Gas Hub and stiff Knob

[Exhausted]

If it safe to turn off the gas mains , then use WD40 to try to loosen a knob, The knob works but has suddenly gone stiff

Thanks

[Andrew Gabriel]

The grease has probably got too dry. WD40 will wash it off, but then there may not be enough grease to seal anymore. Depends on type of tap, but I would say this is only safe if you regrease with gas c*ck grease, which would require disassembly, cleaning (for which WD40 is useful), regreasing, and reassembly.

[Heliotrope Smith]

Not a good idea to use WD40 on a gas tap if it is the tapered type.

These rely on a coating of graphite grease to prevent gas escaping and WD40 can wash this away. Far better to dismantle, clean up and apply a fresh coating of grease. Just be careful not to lose any small springs etc that may come adrift when dismantling.

[John]

Would the experts suggest that an ordinary oil might work?

[Exhausted]

Many Thanks, Glad i asked, though i may need something special , Any recommendation's What about this stuff ?

[Exhausted]

Heliotrope, Not sure how to describe the tap. From a usage point of view the knob is pressed down the turned, although you can feel some sort of tacking as the tap is turned kind of an arch. If the tap is turned on and off a few times it loosens up (although not at must as the other taps)hence i just though it was dirt. There appear to be two screws either side of the spindle.

Does this help at all?

[Andrew Gabriel]

Dow Corning Molykote 1102 Gas Cock Grease.

You can probably buy it in a plumber's merchant, or failing that, BES certainly do it mail order, or do a search on Google for other suppliers. It comes in 50g tubes (and larger tins).

[NOSPAMnet]

I dunno..Stiff knobs,gone stiff,Cock grease ..What's this ng coming (oops) to Stuart

[Andy Wade]

That's the stuff:

[newshound]

This is on a cooker or something similar then? It won't be a taper c*ck type from your description, it probably has O-ring seals. WD 40 or another penetrating oil might free it up. I don't know what the seal material will be, but I'd guess nitrile or viton, in which case the mineral oil in WD40 or similar shouldn't do any harm. But, the seals may be damaged already. Procede with caution; a healthy nose isn't a bad leak detector.

[Exhausted]

NewsHound, are you saying this is possible not as Andrew and Hetro Typehave said?

Yes this is from a cooker hob. I have tried to draw in ASCII (sorry) what i believe it looks like (Below) There is a sprung spindle (shown as : ), which requires to be pushed down before turning. The top of the tap (shown as |) which the spindle goes though is held on by two screws shown by *

: : : : |: :| _*_|: :|_*_ : :

If this is the type of tap which required gas c*ck grease, where is it applied, just on the shaft that goes though the top of the tap, and if so could i do this with out undoing the screws by applying crease then pushing the spindle down a few times before tuning The spindle needs to be pushed down approx 3mm

Thanks

[Exhausted]

I've attached a link to image shack which has a picture of the gas tap.

tap in question is the one at the top of the picture. A few points which have come to mind are

1. When the knob is pressed down its feels slow, kind of link there is a thick layer of oil, where as the other knows feel like there is nothing stopping the movement
2. when the knob isrotated its never smooth , feels like there is something like a grain of sand in the valve. Also the last bit is stiffer

when the knob is rotated back and forth a fe time is becomes loser, although still feels rough , almost like there a grain of sand with no lubricant.

hope this helps.

ANy ideas of the way forward ?

[Exhausted]

just turned the gas back on , and there is faint smell of gas coming from the tap, when i put leak testing solution(washing up liquid) on the tap i see a few small bubbles.

I have turned the gas supply to the cooker off

What now ? what type of tap is this ?

Any advice

[Exhausted]

Is there grease I can get today (Bank Holiday) and use as a temporary measure

I have silicon grease in the house

[Andrew Gabriel]

This would be consistant with either the existing sealing grease having gone hard (might have been washed out by food oils/grease over the years) or something like an O-ring mangling.

Did you do anythning to it when the gas was off (I've lost the flow of this thread somewhat)?

I think your choices are

1) take it apart, clean it up, reseal it (new grease, O-rings, whatever), reassemble, and test, or 2) buy a new tap, fit and test, or 3) buy a new cooker.

[Exhausted]

When the gas was off i simply turned the tap on and off a few times to see if i could loosen it (also pushing the tap down and pulling it up to try to move the lumps), and it worked.

I also cleaned around the top of the tap with paper towel and water, in case any dirt there had affected the tap. It was after the paper towel and water that i noticed the gas.

I am planning on calling a gas fitter tomorrow, but in the mean time can i use any other grease(silicone maybe) as a temporary measure so the hob can be used ?

I was not planning on taking the tap apart , but rather putting the grease around the tap and pushing up and down, whilst turning on and off to help the grease into the body of the tap

[Heliotrope Smith]

Don,t rely on any kind of temporary measures when dealing with gas. If it is leaking and you are unable to make a "proper" fix then your only corse of action is to turn off the supply and leave it to the gas fitter.

[Exhausted]

That's what i have done, gave up looking at the costs of new hobs plus the cost my fitter will charge vs the risk is just not worth it

I may even have a new oven as well. Do I need to change the hob and oven together or can they be done individually ?

[dennis]

They are usually unrelated. However you will probably get a package deal for less than the individual items and its cheaper for one visit from the fitter than two.

>

[newshound]

As someone said before, it might be stiff grease in a bearing "outside" the gas circuit in which case WD40 might get you working. Or it might be a chewed O ring exposed to gas in which case there is a risk that fiddling around might cause a leak. Personally I can't see anything wrong with trying to get it to work, as long as you stop and isolate it for an expert to fix if you discover it is leaking.

Unless you have no sense of smell at all you will definitely know if you develop a leak large enough to be potentially dangerous from something as accessible as a cooker tap. In fact you will probably hear it.