Howard 350 petrol cock stuck on.

[rjy]

This is the screw-in type.The turning “knob” was missing when I bought it. I unscrewed the thing from the tank, wire gauze filter incorporated, can blow straight through from the output or input, the brass shaft of the valve has been a little graunched (by a pair of pliers by the look); I have unscrewed the hollow nut that retains the whatever gubbins unside, there’s a rubber “O” ring under it, removed.

Clamped the body in a vice, got the flat part of a Mole grip on the brass shaft, it would not move with reasonable force; warmed it up, put some paraffin and oil in there, warmed up until boiling, re-tried turning, no chance.

Any ideas? Dont want to put too much of a twist on it in case it shears.Don’t know why it’s stuck, sorrosion (brass/light alloy) I guess.

[charlie]

A photo or two of the tap might help us diagnose the problem.

[rjy]

Hi, it’a a bog standard petrol tap as in the example pictured from JAPG Mowers. The turning buttom has fallen off (not a problem, I can make one). The hollow nut around the spindle unscrews, there’s a rubber “O” ring under, nothing else to be seen. The die cast body is in one piece. The spindle will not turn. It is stuck open.

• This reply was modified 1 year, 3 months ago by rjy.
• This reply was modified 1 year, 3 months ago by rjy.

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[john-e-w]

with the output pipe facing up, try filling it with penetrating oil

John e-w

[davidbliss]

I have had some of those taps and were alloy not Die-cast metal that can be very difficult sometimes as with age and what metal mix its made from on that day or even hour so can get very bad internal corrosion and expands, had some new 1940s carbs still in there original greased packages just a myriad of cracks, warming the stork a few times might help just be carful as the die-cast melts at a low temperature, and have shifted some frozen parts from carbs by boiling them in a saucepan with ordinary washing powder as it dissolves the old varnish left from the petrol.some I have welded (more like soldering than welding) with some special low temp rods and some leaded solders will work, messing with the 100+ year old of unobtainable parts some times a needs must and worked to save the day. or I make patterns and get them cast and machine or machine from the solid so its fit and forget.

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[sidevalve5]

David,

Hugely impressed with the machining you can do. Have a mate who is very elderly who can do similar. Know it takes a massive amount of skill, experience and time to produce such items.

Grahame

[davidbliss]

As nobody tells me that can’t be done without certain machines, I just do it on clapped out old things some rescued from the scrap, spend hours making a press tool for a thing that would have cost pennies, but get satisfaction no one else have ever bothered, its often funny the crudest made tool can turn out a complicated to form the metal boys say impossible, then say would cost thousands just for the tooling, if my idea of a tool didn’t work it wouldn’t matter but has so far. It isn’t just machining I will have a go at tin work, and make parts by just welding, I had made a engine manifold, sent a photo to a friend in the States saying there you go casting by mig welder, well blow me they do just that continuous welding with a CNC mig water cooled, annoying thing I haven’t the knowledge of how to program. Door capping’s for a 1915 car, was told a very difficult part to make as had a slight curve, well D shape railing top bent to give a curve and a block of Elm wood, four G clamps, one hour to fold up four mark free.The cast exhaust manifolds metal was shot so bent pipe and a few drawn metal elbows, cut and lots of welding and finish inside is as good, no one would ever know they weren’t the originals and they haven’t warped. like the cast ones do.

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[rjy]

To return to the subject at hand. Repeated applications of home-made penetrating oil in all orifices, gas torch until sizzling then cooling, spindle in soft jaws, spanner on petrol cock body, turning…. “Click!”. The threads in the body need cleaning up, they’re stiff, the spindle threads seem to have suffered. Don’t know what the thread is, might be 1/16″ BSP (?). I’ve got some gauges somewhere, and some taps.

• This reply was modified 1 year, 3 months ago by rjy.

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[davidbliss]

They often keep to same BSP thread pitch for pipe fittings, however if you have a gauge it saves guessing. if its of US manufacture they use NPT thats only one thread per inch different, I get the odd motor cycle they often used cycle rate 26 tpi for there oil fittings thats not good into alloy being so fine. I often make my own taps and dies and a easy metal to machine then harden is EN24 works quite well as can go up a few thou without going up to next size. I recently was repairing a 1924 French car gearbox that was very poorly designed that allowed a non captive bearing to work partly off, as there is a French odd ball metric pitch I did that at a imperial 1/2”size to be equally awkward.

[sidevalve5]

If originality or you get the understandable satisfaction from doing a repair to the existing tap. Then you can carry on doing it with the care you have taken to date.

Personally I would replace it even it just to save the time and the trouble of fixing the old one. I am more interested in functionality that originality. Expect the thread into the tank would be BSP, it likely to be either 1/8” having a 0.383” diameter and 28 TPI. Or 1/4” with 0.518” diameter and 19 TPI. The fuel pipe is most probably 1/4” bore. Would fit a small in line filter too. There are loads of different petrol taps that would fit. Again personally would not fit an Ewarts cork one from choice. Find they often leak. But have replaced the cork with some O rings and that seems to offer a good seal.

[Author]

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