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Tyre Pressure Drop

9K views 25 replies 8 participants last post by  Wiggy 
#1 ·
Back rear tyre always seemed to want an extra pound or two of pressure compared to the rest, but recently, the warning light came on and pressure had dropped to 17 lbs. Reinflated and 2 weeks later. Warning light came on again.

I couldn't see any sign of object penetration but I knew I had an old valve tool somewhere in the garage that I hadn't used in 15 years. A search located it and I gave the valve a slight tighten about a week ago. Pressure has remained up ever since, so it's worth checking the tightness of the valve insert if a tyre is going down before taking it to the tyre dealer.

Sometimes you get leakage around the beading or the valve seat, but not in this case.
 
#4 ·
Much the same as round the bottom of your valve itself. Old, simple but effective things like this seem to be lost.
 
#6 ·
Tyre pressure is still dropping. Seems like the valve is leaking around the joint with the wheel. Corrosion I guess. Ford have said a new valve is £24 but the base (without the sensor) is £7. Plus they will probably charge main dealer rates to fit.

I'm thinking of deflating the tyre and removing the valve, then cleaning the seat and refitting. Is there anything I can put between the valve and the seat to improve the seal?
 
#9 ·
Thanks Maxfan. My tyre dealer (Discount Tyres) said they won't touch these valves even though I bought 2 tyres from them. They said to take it to the main dealer.
 
#12 ·
Leaks around the valves are quite common on the alloys used on the Bmax, and maybe some other models ?
I had a front wheel with a very slow pressure drop. I took it into my local tyre dealer, he removed the valve
cleaned the seating and replaced it. Now I have a similar problem with a rear tyre.
 
#13 ·
Eventually got fed up with the pressure loss and had a standard valve put in. I was sure there was an option in the menu to turn the sensors off, but now found there isn't. I haven't checked the manual or anywhere else yet, but does anyone know how to turn the pressure warning system off ,e.g.removing a dedicated fuse, disconnecting a wire, etc.
 
#17 ·
I don't think you can turn off the tpms, since it's been mandatory for 'new' vehicles in EU since november 2014
but I think it can be turned off in the earlier cars.

ford changed from a wheel speed sensing system, to a valve mounted system, as tpms was becoming mandatory.

just putting a sticker over the light would be an MOT fail

as standard, ford valves with sensors have a rib on their rubber body, or are a bolt in type.

most informative (and readable) article I have is...
https://www.schradertpms.com/en-gb/company/press-room/tpms-legislation-overview-eu
 
#18 ·
Thanks Gremlin. Not the answer I was hoping for, so may end up changing the valve again then.

As it happens, I am currently looking at a new Puma, so it may depend on whether I take the plunge or keep the BMax for another year or two.

B Max is due for a service in December, so I could ask them to replace the valve then depending on how annoying I find the start up warning. I'm not too bothered by the yellow 'I' light.
 
#19 ·
Tyre dealer gave me the old valve and sensor, so i assume that if i give the sensor to Ford when it's serviced and MOT'd they will fit it to the new valve and not charge me for the whole thing.
 
#20 ·
Odd. went to the ford dealer to test drive the puma earlier and left the salesman my keys as security and to enable him to value the B Max.

When I left, the tyre pressure system warning had disappeared and hasn't appeared since. Did he find a way to switch it off or does it disable itself after a while? Strange coincidence if it did.

Thoughts?
 
#22 ·
Not too sure that this is the answer you are looking for, but i found this video on "the tube" about resetting the tpms --
[ame]https://www.youtube.com/watch?v=AbrWy7FjlUs[/ame]


You may have seen it already but it could help others that come across the warning light.
 
#23 ·
Thanks Wiggy, I know how to do that, but it won't work if a sensor is missing.

The Puma was superb Hywel, But I would need to sell the B Max privately to get to the price agreed and might find that a bit tricky in a lockdown. Also with Europe going into gradual lockdown, whist Ford estimate delivery mid December, I can see myself waiting months before it is built or shipped It's a lovely solid car though and makes the B Max feel more like a tin can by comparison. The regenerative braking is interesting, especially in sport mode, but does seem strange when it slows down so quickly when you take your foot off the accelerator.

I've loved every minute I spent with the B-MAX though and am quite happy to stick with it for a while longer as apart from needing to replace the tyre valve it really is as good as new.

Tyre warning light is back BTW
 
#25 ·
If I had a spare tyre, then maybe Wiggy, but I'm just inclined to have a new valve put in at my next service. I've put a lid on the Puma deal due to the health situation as 1. I won't be able to sell the B Max in lockdown and 2. I have no confidence in the Puma being delivered for several months. Will see how things look next year
 
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