MHKflyer52 Posted June 30, 2009 Share Posted June 30, 2009 Ok I am stumped on this one. :banghead: The right front tire of my 7 keeps going flat well looses its air (normal air pressure 18psi cold) only after sitting a couple of days. I have had the tire inspected for a puncture twice now (taken off the rim and checked) and have found none, replaced the valve stem both times, placed the wheel and tire in a water tank to see if we could see any leaks from the rim, tire and valve stem but did not see any. Any sugestions as what could be the problem. Link to comment Share on other sites More sharing options...
thegoat Posted June 30, 2009 Share Posted June 30, 2009 This is most likely not at all related to your post, but is similar. On my daily driver, my left front wheel seems to lose pressure quicker than the others. It does not go fully flat, but is off by a few pounds usually. Rotating the tires does not change this. I wonder if it is the wheel that hits my driveway (one of those half curb subdivision types) and other ramps at the highest speed that causes it - like it forces the air out. Link to comment Share on other sites More sharing options...
slomove Posted June 30, 2009 Share Posted June 30, 2009 That is stumping indeed. I would suspect a cracked rim but if you have dunked to whole thing into a tub and don't see bubbles while losing pressure....I would call the Vatican for a certified miracle. Gert Link to comment Share on other sites More sharing options...
Spaz Posted June 30, 2009 Share Posted June 30, 2009 Two ideas: 1. The rim is not clean and making a good seal. When the tire is off did you clean it really well? 2. A very small crack in the rim. Link to comment Share on other sites More sharing options...
Al N. Posted June 30, 2009 Share Posted June 30, 2009 Here is what I suspect...cut in the tire (or crack in rim) that only manifests itself when the tire is loaded with the weight of the car. Hence, you would not get the leak to replicate by just putting the tire/rim in water. I once had a tire that seemed to hold air when off the vehicle, but not on the vehicle, and this ended up being the case. The shape/nature of cut was that it "healed" enough upon inflation to appear to hold air, but it wouldn't continue to hold it in actual use. Link to comment Share on other sites More sharing options...
Davemk1 Posted June 30, 2009 Share Posted June 30, 2009 Here is what I suspect...cut in the tire (or crack in rim) that only manifests itself when the tire is loaded with the weight of the car. Hence, you would not get the leak to replicate by just putting the tire/rim in water. I once had a tire that seemed to hold air when off the vehicle, but not on the vehicle, and this ended up being the case. The shape/nature of cut was that it "healed" enough upon inflation to appear to hold air, but it wouldn't continue to hold it in actual use. I suspect you nailed it. The same thing happens with bicycle tires. A small cut that closes itself and doesn't leak or does so very slowly but when the cut is rolled over it leaks a bit more and with every rotation it leaks. dave Link to comment Share on other sites More sharing options...
slngsht Posted June 30, 2009 Share Posted June 30, 2009 Al, very clever. Link to comment Share on other sites More sharing options...
athens7 Posted June 30, 2009 Share Posted June 30, 2009 I had a similar problem with one of my wheels/tires (I have the 16" 5 spoke Caterham wagon wheels). There was a small flaw in the casting of the wheel such that it was porous; we finally noticed a very small stream of bubbles from the wheel itself, rather than the tire. Jeff Sloan at British Auto was kind enough to swap it out for me. Link to comment Share on other sites More sharing options...
Al N. Posted June 30, 2009 Share Posted June 30, 2009 I suspect you nailed it. The same thing happens with bicycle tires. dave Notice that I didn't say what vehicle! I'm pretty sure it was with a mountain bike tire that I had this experience! Link to comment Share on other sites More sharing options...
Silk Posted June 30, 2009 Share Posted June 30, 2009 I agree with Brad. Cast wheels can have pin hole leaks in them. Many people coat the inner surface of the wheel with a sealer before mounting the tire. Not all that uncommon. I had one new set of wheels two of which leaked badly. Sealed them, and no problems since. Link to comment Share on other sites More sharing options...
TLRracer Posted June 30, 2009 Share Posted June 30, 2009 I'm thinking you have a flat tire... and if there was oil under the car I am pretty sure you have an oil leak too. Time to buy a new tire. Link to comment Share on other sites More sharing options...
WestTexasS2K Posted June 30, 2009 Share Posted June 30, 2009 I agree most likely rim leaking. Try over inflating the tire to the max PSI and see if it bubbles. You can also get them to apply bead wax to the bead just to make sure it isnt coming from there. Small cuts will show up if the tire is over inflated from its normal pressure. Link to comment Share on other sites More sharing options...
