Metal dust caps

[Redboy]

if you are going to fit metal dust caps, do use copper grease and check them regularly. Having been told by ex-Police motorcyclist that they are an important piece of safety kit, I fitted them to my car, also because they neatly matched the paint colour. Despite noticing them getting tight and greasing them, the two rear caps oxidised and welded themselves to their valves stems, necessitating a trip to the local tyre bay today to have them pulled out and replaced. Not expensive, just annoying. On the plus side there's still 4-5mm on the rear Potenzas and the discs are unmarked at nearly 21000 miles. Definitely replacing them with Goodyear Eagle F1 whuch have been a revelation, being much quieter and giving better grip. 

[octyal]

Already found that one out the hard way. Managed to remove them with careful use of a hacksaw and a pair of wire cutters.

[BNT1985]

Got plastic dust caps, why would you buy metal other than for looks?  Are there any practical advantages?

 

My car came with Eagle F1's on it, I agree they are very good when they need to be replaced they will be F1's again.

[SaffronSkoda]

I purchased these nickel plated brass ones 3 years ago:

http://www.vanstyle.co.uk/van/nickel-plated-valve-caps-p-4536.html

I use no grease, just wipe with WD40, the chrome has slightly dulled but no corrosion.  I did look at aluminium caps but the almost certainty of corrosion between the aluminium and the brass valve stem put me off.

As to the question, why bother: the plastic ones are just dust caps, the metal ones are actually a second seal if the valve fails or leaks. I also just nip them with a spanner so they cannot be removed by hand by all and sundry.  Lastly I think they look good, the ones I received were boxed in Nissan GT parts livery.

 

[Redboy]

On 3 April 2017 at 17:20, BNT1985 said:

Got plastic dust caps, why would you buy metal other than for looks?  Are there any practical advantages?

 

My car came with Eagle F1's on it, I agree they are very good when they need to be replaced they will be F1's again.

 

22 hours ago, SaffronSkoda said:

I purchased these nickel plated brass ones 3 years ago:

http://www.vanstyle.co.uk/van/nickel-plated-valve-caps-p-4536.html

I use no grease, just wipe with WD40, the chrome has slightly dulled but no corrosion.  I did look at aluminium caps but the almost certainty of corrosion between the aluminium and the brass valve stem put me off.

As to the question, why bother: the plastic ones are just dust caps, the metal ones are actually a second seal if the valve fails or leaks. I also just nip them with a spanner so they cannot be removed by hand by all and sundry.  Lastly I think they look good, the ones I received were boxed in Nissan GT parts livery.

 

 

22 hours ago, SaffronSkoda said:

I purchased these nickel plated brass ones 3 years ago:

http://www.vanstyle.co.uk/van/nickel-plated-valve-caps-p-4536.html

I use no grease, just wipe with WD40, the chrome has slightly dulled but no corrosion.  I did look at aluminium caps but the almost certainty of corrosion between the aluminium and the brass valve stem put me off.

As to the question, why bother: the plastic ones are just dust caps, the metal ones are actually a second seal if the valve fails or leaks. I also just nip them with a spanner so they cannot be removed by hand by all and sundry.  Lastly I think they look good, the ones I received were boxed in Nissan GT parts livery.

 

 

A traffic police officer explained that they seal better. They certainly did seal too well. As the wheel rotates the valve opens under centrifugal force and a good seal is preferable. 

[BoxerBoy]

1 hour ago, Redboy said:

 

 

 

A traffic police officer explained that they seal better. They certainly did seal too well. As the wheel rotates the valve opens under centrifugal force and a good seal is preferable. 

 

I think that's a bit far fetched. If anything, the rotational force would keep the plunger closed - push in to release air you know 

 

Proven to be ok day-in and day-out by millions of vehicles going about their business without their tyres deflating.

[Redboy]

9 minutes ago, BoxerBoy said:

 

I think that's a bit far fetched. If anything, the rotational force would keep the plunger closed - push in to release air you know 

 

Proven to be ok day-in and day-out by millions of vehicles going about their business without their tyres deflating.

 

The main thrust of my post was to highlight that they can weld themselves on rather than get enmeshed in a physics discussion. I can only take the word of a traffic officer and hope he's not a fantasist. Nuff said. 

[Ootohere]

So someone with an interest can maybe discuss motorcycle valves which point into the middle of a circle and go around and around facing vertically. 

and car / van valves that do not.

Likely makes not a jot of difference though if they are plastic or metal ones, but i always like at least one cap that is a valve core removal tool.

http://honestjohn.co.uk/forum/post/index.htm?t=50340 

 

Edited 4 April, 2017 by Awayoffski

[JKW]

I too, found out the hard way once upon a time - since then, a squirt of WD40 or 3 in 1 oil into the cap (then drained) with a dab of Vaseline around the valve stem followed by a nip to finally tighten the metal valve cap (to prevent theft, 'cos they do look good !) has meant no further problems in removal. Sounds a faff, but I only oil/grease them 3 times a year, so no big effort needed.

JKW

[banksie]

Are they alloy or steel caps? Alloy will react with the valve stem and corrode. Steel, good quality ones, won't!

[furn]

I have had this problem on my insignia the valve caps corroded and stuck to the stem, as i twisted it off it broke the valve stem and as they were the tpms type valves it cost me £45 to replace it, quite an expensive lesson. 

 

personally ill never use them again!

[Redboy]

18 hours ago, banksie said:

Are they alloy or steel caps? Alloy will react with the valve stem and corrode. Steel, good quality ones, won't!

Alloy, you can see the white corrosion in the original post. Lesson learnt. 

[Redboy]

6 hours ago, furn said:

I have had this problem on my insignia the valve caps corroded and stuck to the stem, as i twisted it off it broke the valve stem and as they were the tpms type valves it cost me £45 to replace it, quite an expensive lesson. 

 

personally ill never use them again!

Ouch! I tried several times but knew that I was about to break the seal and leave my car pancaked on the drive or even worse, scratch the wheel lacquer. My local firm were great, they simply stood on the rims and pulled upwards with a set of molgrips and the valves popped out without a scratch. £5 was requested, I gave him an extra £5 for a pint, well worth it. 

[KenONeill]

On 4/4/2017 at 18:31, BoxerBoy said:

 

I think that's a bit far fetched. If anything, the rotational force would keep the plunger closed - push in to release air you know 

 

Proven to be ok day-in and day-out by millions of vehicles going about their business without their tyres deflating.

Which, by a curious coincidence, is exactly the direction that the radial component of centripetal force acts in.