phantom flat - PeachParts Mercedes-Benz Forum

jsmith · #1 03-17-2003, 08:58 PM

i just put on my dunlop sp5's after today's warm weather and everything was great except tonight when i went out i noticed the car was pulling to the left. sure enough pressure was 10 lbs low on the left front and i quickly put my spare on. i inspected the tire and could not find anything so i reinflated it to proper pressure. i will take it to the tire shop first thing tomorrow. this is the second time it's happened in about 12k miles. the first time it was the same thing but on the opposite tire - just lost 10 lbs. that time i brought it in to the local tire shop where they found nothing wrong. no further incidents until i stored the tires for the winter. when i checked today before mounting, they were all at the proper pressure. i suspect that tomorrow i will discover that there's no puncture either.

anyone have any ideas on what could have happened? the wheels are mille miglia bellos. i have been very happy with the wheel / tire set thus far...

Robert W. Roe · #2 03-18-2003, 07:05 AM

I've had this happen to me a couple times too. I never ascertained a real reason, but I surmise that someone maybe let air out of my tire. A slow leak is one thing, dropping pressure and not finding a leak, that's weird.
Hope this helps,

jsmith · #3 03-18-2003, 07:24 AM

yeah, the first time it happened there were opportunities for some malicious mischief. in this case i left it for maybe an hour in the dentist's office but it drove fine on the way home. over the past year and a half i have driven over roads both good and bad and these are the only instances when this has happened. the last time, the tire guy just shrugged his shoulders and sent me off with no charge for checking. i wish i had an answer...

Luke@tirerack · #4 03-18-2003, 09:22 AM

check the valve stem core ... common problem

jsmith · #5 03-18-2003, 09:28 AM

luke,

should i just replace the core regardless? it is clean since i make sure it's always capped. i checked it with a handy bubbly liquid

and it wasn't leaking...

Luke@tirerack · #6 03-18-2003, 09:51 AM

my grand daddy used to say

"if it ain't broke don't fix it"

placo1 · #7 03-18-2003, 10:41 AM

Are the wheels chromed? I've heard as chrome plating ages it will flake where the tire is mounted and allow air to leak out. Just a possibility.

jsmith · #8 03-19-2003, 07:07 AM

wheels aren't chromed and the tire shop found nothing just as i expected and it held pressure overnight so i chalk it up to springtime gremlins...

Robert W. Roe · #9 03-19-2003, 11:45 PM

I remember hearing something about dirt/sand/small stones inside the valve stem caps making a tire go flat. Not sure how this ould happen accidentally though.

jsmith · #10 03-20-2003, 06:24 AM

i know about that dirty trick - the grit is placed in the cap so that when you screw it on it pushes the core down and releases air slowly...