Ian7 Posted June 30, 2009 Share Posted June 30, 2009 Its not uncommon for tires to bleed air through porosity in the sidewalls that wont show in a dunk tank; more common on lightweight race tires, but may be the case here.... Link to comment Share on other sites More sharing options...
Silk Posted July 1, 2009 Share Posted July 1, 2009 Ian, If it were me, and assuming you don't have tire pressure monitors, I'd hit the offending tire with a little tire sealant. That should take care of porous rims or side walls, bead leaks, etc. Not much $$$ and no downside. Gary Link to comment Share on other sites More sharing options...
TheDingo8MyBaby Posted July 1, 2009 Share Posted July 1, 2009 Ian, If it were me, and assuming you don't have tire pressure monitors, I'd hit the offending tire with a little tire sealant. That should take care of porous rims or side walls, bead leaks, etc. Not much $$$ and no downside. Gary I'd argue that there is a few downsides... 1. It's messy and some tire shops will charge you if they have to deal with it. Or may refuse or not be able to fix your tire if you put it in. 2. It ads weight and unsprung weight at that. 3. If it doesn't coat evenly you can develop a pretty bad vibration-which is probably compounded by you driving a 7. Link to comment Share on other sites More sharing options...
MHKflyer52 Posted July 1, 2009 Author Share Posted July 1, 2009 Ok Thanks for all the good feed back on my tire situation. I am going to try the inflation to max pressure and check for leaks one more time before breaking the tire down again as it is still loosing air when sitting in the garage. I am concerned that I could have a small crack in the bead of wheel / rim that we have not spotted as I have looked at the outer bead area and their seems to be a curb blemish on the rim that I had not noticed before. Maybe it is time for some new wheels and tires for my toy............just have to sell the wife that the rims are not safe which should not be to hard to accomplish. Again thanks for all the input as I sure have been shaking my head over this problem. I will let you know what I find out after checking the wheel / rim and tire later today. Link to comment Share on other sites More sharing options...
Croc Posted July 1, 2009 Share Posted July 1, 2009 ......just have to sell the wife Will she bring enough to pay for the rims? Link to comment Share on other sites More sharing options...
MHKflyer52 Posted July 1, 2009 Author Share Posted July 1, 2009 (edited) I would have to say she is priceless to me so I don't think I will find out......:rofl:.....besides is that not illegal......:rofl: Edited July 1, 2009 by MHKflyer52 Add more to post. Link to comment Share on other sites More sharing options...
Dave W Posted July 2, 2009 Share Posted July 2, 2009 Martin I had the same problem with one tire, I finally put about 100 psi into the tire and found the smallest of air leaks at the tire to rim bead area. I did not want to use a tire sealer because of the problems mentioned. I broke down the one side of the tire, cleaned the rim and spray a little Hi-Tac gasket around the rim bead surface. A year later and it still holds air. Dave W Link to comment Share on other sites More sharing options...
MHKflyer52 Posted July 2, 2009 Author Share Posted July 2, 2009 Well yesterday late afternoon I took the tire that was leaking to my friend’s shop where we removed it from the rim and die penetrated the rim to see if there are any cracks. Well we did not find any but the rim has many very very small pin holes in the main part of the wheel between the rim beads. I now can see how the air was escaping when sitting for an extended period of time as the rim seems to be porous from what the die penetrate shows. My friend said that he has seen this occur on aluminum cast rims when they have been refurbished and refinished without the inside surfaces being sealed as my rim has been by me. So the simple fix seems to be to coat the inside surface of the rim with a rim sealer to plug any microscopic pin holes that might be the offending leak and then reinstall the tire and inflate and then let it sit to see if it leaks down. He also suggested that I clear coat the outside surfaces of the rims that I have as I have never done that and that will help fill any of those very very small pin holes that one does not see without die penetrate. Well it looks like I have solved the leaking tire problem for the time being but now I am also wondering if the other three rims will need the same treatment in the feature so I am now on the hunt for some new rims that will be lighter than what I have now as these rims are heavy compared to the newer rims that are in my friends shop. Just have to find the correct offset and lug pattern as the rims that he has in stock are for the more modern autos which all seem to be front wheel drive and have very large offsets compared to what mine are (3.75” from the inner bead to the lug face) so now I get to start looking for a wheel design that I like with the correct offset for my car. Again thanks for all the suggestions on what could be wrong with the tire and rim as I sure was at a loss. Link to comment Share on other sites More sharing options...
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