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On checking the tyre pressures on my 2004 Mk6 Ford Transit based motor home I discovered the rear nearside inside tyre valve had failed.  The valve stem was still in place in the wheel rim, however the valve section itself including the extension had gone and obviously the tyre was totally deflated.  Fortunately the chassis is double wheeled, however the only indication I got was a slight vibration at under 45 MPH, over 45 this vibration strangely disappeared.

Is anyone else aware of this potential problem? 

Checking on the web I found the following, which seems to prove there has been or indeed may still be a problem with this type of valve.

There is a widespread awareness of this problem throughout the UK tyre-fitting trade and it is likely that the number of failures in this country alone is (at minimum) in the hundreds. The failures are confined to the TR-600 pattern high-pressure 'snap-in' valves fitted as original equipment (OE) to many Mk 6 Transits. The TR-600 HP valve is a standard design produced by various tyre-valve manufacturers and is designed for inflation pressures up to 100psi. Its most common light commercial vehicle application in the UK is on Mk 6 Transits, but some current Renault Masters are also fitted with TR-600 valves as OE.

After the TR-600 valves on my own motorhome had been replaced I dissected all 5 valves and compared 'good' with 'bad'. Each valve has an 18mm long section of brass stem penetrating into the rubber base. The 3 valves that had continued to function satisfactorily had the full length of this section of stem firmly bonded to the surrounding rubber. However, the 2 failed valves had just a narrow ring of rubber bonded around the stem where it emerges from the top of the base. The lower 17mm or so of stem and the rubber that enclosed it were both totally smooth with absolutely no indication of bonding between stem and base having taken place.

It is perhaps worth emphasising that, because these failures are not tyre-pressure-related, a fault-free TR-600 pattern valve will be perfectly adequate for Transit usage as recommended tyre-inflation pressures for Transits are well below 100psi.

Thanks for that information Royal 6.

Do you know if there is any danger related to replacement tyres (tubeless I think) on an older model Transit?

Kath