Trying to check tyre pressures and one of the valves won't come off. They have metal caps on and one of them seems to have jammed onto the stem. When I get a socket on it (they are 10mm Hex caps) the whole stem, which is also metal, rotates. I've tried grabbing it with some needle-nose pliers but it still turns.

 

I took the car to Prodrive who recommended I get a replacement stem, in case the existing one is found to be damaged when they remove the tyre. Looking online there are about a thousand different kinds. Does anybody know what sort I need, or are all the makes essentially the same?

 

The wheels are marked "Versus" and I've attached a couple of pics.

 

Thanks!

 

Some of them valve caps have little allen screw for anti theft

You'd be better borrowing some small mole grips, sounds like you're not gripping so well with the needle nose, I do understand you also do not want to compress the stem.

Exactly right, the last thing I want to do is damage the stem since it's currently a good seal! I did them all up hand tight after checking pressure some time ago but this one has frozen on. I'm going to try heating it with some hot water to see if the cap will expand and loosen...

 

... hot water doesn't work :(

Edited August 5, 201510 yr by Scarecrow

Problem is the cap and the stem are made from different metals so when they get moisture between them galvanic corrosion occurs and the two almost fuse together. Last time I fitted ally valve caps to a car I had to destroy the valves to get the caps off. I won't fit ally caps to a car again. I guess if you put something like lithium grease on the threads it might stop it happening

Trust me once I get the damn thing off plastic caps are going back on! The metal caps are what were on the car when I bought it, I had no idea the stems were metal too until now.

 

I've found some possible replacements for the stems on eBay, nothing specifying size so I assume one size fits all?

Trying to check tyre pressures and one of the valves won't come off. They have metal caps on and one of them seems to have jammed onto the stem. When I get a socket on it (they are 10mm Hex caps) the whole stem, which is also metal, rotates. I've tried grabbing it with some needle-nose pliers but it still turns.

 

I took the car to Prodrive who recommended I get a replacement stem, in case the existing one is found to be damaged when they remove the tyre. Looking online there are about a thousand different kinds. Does anybody know what sort I need, or are all the makes essentially the same?

 

The wheels are marked "Versus" and I've attached a couple of pics.

 

Thanks!

[ATTACH=CONFIG]89580[/ATTACH]

 

[ATTACH=CONFIG]89581[/ATTACH]

 

scarecrow where can i buy these blue valve caps?

A couple of months ago i had the same problem on my merc and no matter how tight i gripped the stem the metal cap would not shift and the last thing you want to do is overly force.

 

I ended up grinding the cheap cap off carefully with my dremel, although i did 'catch' the stem thread it did not damage it nowhere near enough for a PLASTIC cap to finger tight on !!