Slow leaks caused by TPMS valves on a Hyundai i-30

While replacing a tyre for a customer, his next door neighbour came and asked if I could check the valves and seals on his tyres as they were constantly losing air.  I wasn't able to do it that day as I was fully booked, but he was booked in for the next day.

When I arrived at his address he told me that he had inflated all of the tyres to 32 psi the night before. I checked them and they had all dropped to around 27 ~ 28 psi.  I jacked the car up and took the wheels off one by one, and checked all around the seal areas, these were OK, so I then checked around the TPMS valves.  All of them were leaking from around the bottom of the stems. This is often found on older valves where the rubber seals have hardened allowing air to leak.  This is why it is recommended to have the TPMS valve serviced every time new tyres are fitted.

To solve the problem we remove the tyre and the TPMS valve and sensor, we then fit a new valve stem and sealing nut to the sensor (This includes a new rubber seal) once re-assembled the tyre is put back on the rim, it is re-balanced and the wheel is put back on the car. 

Once the wheels were all back on the car, I was able to reset the TPMS system on the dash. This should solve the problem for the customer. 

Once complete I checked all of the tyres, wrote out an inspection report and took a payment from the customer.