So I have tried to search on the Forum to see if anyone has run into this before, but didn't find anything so I'll throw it out as a new topic.

When I bought my previously owned 2019 F54 S in June from my Mini dealer, I did manage to negotiate a new set of tires. Within 10 days I needed to go back as I was not able to maintain tire pressure in all 4 tires. Mini Dealer / Servicing is about an hour and half to two hours drive each way, and I have a 60 day limited warranty so the replacement valves were free.

I was told "batch of bad tire valves" in 3 wheels, 4th was fine just needed filling... but it wasn't and I needed to go back. Service folks have been very nice to work with.

Fast forward have about to 10 days left on my warranty, I have now replaced 5 of the valves ( plus I was told 4 new ones were installed with new tires so that equals 9 "bad tire valves") and several trips to the dealer ... AND I just called today as I have yet another leaking valve. That's 10!! Weird thing is this valve wasn't leaking last week when I was there. I've gotten good using soapy water and spray bottle to find the leaks... check tire pressure every drive.




Has anyone heard of anything like this before?

It seems odd the valves are not bad from the start / once installed, but they seem to go bad over time. The new one I called in today is at least two weeks old.

I keep being told it is "bad valves", but I now wonder if it is the wheels? Valves have been replaced now on all 4 wheels.

Thanks for any thoughts.

Rob

 

Something isn't adding up with your situation, IMHO. I can see if they have 1 or 2 bad TPMS units, but a whole batch says something else is going on. My guess is that there is something not being put together properly during the installation of the unit into the wheel, whether that is putting a seal in the wrong location, leaving a seal out, overtightening the mounting nut or something else. I have never pulled my own MINI sensors, but all the ones I have seen are very simple, yet I am sure folks figure out ways to mess that up.

Are the bubbles coming from inside the stem (i.e.- through the Schrader valve) or the interface between the stem and rim? I wonder if they have different sealing gaskets on the sensors depending on the rim they are installed on? This could explain using the incorrect seal for your rim and how it might work for a bit of time, but then start leaking. Hope you get this resolved and let us know what they end up finding as the real root cause.

 

So the air leaks and bubbles are not coming out of the Schrader valves but always from the space between the valve stem and the rim. None of the TPMS have been replaced until today. I’ve not been able to find a schematic drawing from a parts catalog ( not sure that exists for Minis) but as described to me once the new valve stem is pulled through/ seated into the rim there is an outside locking nut to hold the stem in place that’s tightened later, then the pressure sensor (a separate piece from the valve stem / valve) is attached to the inside of the wheel and then to the valve with another locking locknut. Saw a YouTube video on leaking valves and while it was a GM wheel it also was two separate parts. I think the design allows you to reuse the TPMS because they are expensive and just replace the valve stems when you get new tires.

Today when I took the car in the chief mechanic worked on it and he found that for this leak it was caused by the valve stem not being tightened down correctly, causing the the valve stem to not be seated perpendicular to the rim, nor seating correctly into the TPMS and therefore creating a gap for the air leak.

Both the stem and sensor were replaced, drove home and all seems ok.

The problem seems to have been a real head scratcher for the service dept and no one thinks it is “bad” wheels. Perhaps the tightening of various locking nuts is that exacting, and maybe there were bad valves or both. It has certainly been a challenge and we’ve now replaced 10 valves. The service people have all been great to work with and I hope now the pressure holds on all four tires.

So is there a link to a parts catalog for Mini’s that includes schematics of how they all fit together?

Thanks!
Rob

 

So to answer my own question this morning did some quick searches with the help of ChatGPT AI and found a BMW parts catalog with schematics.

Paste RealOEM.com into your browser and enter the last seven characters of your VIN and it will take you to the correct portion of the catalog.

Here's a picture of the wheel and valve parts, the TPMS sensor while shown does not have a part number here, but you can see that valve and stem, valve core, sensor are all separate parts from the sensor. There will be a sensor section with part numbers somewhere else.

 

Well, there you go...improper installation. My guess is that the previous techs were not using a torque wrench to tighten the stem nuts. Likely the seating torque on the valve stems is above what the average tech feels is tight enough. With how fragile some valve stems can be, I can understand being shy when tightening w/o an actual torque control device in your hands as you don't want to break/damage the new stem. I am very guilty of not following actual torque specs on my own vehicles for a lot of applications and using the simple 'gudntite' method. Lug nuts are one thing I use a torque wrench on 100% of the time, but an oil drain plug is one I will pass on, FWIW.

Anything with a rubber/elastomer seal really needs to be installed with a torque wrench/screwdriver, since the joint was designed with a fairly specific clamp load to get the seal to do its job properly w/o failing (i.e.- loose or squished out of position or damaged). I have been responsible for assembly of gas powered appliances for just over 20 years and for reliability and liability for that fact, have always specified torque controlled tools for assembling plumbing connections. It is the ONLY way you can ensure an assembly was tightened consistently day in and day out.

I hope this will be the last time you will need to visit the dealer for this particular issue.

 

Ted - Yes so "improper installation" had crossed my mind also, but I had not thought of a torque wrench being involved for the stem locking nut.

I had watched several YouTube videos on fixing leaking tire valves, removing the valve stem, removing the Schrader valve core, removing the TPMS, and then reassemble but never saw a torque wrench.

Makes sense for gas appliances for sure and whenever I have done any wrenching on my cars and bicycles I've always looked to find the nut / torque values.

Thanks for your thoughts on this and hope that this problem is solved also.

Rob

 

I would hope the design world (i.e.- my fellow mechanical engineers out there) wouldn't drive what should be a 'simple' design to require a torque wrench, but then again there is plenty of evidence of this in the automotive world where an overly complex design is let loose into the wild. I too have never seen a torque wrench get any closer to a valve stem than the lug nut, but it would be interesting to see if there would be any improvement by checking that connection to the recommended torque value. Now, if the seal is 'directional', then we have a straightforward overly complex design that is just waiting for failure. You have to design for the intended audience (i.e.- user/mechanic/technician).

One comment that has lived on in my brain was from one of my senior design class professors, "A complex mechanism is very simple to design, a simple mechanism is very complex to design." That quote/comment is always whispering in my brain when I design a new assembly fixture or equipment and has helped me sit back and re-review my designs to make them simpler.