Checking the tyre pressures on my van tyre earlier, all but one of the dust caps came off easily apart from the one tyre that looked low in pressure. It looks like a brass? Cap, the others are plastic. I’m guessing it’s corroded to the thread. Tried pliers but the valve looked like it was twisting. Any tips on how to release it or am I taking myself off to the tyre fitters tomorrow?

Pliers to hold valve stem and one on the cap after a few squirts of gt85?

Obviously don’t be too rough with the pliers!

jizz in a bit of GT85 (or posher penetrator if you have it)

hold valve with 1 set of pliers and turn cap with another ?

cut off top of cap with dremmel ?

cut slit up side of cap with dremmel and “peel” it off the valve stem ?

drill off top of cap from above ?

Cheers chaps. I tried the pliers and only have wd40 so will see if it’s helped in the morning. Failing that, Dremel…. Failing that, tyre shop…. Providing I don’t slice the valve off with the Dremel

Avoid metal valve caps for this reason, I found out about a year ago when I could only get one of the four off to check pressures. Tried all of the above but they wouldn’t budge. Took into a tyre shop and they managed to get one off ok but had to get two new valves fitted.

I will Deffo be replacing it with a plastic one. Seems strange only one of the four is metal. little things sent to test me today

If using metal caps put a dab of grease on the threads. Too late for the OP but pliers beneath the cap and another pair to twist the cap off.

Pfft. Try changing the passenger side headlamp bulb on a Peugeot Partner van. Some numpty has put the damn fuse box in the way and I now have no skin on my knuckles. Plus my neighbours have discovered just how much I’m prepared to swear when angry.

As said above, two sets of pliers should sort it.

2 sets of pliers couldn’t do it for me. Mind you, a new valve was really cheap and quick.

Nothing but plain black plastic ones for me now.

It’s way more common than you think, people like their car brands on their valve caps and buy a set for £2 off e bay.
When it gets really expensive is when the wheels have tyre pressure sensors and the seized tyre valve ends up costing £150 per wheel to replace and reprogram. Also most cars won’t let you de configure the function so if you fit standard valves the dash warning lights up like Xmas tree every time you start.
If non sensor get the valve replaced or cut the cap off as someone has said because the corrosion usually is far to great for them to move without ripping the valve off and most people turn them with pliers until they rip the valve and deflate the try on there drive.

Ah, yes, as chrisdiesel said, the ones with sensors are expensive.

I (metaphorically) shit myself when I first googled ‘stuck dust cap’. A big sigh when I realised the regular low-tech ones were a couple of pounds.

In the end, rather than try too hard and give myself a flat tyre on the driveway, I just drove to a garage and accepted defeat.

Womble how did you get on, suspense is killing me!

dickyhepburn – Member
Womble how did you get on, suspense is killing me!

Just got back from the garage…. That should give you an idea as to how I got on with my own hamfisted attempts with the pliers

Avoid metal valve caps for this reason

No need to avoid metal valve caps, just put some grease or coppaslip on the threads, like you would do with any metal to metal threads.

valve caps are soft alloy so you should be able to use snips to chop it up.

I’d have tried hot water from the kettle before finally giving up.

…just put some grease or coppaslip on the threads, like you would do with any metal to metal threads…

I would dispute “any” in the above statement. Obviously not the case with a valve dust cover, but lubing metal to metal threads and then tightening to a specified torque will pretty much always result in overtorquing

okay ‘many’