Is drilling out whats left, the only option to fix cooker burner?

[Ernesto]

I've been pleased with the first 3 years of Adria Twin ownership in that, the number of things breaking of failing has been very low. However I do think one of the weaknesses is the integrated sink and hob. No matter how careful you are, water gets from the sink onto the burners, and I now have a problem with the burner closest to the sink.

Its started to splutter with a very poor flame and once gas supply was ruled out as a cause, I had to disassemble the burner. First issue was the two small retaining bolts that hold the burner cap in place, were also rusted and the heads "fell" off at the first sight of a screw driver. At least this allowed access to the burner body, and looking into the bottom with a torch, it seems to have rust at its base, and possibly explains the poor flame.

In order to replace the burner body, I need to extract whats left of these two small threaded screw shanks - there's very little to get a hold of, so pliers aren't an option. Could any more engineering-savvy people than me recommend anything else please? Drilling will be tricky given the small size, but is that the only option ?

 

[The Coops]

Try an easy out stud extractor if that does not work find an engineering shop with a spark eroder but make sure the gas bottle if off the van and the system flushed through

 

[Orion]

Try an easy out stud extractor if that does not work find an engineering shop with a spark eroder but make sure the gas bottle if off the van and the system flushed through

As above, stud extractor - mini sets available from the usual online outlets - but also worth soaking beforehand in a decent penetrating oil, plus apply heat or even a freeze spray as applicable.

 

[ChrisL]

Does the aluminium bit that the screws are seized into not just pull off? It may be a tight fit but it looks exactly like the ones on my old hob which did just pull off, if so take it to an engineering shop, what I would do is build up the remains of the screw using a mig welder in short blobs, once the screws have been built up sufficiently use mole grips to turn the screw, the heat from welding will also have loosened the screws.

 

[Ernesto]

Thanks for the ideas ... ChrisL - thats a good point - the alloy burner is not threaded but I think the rust between the screw shank and burner body, is holding it too tight to move. But I will try some careful extra leverage first ...after that stud extractor seems best way to go ...

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[poppycamper]

I would file off what is left of screw head before trying to pull aluminium body.

 

[ChrisL]

Instead of mole grips they could also weld a nut to it and use that, have a look at the video below to get an idea.

 

[ChrisL]

I would file off what is left of screw head before trying to pull aluminium body.

I think the screws just hold the top plate on to stop the plate from jumping off whilst driving, I don't think they go all the way through the aluminium part.

 

[Stealaway]

Do you have room to drill it out bigger and go up a size screw. Maybe 3 or 4 mm

 

[pappajohn]

Try an easy out stud extractor if that does not work find an engineering shop with a spark eroder but make sure the gas bottle if off the van and the system flushed through

Going to have to drill it for an easy-out so just as easy to drill and tap a slightly larger hole .....and use stainless screws.
The body is cast alloy so will be a pig to drill without wandering off the screw remains.

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[xsparks]

Your biggest problem will be to stop the drill running off the steel and into the alloy.

 

[Oldrat]

I think the screws just hold the top plate on to stop the plate from jumping off whilst driving, I don't think they go all the way through the aluminium part.

Agree

Looks like my Dometic hob, and if so, the screws are self tappers and used just to hold the burner discs down, not to secure the ring to the hob

 

[tonyidle]

Drilling will only work if done with a pillar drill and a short, sharp, drill bit. My bet is a swift tack with a MiG to give you something to get hold of. The heat will help to free them.

 

[62272]

Personally I‘d file off the top so it is flat, and centre punch the broken screw centre, then drill VERY slowly with a sharp small drill piece and 3 in 1 oil dripped onto it. Then try and clean up the swaft with a fine tool.

Other techniques above may work, but if you're stuck.

 

[Ernesto]

Its correct that the screws are threaded at the base and only hold burner disc - they screw into studs, which are double ended (so to speak).

The top end of the stud holds the burner plate screw - the other end of the stud is threaded and secures the burner mechanism in place to the hob - this lower end of the stud is only visible from the underside of the hob.

The studs have a hex shaped outer, visible once the alloy burner is removed on the top of the hob, so if I can get the burner plate screws out, I can undo the studs and remove the burner itself

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[Ernesto]

Going to have to drill it for an easy-out so just as easy to drill and tap a slightly larger hole .....and use stainless screws.
The body is cast alloy so will be a pig to drill without wandering off the screw remains.

I agree...if I manage to get this off without damaging the alloy, I will have been very lucky I reckon

 

[donkey]

I don't think the top plate needs to be secured with screws/bolts and would work just as well placed back into position.

Geoff

 

[TheBig1]

A couple of heating/cooling cycles will definitely help free off the seized threads. File the tops flat and use a centre punch followed by a screw extractor. Done carefully will cause no damage

Strip it all down and de-rust in a warm pot of white vinegar. Re-assemble using new stainless screws

 

[pappajohn]

I really can't see heat having any useful effect
After all, the broken screws are millimeters away from a hot flame but the still seized.

 

[ChrisL]

I really can't see heat having any useful effect
After all, the broken screws are millimeters away from a hot flame but the still seized.

The heat from mig welding is significantly hotter than the heat from the burner, the different rates of expansion of the aluminium and the steel screws may help to free them off.

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[TheBig1]

Big difference from radiated indirect heat from a cooker ring and direct conducted heat. As above aluminium and steel expand at different rates when heated. The kicker though is that aluminium melts at a much lower temperature too if using the welder to spark onto the steel screw to give something to grab on

 

[TheBig1]

6x Broken Screw Extractor Remover Tool Speed Out Drill Bits Damaged Stripped UK | eBay

6PCS of Screw Extractor. ★Easy to Use: Set the drill to reverse OR counterclockwise and use a slow drill. Start the extraction by using the drill or polishing tip and drill down to create a clean hole.

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[matt34]

you did clean out the jet? unless the burner has rusted through should not be a problem.

 

[Ernesto]

you did clean out the jet? unless the burner has rusted through should not be a problem.

I think rust is preventing the gas supply properly opening up. If I can get the burner plate off, I may be able to clean it up.