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The mkiv Supra Owners Club

Ridiculous problem


Ian C

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So, I get my new Rays wheels a couple of years ago, and almost instantly while parked at my parents someone nicks two of the valve caps. Shiny anodised blue aluminium they were too. So me being me I just buy a pack of Halfods boggo silver ones and stick two on the fronts while moving the remaining blue ones to the rear.

 

Now I find that the bladdy steel halfords ones have corroded on to the aluminium valve stems due to the miracle of that electrical charge thing between two different metal types (can't recall the term - electrolysis? Surely not). Anyway I now can't get them off, even with pliers the whole valve rotates in the wheel rim. Sigh.

 

So I intend on very carefully dremelling the caps in half while avoiding the thread on the stems. Fun! If anyone else has a better idea, feel free to contribute. I'm only posting this because I've not talked about my own car for ages :)

 

-Ian

 

PS I've had most of the paintwork redone to clear up a shedload of stonechips and shocker - no more decals on the door for me :shock:

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Can you get a hold of the stem of the valve with a set of pliers? I had this a few years back. I used mole grips on the stem and pliers on the end.

 

If the worst comes to the worst, cut it off and get it replaced.

 

Alas, I did think of the dual grippy thing approach, but that'll probably damage the shiny blueness of the stem, plus there is a chance a minor slip with pliers will damage the lovely Rays alloy as well. So it's still Dremel winning the race for me :)

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Alas, I did think of the dual grippy thing approach, but that'll probably damage the shiny blueness of the stem, plus there is a chance a minor slip with pliers will damage the lovely Rays alloy as well. So it's still Dremel winning the race for me :)

 

Ahh yes, i see your dilema now :(

 

Is it possible to buy the valve's?

 

I would still go with dual grips, cept i would cover the valve with a cloth or something like that. We use pliars with wipes all the time, all you have to be careful of is crushing. Hopefully a little bit more grip is all that you would require though. Have you tried a little heat?

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Ian, would heating the valve cap gently with something like a lighter, blow torch on low setting help at all. As the different metals will expand at different temperatures, this should free up the threads hopefully.

 

There's a rubber insert in the valve so you can't heat them.

 

Personally I'd just buy some replacement valves and caps from t'net and give your local tyre place a tenner to swap them over.

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i had this problem with cheapo valve caps i had to dremel mine off too, make sure you place a thick rag around the area just incase the dremel slips off dont want a nasty sratch on the wheels, just take your time do a little at a time i found once i got close to the thread they came off by hand, have fun :D

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I too would suggest a 2-plier approach as Scott said. I'd wrap any nice metal bits in a thick rubber band, which will protect them from the pliers and may also help the pliers grip. Could you use a cloth to protect the wheels from damage, or would it get in the way too much?

 

Or, instead of heating the joint, you could cool it right down with ice. You'd be taking a gamble that the difference in metal contraction works in your favour though.

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Its called dissimilar metal corrosion in my industry and we use JC5A to stop it commonly known as yaksh*t. If you want the caps back just get the tyre place to cut the valve out from the inside of the wheel and stick the cap (I assume its a hex head cap) in a protected jaw vice and get a decent gripper moleys on the valve stem or drill a hole in the metal part and stick a drill bit through the stem to turn it. YOu may require some wd40 penetrating oil to loosen it up a bit. Spot of WD40 wouldn't hurt the on car removal either.

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Can a mod move this to technical? ;)

 

The freeze spray idea might work, as because the as ali is inside the steel cap, it will contract much faster than the steel (hence heating them up would only make things worse, even if it were possible). Freezing might open up a gap between the two. I would imagine that freeze spray wouldn't hurt the valve innards, either.

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An excellent set of responses, thank you :) Putting cloth around the wheel when Dremelling is a good idea that for some reason hadn't occured to me yet. Usually that sort of idea crops up just after the "tzzzt" noise.

 

The valve caps that are stuck on are the crappy Halfrods ones that cost like £3 for all 4, so I'm not destroying the Rays shiny anodised valves or paying a garage to pull the tyres off without being able to lower the pressure first in order to save them :D Snapping the valve sounds like a bad idea as well so that counts out gruntwork with pliers (plus I can see myself damaging a wheel easily that way!)

 

I'm still going to go for the Dremel microsurgery first (now with added cloth!), although the freeze spray idea sounds intriguing.

 

Galvanic reaction, thank you :cool:

 

-Ian

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My ex's wheels did this exact thing. She took it to a local tyre place, and they cut the valves off, which allowed the tyres to deflate, then replaced the valves and started again.

 

Cheap, easy and no damage to the wheels, but I'm sure you know what you're doing though :)

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if your going with the Dremel grinding discs make sure you wear eye protection, i had one fly apart a while ago and a bit ended up embeded in the insulation in the garage roof :blink:

 

Yep cheers mate, I wear eye protection for drilling and sanding, never mind grinding! I had a close call while shooting one day when I got part of a bullet come back at me and lodge in my cheek about 1" under my left eye :shock:

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Ian, would heating the valve cap gently with something like a lighter, blow torch on low setting help at all. As the different metals will expand at different temperatures, this should free up the threads hopefully.

 

Aluminium alloy expands more than mild steel, so they'd become tighter. Good old pull through rubber valves with black plastic caps, Lovely jubbly :)

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