Breaking valve off inner tube because pump won't let go!

Whrrr

Active Member
I have an Airworx Control Track pump and for all the time I've owned and used it, I've had problems removing the pump attachment from the presta valves.

I remove the cap, unscrew the valve and tap it to free it up, letting a small amount of pressure out as I do so. I attach the end of the pump hose, lift the lever clamp and then pump to the required pressure. It's removing the attachment after this that is the problem. It is incredibly difficult to pull off. I release the lever, do my best to hold the base of the valve with the little round nut with my left hand and pull the attachment from the valve with my right. After several weeks, the valve just tears off the inner tube because I cannot hold the base of the valve down and it requires an enormous effort to get it off. It proved impossible to remove this morning and despite checking the lever was released and doing my best to hold the base to the rim, it tore off again.

I cannot find anyone having similar issues on this forum. Is it possible I have a faulty attachment (oo er). Or is my removal technique suspect (oo er).

Any advice would be most welcome!
 

ASC1951

Guru
Location
Yorkshire
I don't understand how the valve can tear loose if the locking nut is done up - on all my wheels, that holds the valve completely firm. As to the pump sticking, do you have the correct size of rubber grommet in the pump head? Is it obstructed in any way? It might be worth trying a new grommet.

[The usual problem is people bending or damaging the valve while pumping the tube up, which I find is easily avoided by placing the nose of the pump on something solid with the valve above the pump and the wheel resting on the pump body. Doesn't apply with a track pump, of course.]
 
OP
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Whrrr

Active Member
Surely the locking nut only protects the valve when pushing on it. It can't stop the valve from being pulled. If you tighten the locking nut too much, this also will tear the valve from the tube.

I'm not sure about the rubber grommet - it's as it came from the manufacturer and has always been the same. Are different sizes available? The hose attachment has two holes. One for presta and one for shrader. I tried pumping it up using a presta/shrader adaptor and then attaching it via the shrader hole instead, but it just couldn't keep a good seal with the higher pressure.
 

ASC1951

Guru
Location
Yorkshire
Whrrr said:
Surely the locking nut only protects the valve when pushing on it. It can't stop the valve from being pulled. If you tighten the locking nut too much, this also will tear the valve from the tube.
The locknut is there to for two reasons: to keep the valve in place when you are pumping the tube up; and to stop the tube moving relative to the rim when you are riding and therefore putting strain on the join. For the first it doesn't need to be tight, for the second it does. You can of course get valves with unthreaded stems, so it is debatable whether you actually need a locknut, but personally I find them easier to inflate.

Without watching you inflate the tube it is a bit difficult to see whether it is something that you are doing, or a fault with the pump. Track pumps are pretty simple objects, so if yours is all correctly assembled it may well be your technique.

My method with a new tube is to get it up to 10psi or so without the locknut on, so that I can push the tube about and be sure that it is bedding into the outer correctly; then I put the locknut on and take up most of the thread while I get the tube fully up to pressure; finally I do the locknut up finger tight. When I'm topping up (which is always with a track pump) I leave the locknut tight and only handle the valve head.

All I can say is that I have never ripped a valve out of a tube in 40 years of cycling.

[If you haven't had any problems with other pumps, it might be worth taking it to bits and checking that the locking assembly is working correctly. IIRC the lever has a cammed surface and maybe something has lodged in there or in the grommet. But if you have the locknut up snug, you're not going to damage your tube even if you have to wrestle the two apart.]
 
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Whrrr

Active Member
Everything you say makes perfect sense. It just seems very difficult to get the attachment to let go of the valve, despite pulling it directly away from the rim with no lateral movement. It's as if the lever has not been released.

I've ordered a new attachment (different design) which I hope will improve matters. Thanks for the advice.
 

delstron

Active Member
Most heads can be adjusted for 'tightness' by screwing the outer sleeve in or out a bit. This usually deforms the rubber seal slightly to improve the seal. If its too tight, this would give the problem you describe so try slackening it off half a turn?
 

ASC1951

Guru
Location
Yorkshire
delstron said:
Most heads can be adjusted for 'tightness' by screwing the outer sleeve in or out a bit.
I really should have remembered that, when my track pump can. :biggrin:

That said, from the online photos the Airworx seems to have no adjustment.
 

dodgy

Legendary Member
Location
Wirral
Here is your solution, it's what I've been doing for many years.

Smear vaseline on your valve threads, this creates a better seal and allows the the pump head to be removed easily. Alternatively, get a good dollop of spit on your fingers and wipe it on the threads before pumping :biggrin:

Let me know when you find this works, because it will :biggrin:
 
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Whrrr

Active Member
Problem solved - I've fitted a new pump attachment and all is well. It goes on and off very easily, so I can only assume the Airworx one wasn't right somehow (I could find no adjustment on it).

Thanks to everyone who gave advice - much appreciated.
 

youngoldbloke

The older I get, the faster I used to be ...
I have found when faced with similar problem that easing the head away with both thumbs works - rotate wheel so valve is at 12 oclock allowing hands to push down either side of tyre. Push and ease head off valve from tyre side rather than pull.
 
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