A simple thing but it could be costly to you.. BEWARE!

My mini truck is used off road.. lowering tire pressure and pumping them back up is part of the game.

This could be trouble!

This could be trouble!


It’s spring and as the weather improves, I attempt to get things sorted for this year’s use.. The Mini truck had two low tires, and as I attempted to unscrew the valve cap, I realized I had stuck ones for the first time in my life! Sixty five years of living and never once have I fought this trouble.

The problem? The cap is made of some type of alum alloy, easy to machine, longer tool life, but it can and does react with the metal used in the valve stem, so nobody.. till now has made one that I know of.

I leave it to you to figure.. was it a person who didn’t know better, or a person who didn’t care better?

If you have these, get them off your vehicle.. I have two that I have heated, and dowsed with penetrant a bunch.. no joy yet..

Updated 3/30/13

BEWARE! Ebay is full of cheap beautiful in appearance valve caps! They are made of Aluminum and at least in my climate, a generous amount of aluminum oxide was formed and made it impossible to take the cap off!  

After some days of soaking with penetrant, Brian W. said he had read that Ammonia could break that corrosion between alum and steel, and suggested I give it a try with alum to brass. I used a die grinder to cut off the end and then a Q-tip to keep swabbing on ammonia, within 2 minutes the bond began to break, and I kept twisting the cap back and forth and finally the cap was off.. did the other side and now I’m set to put on stainless steel or plastic..

Is this a link to more trouble?  I dunno…..   http://www.ebay.com/itm/New-4-pcs-Hexagonal-Ventil-Valve-Cap-For-Auto-Car-Truck-Silver-/271036711380?pt=Motors_Car_Truck_Parts_Accessories&hash=item3f1b0c01d4&vxp=mtr

Thanks for the Ammonia Brian!








This entry was posted in DIYer Skills, Strange Stuff, Things I Hate! and tagged , , . Bookmark the permalink.

4 Responses to A simple thing but it could be costly to you.. BEWARE!

  1. Kurt says:

    I got an education on this issue myself,although in my case it was a table saw that taught me to look while putting together and to think ahead instead of hurrying so that you can get that 2×6 ripped to size.

    A great many of the newer stationary power tools make great use of cast and extruded aluminum,in the place of old fashioned cast iron. Nothing wrong with that-aluminum ( and the various die-casting alloys ) are light weight,and have more than adequate strength for the needed application. As well,they’re easy to fabricate,and the lower weight makes for lower shipping costs,and a piece of equipment that’s easier to move around than a ferrous metal equivalent would be.

    However,the bolts and nuts used to fasten the various components together are still made of steel. And a steel bolt or machine screw,when inserted into a threaded hole in aluminum or zinc,will eventually ( and sometimes not all that eventually ) freeze itself into the hole,due to the reaction mentioned in the article.

    The solution is a simple one,available at almost any hardware store. Before assembling anything,make sure you have a can of anti-seize compound at your side,and make sure that any bolt or machine screw gets a glob of the compound smeared on it before being threaded into the hole and tightened. ( This isn’t a bad idea for pretty much all nuts and bolts in general-it saves a heck of a lot of headaches when trying to take something apart a couple of years down the road. )

    The hell of it is that I knew that freezing phenomenon could and would happen,however,I was in so much of a hurry to get my tablesaw together so I could get to work,that it completely slipped my mind. And a few years later,my thoughtlessness got repaid with a piece of equipment that is-speaking charitably-of drastically reduced utility.

  2. Greg says:

    My friend purchased a metal alloy piece from eBay and was trying to explain to me what a problem it was. I never do my own mechanics but I’ll send him this link, might make him feel better to hear he’s not alone.

    • George B. says:

      Greg… do tell him if my friend and neighbor hadn’t suggested ammonia, I would have likely taken in the tires and had the valve stems replaced.. I still had to cut the tops off the caps to let the ammonia work, but so much easier than the other fix..

Leave a Reply