Stuck Schrader Valve...

[townbikemark]

So I had the tyres of my Brompton injected with that puncture prevention gunge stuff, where you're still supposed to be able to pump the tyres up like usual. Fine for a while and I can still pump the rear and it will show the pressure. The front one seems to be stuck though - one pump takes it to 90psi or so whilst another send the needle all the way to the end of the guage.

Any ideas - thought about trying this and that but don't want to just in case of damage.

Cheers.

[gaz]

If you don't already have one buy a valve core remover.

Once it's out you may find you can clean it up and get it working again. If not buy a new valve core or salvage one from a spare tube.

[Brucey]

Schrader valve cores should unscrew from the valve body. You need a special tool to unscrew them, like this;



you need to use the fitting top right in the picture above.

Before you do that, just make sure that the valve centre (which can vary in height slightly) is actually being depressed by the pump that you are using, and that when it is depressed, air can't come in and out of the tube as normal. If the valve is blocked with sealant, depressing the centre pip won't release any air; if the valve is OK it will.

Problems of this sort are not entirely unknown and are why some folk won't use such sealant in tubes BTW.

cheers

[mercalia]

happened to me; why I dont use slime

[Brucey]

FWIW having a remover built into the dustcap is very handy if you think a valve insert might come loose on the road, but the dustcap will usually be made in brass, and the correct tool for the job is normally made in hardened steel.

Obviously if you are trying to get a bad insert out of a valve stem, you may not manage it with a soft brass tool, where it will be much easier if you use the right tool for the job. So for that reason alone I would recommend the correct tool for the job.

A normal schrader dustcap is meant to offer a secondary seal in the event of a leaky insert; it has been my observation that metal dustcaps which include a core tool do not usually offer a good secondary seal; in fact they often offer a leak passage for air and dirt etc instead.

BTW the other prongs etc on the correct tool are meant for;

- cleaning up the external screw thread on a brass valve body
- opening valve inserts for tyre deflation
- removing sheared-off/failed inserts
- removing insert seal rings that might stay trapped in the valve body
- cleaning up the insert screw thread in the valve body

amongst other things.

cheers

[mercalia]

BTW the other prongs etc on the correct tool are meant for;

- cleaning up the external screw thread on a brass valve body
- opening valve inserts for tyre deflation
- removing sheared-off/failed inserts
- removing insert seal rings that might stay trapped in the valve body
- cleaning up the insert screw thread in the valve body

amongst other things.

cheers

have always wondered what they were for

"cleaning up the external screw thread on a brass valve body"
I thought was just use the valve as a place to keep the tool

[nomisp]

Hi, Am i wrong in thinking that if you have "slime" in your tyres then you should try and inflate them with the valve at the top of the wheel to prevent valves becomming blocked with the slime when putting air into the tyre and maybe causing the promblem that the original poster is experiencing. nomisp

[gregoryoftours]

Hi, Am i wrong in thinking that if you have "slime" in your tyres then you should try and inflate them with the valve at the top of the wheel to prevent valves becomming blocked with the slime when putting air into the tyre and maybe causing the promblem that the original poster is experiencing. nomisp

I would have thought that it would be the other way around - you'd have to pump with the valve at the bottom of the wheel otherwise your valve is inverted and a little slime will collect in it and get into your pump head too. There shouldn't be enough slime that when pooled at the bottom of the inner tube it would cause any problems for the valve at the 6 o'clock position, or if there is a fair amount maybe at the 5 or 7 o'clock position.

[townbikemark]

Cheers for the replies guys (rhymes...), I'm off to buy one of those tools in the third post first.

[townbikemark]

An update: - I bought both a valve core remover recommended by gaz in post 2 and the item in post 3 by Brucey for under a fiver. The valve core remover proved to be easier to use due to the limited room on a Brompton's wheels.

Job jobbed and I'm back on the road/path

[Sallykeyn]

This has just happened to me. After trying every possible solution suggested, including soaking the inflated tyre/ valve in hot water, I used a hair dryer on hot intermittently, jabbing and pulling the inside of the now completely munched up valve. Eventually, the thing just exploded, spreading green slime all over the kitchen ceiling! But, it's better than giving it to Halfords to sort, or punchering the tyre to deflate the inner tube. Good luck, slow and steady wins the day.

[Nicholas]

I think the slime/gunk stuff on a Brompton is a whole world of pain. I'd take a good quality tube (Schwalbe AV4) and tyre (again, Schwalbe) any day.