Stuck/ corroded Valve Caps

[Samstan]

Help! My Octavia came (2nd hand) with metal valve caps with the Skoda logo on. Last week the tyre pressure warning came on as the car was heavily loaded. I pumped up the front tyres but cannot move the rear valve caps (even with pliers and WD40). I think they may have corroded onto the tyre valves. Can anyone recommend anything that might dissolve the corrosion or am I going to have to try the garage?

 

thanks

[Ootohere]

Boil the kettle and then pour boiling water on the cap and try loosening the cap. 

[Samstan]

Thanks I’ve just tried that but didn’t work ☹️

[Ootohere]

@Samstan

The next trial is do it again with boiling water and then pour cold water on right after.

[Samstan]

Still a no go ☹️

[inspectorman]

Rotate the wheel so that the valve is at the top of the wheel. Now put a small amount of PlusGas on the edge of the cap and it will work its way down into the corrosion. After 15/20 minutes have another go.

 

I personally wouldn't be happy about the valve after you'd got the cap off and would be saving up for a new valve at the tyre fitters.

[Warrior193]

If staying with metal caps once you've got the seized ones off, put a smear of copper ease grease on the valve stem threads before replacing.

[Modders]

1 hour ago, Warrior193 said:

If staying with metal caps once you've got the seized ones off, put a smear of copper ease grease on the valve stem threads before replacing.

 

+1 - This 👆 

Or a little smear of Vaseline on the threads as it can be a bit ‘cleaner’.

I also remove mine towards the end of October and put the plastic ones back on until after the frosts/gritting has stopped again.

 

[Samstan]

3 hours ago, Warrior193 said:

If staying with metal caps once you've got the seized ones off, put a smear of copper ease grease on the valve stem threads before replacing.

Once they’re off it’s black plastic all the way!

[Samstan]

6 hours ago, inspectorman said:

Rotate the wheel so that the valve is at the top of the wheel. Now put a small amount of PlusGas on the edge of the cap and it will work its way down into the corrosion. After 15/20 minutes have another go.

 

I personally wouldn't be happy about the valve after you'd got the cap off and would be saving up for a new valve at the tyre fitters.

This stuff? https://www.screwfix.com/p/plusgas-formula-a-dismantling-lubricant-400ml/485ht
 (& thanks)

[Paws4Thot]

1 hour ago, Samstan said:

This stuff? https://www.screwfix.com/p/plusgas-formula-a-dismantling-lubricant-400ml/485ht
 (& thanks)

Yes, and well worth the money for the time it will save on your first couple of jobs using it.

[Okedokey]

Ranex or any rust converter will losen them, but i'd try some basic WD40, or other penetration oil.  Let it soak a bit.

[Samstan]

6 hours ago, Okedokey said:

Ranex or any rust converter will losen them, but i'd try some basic WD40, or other penetration oil.  Let it soak a bit.

Thanks tried all that and nothing worked so it was a garage job for new valves. Cost me £30 for the 2 wheels so could have been worse!

[Warrior193]

I prefer the aftermarket, metal valve caps as they usually have an internal O-ring seal fitted - but you need to watch out for them seizing onto the stems. 

[J.R.]

Do you mean you prefer the look of them?

 

If so then preventative maintenance is the price to be paid.

 

Because standard plastic valve covers have a built in sealing ring (as do the AC port caps) and do not seize with corrosion.

 

 

[Samstan]

Plastic all the way for me now!

[Okedokey]

if you're committed to metal ones, apply some dielectric grease on the threads before install