[BrendanP]

I was checking the tyre pressures on my 2015 i30 today and found the plastic dust caps very hard to unscrew, on some I had to grip them with pliers to loosen them. I was the last person to take them off and I didn't tighten them excessively. My tyre inflator also has a hose which screws onto the valve stem and it was binding as I tried to screw it on. It seems to be due to corrosion on the screw thread on the valve. I tried brushing off the corrosion with a brass wire brush and smeared a little silicone grease on it. This freed things up a little so that I could at least screw the inflator hose on.

Has anyone else experienced this? Before TPMS the tyre valves were routinely replaced with every new tyre, but the TPMS valves have been on since the car was new, so they've had 10 years for corrosion to set in. Is there a tool available that can clean up the threads? I have a die nut for the wheel studs which does a good job of scraping off rust and scale that builds up on the threads, it would be nice to have something similar for the tyre valves.

[I30 GD]

A correct die would probably work, as the for the valves themselves, surely when new tyres are fitted the TPMS sensor should be removed from the valve and a new valve fitted with the old sensor.
Looking at pictures online, I can see they are of a metal construction, you can purchase separate valves that screw into the sensors, around £10 for 4.
Personally I would buy replacements then ask your tyre fitter to fit them, Correct me if I'm wrong, 👍

[Surferdude]

Interesting situation and I’m keen to see if others have had this experience.

My first thought is, if the caps are in place, screwed up firmly, how did moisture get under them to create corrosion?

On a slightly different note but related, I always replace any plastic valve caps with metal ones.

[I30 GD]

Interesting situation and I’m keen to see if others have had this experience.

My first thought is, if the caps are in place, screwed up firmly, how did moisture get under them to create corrosion?

On a slightly different note but related, I always replace any plastic valve caps with metal ones.

Be very careful with metal valve caps, my son once put some aluminium ones on his car, through galvanic corrosion they fused to the brass valve stem threads and all 4 valves had to be replaced as the caps wouldn't come off.

[Surferdude]

Interesting situation and I’m keen to see if others have had this experience.

My first thought is, if the caps are in place, screwed up firmly, how did moisture get under them to create corrosion?

On a slightly different note but related, I always replace any plastic valve caps with metal ones.

Be very careful with metal valve caps, my son once put some aluminium ones on his car, through galvanic corrosion they fused to the brass valve stem threads and all 4 valves had to be replaced as the caps wouldn't come off.

Hmmm?
Having spent over 30 years in the tyre industry and advocated metal caps for most of that time and since, that’s not an issue I’ve come across. But I’ve not used aluminium ones. Steel only.

Of course, I have to ask. How often did he check his tyre pressures?

[I30 GD]

Interesting situation and I’m keen to see if others have had this experience.

My first thought is, if the caps are in place, screwed up firmly, how did moisture get under them to create corrosion?

On a slightly different note but related, I always replace any plastic valve caps with metal ones.

Be very careful with metal valve caps, my son once put some aluminium ones on his car, through galvanic corrosion they fused to the brass valve stem threads and all 4 valves had to be replaced as the caps wouldn't come off.

Hmmm?
Having spent over 30 years in the tyre industry and advocated metal caps for most of that time and since, that’s not an issue I’ve come across. But I’ve not used aluminium ones. Steel only.

Of course, I have to ask. How often did he check his tyre pressures?

OK, maybe not metal as such but aluminium caps definitely cause problems when driven through winter in the UK with the salt on the roads.

I don't recall how often he checked the tyre pressures, probably not that often.

I managed to remove 1 cap but the other 3 were welded on, it had 4 new replacement valves and plastic valve caps after.

[Surferdude]

Interesting situation and I’m keen to see if others have had this experience.

My first thought is, if the caps are in place, screwed up firmly, how did moisture get under them to create corrosion?

On a slightly different note but related, I always replace any plastic valve caps with metal ones.

Be very careful with metal valve caps, my son once put some aluminium ones on his car, through galvanic corrosion they fused to the brass valve stem threads and all 4 valves had to be replaced as the caps wouldn't come off.

Hmmm?
Having spent over 30 years in the tyre industry and advocated metal caps for most of that time and since, that’s not an issue I’ve come across. But I’ve not used aluminium ones. Steel only.

Of course, I have to ask. How often did he check his tyre pressures?

OK, maybe not metal as such but aluminium caps definitely cause problems when driven through winter in the UK with the salt on the roads.

I don't recall how often he checked the tyre pressures, probably not that often.

I managed to remove 1 cap but the other 3 were welded on, it had 4 new replacement valves and plastic valve caps after.

Yeah. Aluminium and salt wouldn’t go well together.

[BrendanP]

Just an update, I bought a 4 in 1 valve maintenance tool from Halfords which includes a die you can run down the threads to clean them up. Don't think it's a tool steel like a proper die, but seems to work. I only ever use plastic dust caps, I've heard that the decorative metal ones can corrode and jam tight on the valves.

Not sure why the corrosion is worse than on my other car which is identical and the same age. It had spent most of it's life in the Medway area which is the Thames estuary, so possibly the coastal environment with more salt in the air has promoted corrosion.

[Surferdude]

Just an update, I bought a 4 in 1 valve maintenance tool from Halfords which includes a die you can run down the threads to clean them up. Don't think it's a tool steel like a proper die, but seems to work. I only ever use plastic dust caps, I've heard that the decorative metal ones can corrode and jam tight on the valves.

Not sure why the corrosion is worse than on my other car which is identical and the same age. It had spent most of it's life in the Medway area which is the Thames estuary, so possibly the coastal environment with more salt in the air has promoted corrosion.

🤪 I’ve got one of those somewhere. Forgot it existed.