Originally Posted by Psneeld
Here's the question...
Anyone ever have a Schrader valve in a flex extension partially fail in the release mode? It seems to take and hold air just fine, but will only release air with some tools used to fill with bleed valves on the filling device.
My main issue is that 5 out of my 6 tires work normally with my TPMS sensors that screw on the valve stems. But one tire stem is problematic and it is not the sensor (switched tires).
Pressing in the Schrader valve doesn't work unless it is one of my pressure gauges and I release through the dump button.
Is this a simple Scrader valve removal and replacement? Is there any especially good ones out there? I hate to pay a tire shop for such a simple project but I have no experience with the extensions or tires in this range 245/75 19.5 at 90psi.
Originally Posted by Psneeld
Anyone have the answer to my question(s) in the OP?
"Is this a simple Scrader valve removal and replacement? Is there any especially good ones out there? "
Originally Posted by Psneeld
I am still looking for the answer to is whether I need to look for a specific size as most ads I look up don't really describe the size differences in valve cores. Maybe it is hard to answer, and that's OK, just keep pointing me in the right direction and I am pretty good at research.
My answer to your original and initial question is no, I never "had a Schrader valve in a flex extension partially fail in the release mode
My answer to your second question is also no. It isn't "a simple Schrader valve removal and replacement
" The reason why it isn't simple is because you have not identified the type of braided stainless steel valve stem extension that you have, and the type of extension you have is a determining factor for whether or not you even have a "Schrader valve" (hereinafter valve core
) at the end that you are trying to attach a stem mountable TPMS sensor cap to.
In general, there are two types of braided stainless steel valve stem extensions.
One type remains pressurized at the same pressure as the tire and wheel assembly that it is attached to.
The other type remains UNpressurized, and only serves as a conduit through which pressure can pass when the rod inside of the extension is actuated mechanically by a physical force on the operator end, such as the pin plunger of a pressure gauge or inflator that normally depresses the valve opening pin of a valve core.
The latter type of extension is generally safer, as one can run over a road hazard such as a piece of 2" angle iron that is skinny enough to find its way in between the dual rear wheels, flung at road speed velocity, slicing or severing the braided valve stem extension. If the extension is not pressurized with the tire it serves, then any damage to the extension has no effect on the tire it serves.
On the other hand, with the former type of extension, that remains pressurized with the tire it serves by keeping the valve core on the wheel valve stem open for as long as the extension is attached, any damage to the extension that compromises the integrity of the extension, by extension compromises the pressure of the tire. Sudden air loss, rapid overloading of the outside tire in the dually pair, resulting in a single or dual blowout, along with the attendant damage to the underside of the motorhome that usually occurs.
That is the kind of experience that Scottkd shared, that you didn't ask for or about, but that cost him $16K to learn, and costs us nothing to learn from. Despite the direct to wheel mounted long valve stem from Dually Valves being solid metal, it was also constantly pressurized in the extension tube itself, so any road hazard damage to that metal tube would result in a loss of pressure to the tire it serves.
Your situation isn't that simple, because you want to permanently mount a TPMS monitor on the end of an extension that traverses the gap between the dual pair of wheels. Regardless of what type of stainless braided extension you have, the mounting of the TPMS to that extension will cause the extension to be in common pressure communication with the tire it serves.
Even if you have what the Wheel Masters brand markets as so called "Live Stem" extenders that normally would not be pressurized unless or until pressure checked with a guage or pressure adjusted with an inflator, the valve stem cap style TPMS doohicky add-on acts on the "live stem", which acts on the valve core in the valve stem directly attached to the wheel, thus making the extension the same pressure as the tire, which enables the TPMS to monitor the tire's pressure. This causes the extension to be more of a liability, due to its vulnerability to road hazards.
The tip of a live stem (or rod actuated and released) type of braided stainless steel valve stem extender might NOT be a valve core (or Schrader valve). It could simply be a stiff cable.
However, the type of braided stainless steel valve stem extension that is designed and intended to be pressurized all the time may have a valve core at the operator end, and have a fixed pin at the wheel mounted valve stem end to permanently hold open the valve core at the wheels valve stem.
So the answer to your question depends on what you have.
Yet the answer does NOT depend on any "specific size" of valve core. For automotive and truck purposes, all valve core sizes are the same. Valve cores change sizes for off road earth moving equipment (bigger) and racing bicycles (smaller), but for a 19.5" tire and wheel assembly such as what is on a 2022 Entegra Vision 29S, a standard automotive and light truck size valve core rated to 200 psi will be one common size.
Aircraft rated valve cores have higher quality elastomeric in the sealing rings, which you might favor as a pilot, and they are the same size too.
Yet since it isn't clear that the operator ends of your particular extensions have valve cores, or just guided actuating rods, it cannot be said that replacing a valve core whose presence isn't established will address the issue you are having.