TST TPMS

[navybanker]

Just replaced rubber valve stems (recommended and purchased from Tredit Tire and Wheel) with all metal on GY 614's and three out of four TST TPMS monitors leak. TST said you can tighten too much and ruin the monitors. I know you can use plumber's or pipe thread tape but about as concerned about slow leaks caused by monitors as about other tire problems. Do these tires have too much pressure at 100 PSI for these monitors? Anyone having similar problems?

[NCFischers]

What color are the rubber seals in the monitors? If they are a milky white color, call TST and tell them that the monitors leak. They sent me new ones with black seals and the leaks stopped. The monitors will handle the tire pressure.

[bncinwv]

Guess I need to check the color of the seals in the TST TPMS monitors now. Haven't installed yet so now is the time to find out. Thanks for the heads up Jim, and thanks for the original question as well. The forum comes through again it seems.
Bingo

[bw2]

A friend of mine w/ an SOB had the same problem with Pressure Pro sensors. He had the tire store remove the metal stems and re-install the rubber stems. All was good then. I really do not understand the difference, harder metal between the steel stem vs rubber stem?

[stiles watson]

Haven't had a problem on the G614's or the truck tires with my pressure Pro monitors.

[Art-n-Marge]

That makes no sense rubber or metal. The screw on part is made of metal which is then encapsulated with rubber or metal. This is a weird one.

I do know that leaky monitor does NO good. The monitor has to keep the tire valve open to read the psi and if it leaks itself, that ain't good.

One of these days when I finally get one of these tpm systems, I'll have to remember to do a leak test periodically (soapy solution on the stem/monitor and look for bubbles).

[drsmart]

We’ve been using the TST monitors with steel valve stems and Teflon tape for 3 years now. My understanding is that the weight of the sensor and road vibration can cause the rubber stem to flex rapidly and continuously enough to eventually develop into a leak or total failure. Where are most rubber valve stems manufactured? Maybe in the plant next to the Goodyear Marathon production?
Regarding the Teflon tape, I found that the sensor can vibrate loose on the stem and develop a slow leak. With a little patience applying the tape, the sensors never come loose or leak.
We are running 100psi in the G614s. These sensors are used by OTR rigs and Class A motor homes requiring higher pressure.

[navybanker]

I called TST and the lady said they were shipping new monitors. Guess I will use the teflon tape and soap and water check before our North West trip. If I can hear the air leak it is really coming out! Thanks,

[swanny]

The use of teflon tape on parallel threads will very seldom seal the threads from leaking. Valve stem are parallel. Teflon tape is best used on pipe thread ( tapered ). The tape kind of lubricates the threads allowing them to be put together tighter, thus making a tighter seal. The seal on the sensor comes from the rubber seat washer against the valve stem. Yes I have had a couple with milky white seals leak. I found by looking very close that they either had a crack or a tiny piece hanging loose off the seal. The Black ones work as advertised. This year i started putting a tiny bit of o-ring grease on the top of the valve stem to cut the friction between the rubber and the metal valve stem. I do check tightness before every trip and during.

kevin

[bncinwv]

Just checked our sensors and they have the black seals on them so I guess we are in good shape. Again, thanks for the heads-up.
Bingo