Watch out for this Annoying but Potentially Dangerous Problem!!! - Benzworld.org

Darkmann · 12-29-2004, 07:24 PM

I'd like to post this on all the forums - who knows how to do that??

A couple of weeks b4 the Holidays, I was traveling to Washington DC with my family in my wife's E430. This time, there was too much shimmy in the steering wheel - the car just didn't feel right. I asked her if she'd hit anything lately - No!! I knew the tire/wheel were balanced and I recall checking the pressure a few days back. I was really puszzled. At the next gas station, I stopped (the car really felt uncomfortable and 85mph is the norm) and checked the tire pressure, made sure everything was OK. Several miles later, the car would just wobble all over(like when extra low profile tires track road grooves) really badly. It felt to me like it was coming from the front passenger side tire. I pulled over, inspected the tire and couldn't find anything wrong. I continued my trip and every so often it would misbehave. I was really puzzled and so I drove at the speed limit or below for fear of the worst, afterall my entire life was in the car with me - I consider myself quite knowledgeable about tires and rims and how they should behave under load.

Anyway, we got to DC OK, parked the car and the next morning, I noticed that the passenger side front tire was flat. Forget about roadside; this was my investigation to resolve!!! Luckily for me I had a full size spare to replace the bad tire. I couldn't find any nails/tears/punctures/damage/anything wrong with the bad tire!!! Now my curiosity peaked!!!

My investigation really began the next morning when I got home. I reinflated the tire but couldn't detect any leaks. So I started playing with the tire rim/wheel lip seal, no problems there, the valve - no leaks. Then I played with the nice looking valve cap I'd purchased from PepBoys - I had the MB logoed set on several weekk earlier but some nice person kept on unscrewing them and not leaving me a note (I lost two sets of valves to this nice person!!!!), so I replaced them with these ugly pink ones!!! As I wiggled the valve cap, I could hear air sipping out. I played with the cap some more and finally decided I'd found the problem!!! When I looked inside the cap, I noticed that the rubber gasket in it was broken - it's supposed to be a nice flat thin "disk" shape. Since it was broken, a piece of it would contact the valve pin as I screwed the cap on, and the tighter I had the cap on the more it would press on the valve pin and the more air would come out of the tire!!!! To test this theory, I replaced the valve cap with those on my ML - the ones with the MB logo. I made sure to inspect the gasket!!! I remounted the tire and went to bed. The next morning, the tire was intact. I had to go back to DC later that day, so I took the E-Klass on the same highway, and I made sure to drive over the same bumps and, voila, not a problem to this day. An annoying but extremely dangerous problem I thought you should all be aware of!!! Check the insides of those vale caps!!!!!!!

**ttaleric** · 12-29-2004, 07:36 PM

Had the same thing happen to me on my C220. I bouht the Assurence tires, brand new. Drove up to college and come to find the next day i had a flat. So i took it to a gas station and filled it back up, inspected it. And didnt see anything wrong with it. I took to to the local tire shop, and they fixed it for free. Damn, NTB (National Tire and Battery)trying to kill me again!!!

Darkmann · 12-29-2004, 07:44 PM

pize98 · 12-29-2004, 08:56 PM

Funny this just happened to me the other day the tire was flat and when I took it to the station they couldnt find anything wrong. I thought it had to do with the cold weather or something.

S4toML · 12-30-2004, 07:02 AM

j/k [:D][:D]

Great post! I will have to check mine when I get home.

kenyee · 12-30-2004, 08:37 AM

you need a special key to take the caps off and you can get a logo on it. Bloody expensive at around $16 though...I figure I'd have to go through 4-5 packs of the generic chrome ones before it'd be worth it, assuming I don't lose the key :-P
The boring black rubber ones are stolen the least, from my experience...

Darkmann · 12-30-2004, 04:16 PM

Quote:

kenyee - 12/30/2004 10:37 AM

you need a special key to take the caps off and you can get a logo on it. Bloody expensive at around $16 though...I figure I'd have to go through 4-5 packs of the generic chrome ones before it'd be worth it, assuming I don't lose the key :-P
The boring black rubber ones are stolen the least, from my experience...

Unfortunately, MB has prohibited them from putting the MB logo on those valve caps - I think BMW and another big auto maker also. I have no idea why they'd do this. Anyway, that's why I don't have them.