Tyre dust caps warning

Anthony1

Anthony1

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I have a blue van and pimp it up a little. I added blue VW hub centres and blue aluminium dust caps - really pimped!

However, On going round to test tyre pressure, three dust caps came of relatively easily, one would not budge, I used Rust Free, pliers, grips etc, then I tried grinding it off. I got down to the brass thread gave it a twist and pull and out came the whole valve and down went my tyre.

My son who is a motorcycle mechanic says they never used metal dust caps.

I went to to National Tyres who fitted a new valve (for free) as it was long one, not a short one (I didn't tknow there were different types). And they said, they never used metal dust caps.

I now have plastic dust caps.

I useds a trolley jack to jack up the van so I could take the wheel to National tyres. Even consulting the handbook it was not onbvious where the jacking point is. I did manage to sort it all out, but the trolley jack was at its maximum. Next time mI will slip a piece of wood under the jack (for more height) in future as there wasn't much cleareance with a fully inflated tyre.
 
Here is the reason why:
Thread galling occurs during installation when pressure and friction cause bolt threads to seize to the threads of a nut or tapped hole. It is also known as "cold welding". Once a fastener has seized up from galling it is typically impossible to remove without cutting the bolt or splitting the nut.
 
Thank you.

I now have first hand experience of it.
 
I think the problem here is the aluminium cap on the steel valve stem. Steel valve caps are fine; in fact my BMW motorcycle came with them from new.
 
Vasoline will prevent bi metallic reaction, smeared into to valve cap
 
I think the problem here is the aluminium cap on the steel valve stem. Steel valve caps are fine; in fact my BMW motorcycle came with them from new.

You would have thought some members would have remembered this from the Roof Corrosion saga...;)
 
You would have thought some members would have remembered this from the Roof Corrosion saga...;)

The irony there is my son is a BMW motorcycle technician.

I was not familiar with the roof saga.
 
You would have thought some members would have remembered this from the Roof Corrosion saga...;)
True but for galling to take place there needs to be movement to start with - not sure movement was ever identified as a major component of the roof corrosion issue. Anyway my experience is between Brass and Stainless Steel in the water distribution industry. Can be an operational nightmare when components you assemble finger tight simply can not be shifted for final assembly without fear of serious damage necessitating complete replacement. All to do with electrochemical corrosion. It's a complex subject.
 
I've got some of them anti let your tyres down dust caps. Anti theft I think they're called.they seem OK at the moment. As for the trolley jack mine gives loads of clearence when using the jacking points. I removed all my wheels to check none were seized on the hub.suppose it depends in the jack.
 
True but for galling to take place there needs to be movement to start with - not sure movement was ever identified as a major component of the roof corrosion issue. Anyway my experience is between Brass and Stainless Steel in the water distribution industry. Can be an operational nightmare when components you assemble finger tight simply can not be shifted for final assembly without fear of serious damage necessitating complete replacement. All to do with electrochemical corrosion. It's a complex subject.


Such knowledge here.
 
I've got some of them anti let your tyres down dust caps. Anti theft I think they're called.they seem OK at the moment. As for the trolley jack mine gives loads of clearence when using the jacking points. I removed all my wheels to check none were seized on the hub.suppose it depends in the jack.
I had them, they all seized, new valve stems all round..
 
If your trolley jack is struggling to lift the van high enough it could well be that it's lifting capacity is too small as well.
 
Scumbag stole 2 of my VW dustcaps and replaced with their own plastic ones!
 
Aluminium vs steel vs water do not mix......hence the ali dust caps welding themselves to the steel valves :Stig
 
Did put some on our Cali but got Nicked, so ask a thief LOL
back to plastic !
 

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