Baffling rim leak
02-09-2018, 05:52 AM
#12
AudiWorld Super User
Last time I had something similar, was an old puncture. The guy who did the repair had over rubbed (with the rotary tool) the internal rubber near the puncture, with the result of every 7 days to need additional couple of decimal (of bars) pressure, but it was not noticeable when they were searching for leaks. The foam polyurethane did not work so eventually I replaced all 4 tyres.
My wife had problem with 2 stem valves not properly tightened.
p.s. I never heard that aluminium rims can leak, unless there is a crack or a manufacturing irregularity / defective. I would get a second inspection done at a different place. In case the rim has cracked I would replace it.
My wife had problem with 2 stem valves not properly tightened.
p.s. I never heard that aluminium rims can leak, unless there is a crack or a manufacturing irregularity / defective. I would get a second inspection done at a different place. In case the rim has cracked I would replace it.
The most common souce of leaks is corrosion of the wheel tire bead sealing area. This gets worse when the wheel protective coating/paint is scraped off by the tire mounting equipment, exposing bare aluminum alloy.
02-09-2018, 05:57 AM
#13
My old 4runner had the same problem, one tire keeps losing air slowly in the a week or so. No nails or puncture. Rims had corrosion. Thought I had to buy new rims. Tread was still thick. Turns out it was tire rot. They were just old, over 5 years old by looking at the date. It was developing micro cracks. Changed all new tires and all was good.
02-09-2018, 09:14 AM
#16
AudiWorld Super User
I also suggest that if anyone has a leaking tire/rim and removes the tire/rim and places it in water to find the leak, it may show up. I have a large shallow container that will accept the tire while the tire is on the vehicle. Jack up the tire, place the water
filled container below it, and lower the tire into the container where the full weight of the vehicle distorts the tire sidewall, will now indicate leaks that it didn't before weight loading.
02-09-2018, 01:34 PM
#17
AudiWorld Super User
Thread Starter
Jason-
Racing often has to have different priorities. Could be "rubber" is just specified by an old rule. Could be it seals better, or is quicker to mount and replace. Metal would probably use an o-ring so it comes back to rubber parts anyway. And if you hit a rubber valve stem, it deflects where metal would snap off. So...someone in the racing department of Goodyear or Firestone or whoever can probably give you a better idea, but I'm betting it isn't just "because we like black stems". (G)
Dennis-
Green goo (or other brands and colors) probably would not "spin up" to the level of the rims, unless it was either very generously applied, which is a problem, or very thin, which is another problem. The goo has to be "flowed" into the leak to seal it, so a very slow leak would be doubly hard to reach.
Bob-
I'm actually familiar with porous castings. Many years ago "we" had a customer with a new GM product who swore his coolant was leaking out. And it was. The shop just couldn't find anything that was leaking. Hoses, cap, water pump, head gasket....everything was FINE. But in the morning, sire enough, there was a big green puddle under the car. It turned out the ENGINE BLOCK was porous, a bad casting.
So aluminum wheels...sure, why not. Proper drop forged or billet alloy wheels...less likely. Incredibly less likely to only become porous four years down the line.
BUT THE GOOD NEWS IS!
I took my favorite Slime automatic air pump down to the car today. Hook it up, the PSI is stored, it inflates all four to the same pressure, cuts off, and makes life easy. So the pump is telling me "42" which I know is the secret of the universe but I can't figure out why the pump got reset to 42 and won't clear. Duh, no, the ace wheel man who reseated a tire yesterday? Put 42psi in that tire. 36.5 psi in two others, and only 34.5 in the fourth tire.
So my TPMS system was quite correct to tell me that fourth tire was badly underinflated....compared to the rest. You can't just make this stuff up, can you?!
I took 'em all down to 32 stone cold, and will keep an eye on them. It is somehow not reassuring to know that greasemonkeys are still alive and well, although I'm quite happy that he didn't damage anything, like the rim.
If I just drive into the shallow end of the pool, I can submerge all four tires without needing to jack up the car, right? Or do I have to open a door first, to make sure it doesn't float? (sigh)
Racing often has to have different priorities. Could be "rubber" is just specified by an old rule. Could be it seals better, or is quicker to mount and replace. Metal would probably use an o-ring so it comes back to rubber parts anyway. And if you hit a rubber valve stem, it deflects where metal would snap off. So...someone in the racing department of Goodyear or Firestone or whoever can probably give you a better idea, but I'm betting it isn't just "because we like black stems". (G)
Dennis-
Green goo (or other brands and colors) probably would not "spin up" to the level of the rims, unless it was either very generously applied, which is a problem, or very thin, which is another problem. The goo has to be "flowed" into the leak to seal it, so a very slow leak would be doubly hard to reach.
Bob-
I'm actually familiar with porous castings. Many years ago "we" had a customer with a new GM product who swore his coolant was leaking out. And it was. The shop just couldn't find anything that was leaking. Hoses, cap, water pump, head gasket....everything was FINE. But in the morning, sire enough, there was a big green puddle under the car. It turned out the ENGINE BLOCK was porous, a bad casting.
So aluminum wheels...sure, why not. Proper drop forged or billet alloy wheels...less likely. Incredibly less likely to only become porous four years down the line.
BUT THE GOOD NEWS IS!
I took my favorite Slime automatic air pump down to the car today. Hook it up, the PSI is stored, it inflates all four to the same pressure, cuts off, and makes life easy. So the pump is telling me "42" which I know is the secret of the universe but I can't figure out why the pump got reset to 42 and won't clear. Duh, no, the ace wheel man who reseated a tire yesterday? Put 42psi in that tire. 36.5 psi in two others, and only 34.5 in the fourth tire.
So my TPMS system was quite correct to tell me that fourth tire was badly underinflated....compared to the rest. You can't just make this stuff up, can you?!
I took 'em all down to 32 stone cold, and will keep an eye on them. It is somehow not reassuring to know that greasemonkeys are still alive and well, although I'm quite happy that he didn't damage anything, like the rim.
If I just drive into the shallow end of the pool, I can submerge all four tires without needing to jack up the car, right? Or do I have to open a door first, to make sure it doesn't float? (sigh)
02-09-2018, 02:31 PM
#19
AudiWorld Super User
Thread Starter
You're right Murray. The Slime autoinflator is only accurate to 1/2 psi, in theory. But I suspect it is consistent, so even if it is 1/2 psi off, or one psi off, at least all four are PROBABLY within 1/2 psi of each other, and that's better than I would do by eye with an old pencil gauge. (Which I still prefer, but if you ask four of those for a reading, they'll give you six different answers. Whatever happened to quality control?!)
02-11-2018, 09:34 PM
#20
AudiWorld Super User
I had a slow leak and it turned out there was a small factory sticker that was placed right where the tire bead sits on the rim. I'm not sure why it took >15K miles for the leak to start but I was happy that the fix was easy and the tire shop didn't even charge me for it.