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16th January 2022, 07:46 | #11 | |
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Thanks Chris but when the valve was submerged in the paddling pool there was no sign of air escaping from the valve. There again there's no sign of air escaping from anywhere, but escaping it is so I suppose that form of thinking is unreliable.
Quote:
The owner is considering Cliff's diagnostic procedure of swapping tyres. Simon
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16th January 2022, 11:09 | #12 |
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Generally with gradual air loss if there’s no puncture it can only be a few things. The valve, is the core tight? You say there were no bubbles when submerged, did you apply movement to the valve whilst submerged or is it an early tpms metal type? It could be removed and a standard valve added for testing. Although the tpms light would be on in the process.
Alloy wheels can become porous but generally only old ones, back in the day an inner tube would be fitted to prove or disprove but not possible now. Bead sealing, I’m guessing when bead sealer was used the wheel was thoroughly cleaned? Age of the tyre, the tyre itself can become porous which Is difficult to prove but if it’s dated as an old tyre I’d probably start here as If it doesn’t fix it at least the tyres are safer
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16th January 2022, 11:29 | #13 |
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The best way with these slow leaks is to wash the tyre off with clean water then submerge the wheel completely including the valve in clean water, no soap, you will have to weigh it down.
Then observe over it over a day or so checking it as often as you can and you will see where the leak is. Depending on the size of the hole, or holes, you may not see a stream of bubbles, with a very small hole what you will see is an air bubble forming on the tyre, or wheel at the site of the hole, once it reaches a certain size it detaches and floats to the surface. Turn it over and do the same on the other side, it can obviously be time consuming but this is the only certain way of finding very small leaks, soapy water rarely shows these up. I had a similar thing with a tubeless ride on mower wheel, losing a small amount of pressure taking around 14 days + to get really flat, normal pressure 30psi did the soapy water thing, nothing, did the quick putting it in water, nothing, increased pressure to 60psi nothing, then did the one as describes above, I put it where I would be constantly walking past and started seeing the occasional bubble surface from three areas. It took a good magnifying glass and a good light to spot the culprits which were the tiny tips of thorns, still stuck in the holes, obviously only the minute sharp tip, literally a pin NAUGHTY WORD-NAUGHTY WORD-NAUGHTY WORD-NAUGHTY WORD-NAUGHTY WORD-, must have penetrated the inner tyre skin. I removed them, thought a good dose of the old Slime would work, nope, Slime works by the fibres in the solution filling the hole, but in this case, with the hole being so small, the fibres were too large to enter and seal the hole. One thing doing this did though, was show up another hole I had missed, it did this because the blue Slime fluid passes through the hole and can be seen on the surface. I stuck a spare wheel on meaning to ream out and plug the holes with a repair kit but haven't got round to it, if I get the chance in the next couple of days I'll dig it our and take a couple of photos.
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16th January 2022, 12:12 | #14 |
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I have same problem on a Focus alloy wheel. Sometimes pressure holds at 31psi for days, even weeks, then it drops by several psi in a day or two. I know it is leaking at the bead because I observed bubbles when I put the wheel in deep water in the bath with no soap. I cleaned the alloy rim, painted it then applied sealer but it still leaks. I wonder if the intermittent nature of the leak is down to where the wheel stops when it is parked.
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16th January 2022, 12:25 | #15 |
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16th January 2022, 12:25 | #16 | ||
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Quote:
I regret that I didn't apply movement to the valve whilst submerged. The car does have a tyre pressure monitoring system (post no. 1). The alloy wheel (and the car) is 8 years old so I wouldn't expect porosity. When the bead sealer was applied the wheel rim had already been cleaned then refurbished by powder coating (post no. 1) so I think we can take it that it was as clean as clean could be. Quote:
Simon
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16th January 2022, 14:35 | #17 |
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I should have added in my post that care needs to be taken with some puncture sealants in that they can block the valve core and sometimes the valve stem, not a massive problem but one you don't want if you just want to put a bit more air in.
A quick test to see if this has happened is to push down on the core as if you were releasing air, if it is stuck, or it goes down and no air is released, even though there is obviously air in the tire you will need a new core, and possibly clean out the stem bore with a suitable tool out of your bits box. Some off road cyclist, off road motorbike/quad bike and other similar sites recommend, where possible, to have the valves at 12 o'clock when parked up/stored for a while and when inflating, deflating, if possible put the valve at 12 o'clock for a while to allow any fluid to drain out, either way at any time it's best to have the valve at 12 o'clock when inflating.
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16th January 2022, 17:19 | #18 | |
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Quote:
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18th January 2022, 14:06 | #19 | |
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TC |
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19th January 2022, 07:44 | #20 | |
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Quote:
Simon
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