I must have done something dumb or it wouldn't have broken. It would only have been dumb if I had known, or should have known, that the TPMS stem is more fragile than a normal valve stem.

Should it be expected that somebody needs to do extensive research or attend a class before they are qualified to do something as routine as putting air in a tire? The fact is, in this case, that you DO need special knowledge to do something that is normally routine and Nissan focked up and did not provide that information.

All I was trying to do was give the members that heads-up that Nissan didn't give.

The 15 years was referring to how long I had been using that particular air chuck on a variety of different tires without incident.

 

Well, I say thanks again for the heads up. The assumption is that a metal valve stem should be tough, so who would think twice about it breaking or having to do research beforehand.

Like I've said before, I had them on my Titan for the past 2 1/2 years and have never given it a second thought (especially after having the Tire Goons switch them to my new wheels with no trouble). But since it's a new thing for you Max owners, I can understand. Plus, you can bet your *** that I was more cautious last night when I filled mine up.

 

I checked my full size spare and it has a regular valve stem. I am a bit disappointed. I am going to contact Nissan about this and complain. I doubt I will get anywhere, but we'll see.

Nick

 

That really sucks!

I understand why you need the full size spare with the VDC, but why the Knissan Knuckleheads bothered to put it on an alloy wheel when you can't use it on a full time basis is beyond comprehension. If they were going to cut costs, they should have saved the money on the wheel, too.

I was very tempted to buy through the NAV option to get the VDC/full size spare option, partly justifying it on having a fifth tire to rotate in and save me the cost of tires during the lease. "Dissapointed" wouldn't have begun to cover it if I couldn't use the wheel because no TPMS.

Unfortunately, you are correct that it will most likely do no good to complain.

Joe

 

WOW! I have the same TPMS on my z and on my Frontier and had no problems yet.... The sensors on the z have been in 3 sets of wheels by now, they did get a little scuffed up over time but no breakage. I wonder if the new 2007 models have a bad batch of these. Good luck.