If an old hob with brass taps you could take apart and clean and grease however new aluminum valves should not be re-greased as they tear when dry and get damaged so you are causing a danger by greasing
If you remove an old hob and strip down and service and repair and replace and still have a slight leak or another leak appears in the future and you have to remove again,you are in the area of the customer having an old appliance and you are carrying out uneconomical repairs, before you know it,the customer has spent a few hundred pounds and it and may require replacing anyway or you have to swollow the cost of the work you have done and just make money on the new instalation
If you have an all singing and dancing one that is £600 then
1. Yes it may be worth repair
2. It probably will not have a leak in the firstplace anyway
Yes the old moffat hobs and grills were good,nobody can dispute that and a bit of graghite greese on the taps of these may well do the trick,as said there is always the exception to the rule but if I have a leak other than the tap on the mofett ,I would scrap,hard nosed I am in the business of safety and cost effective repairs not sentiment
We are talking the new breed of hobs here,ie zanussi ect and still stand by my statement of just scrap them if they leak,for reasons above and if you try to repair them ,you will get your fingures burned,they belong the the throw away world
inho