dobbslc
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Just my 2 pennys worth
You doing this with the engine cold? Will it start? could try taking them out when its hot,no?
Post 22 ^^^
- Thread starter Jembo28
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Post 22 ^^^
Shedendman
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In addition to Shedendmans 'take two' of run the engine first also try tightening the bolts before attempting loosening them. M6 screws and a plastic lid ought to mean low torque. Likewise if they go 1/4 turn or so then stop, work it back and forth gently. If the bolt/s goes springy don't go any harder you reached the yield point.
Just a thought - what about one of those Sakertool portable welders. Or is it sacrilegious to even mention such a thing here... Would that produce less heat (ie with the plastic cover) and possibly be easier for a novice like me plus get the job done?
No, I work from home, so leaving it up on stands whilst the job is done is fine.
George A2Y
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The studs with heads would still be there, plus a small section of stud and plastic, the depth of the plastic. There would be a good bit more to grip than you have at the moment.
I see what you mean - the length of the stud that is currently inside the depth of the plastic cover. But there wouldn't be any "heads" left surely or the cover wouldn't come off?
hotponyshoes
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It doesn't matter what type of welding machine it is. It will either have enough power to weld the nut on, or it won't.
I'm guessing it's probably a 6mm bolt so pretty much any welder will do.
Lidl probably sell a welder with a budget mask and enough wire/rods to do the job from a household plug. They are cheap as chips and if you stick it on ebay with postage afterwards you'll get back what you paid anyway.
If you want to weld, see what the biggest size socket is you can fit over the existing bolt heads. Get some plain steel nuts to suit.
Drill out the center of the nut with a countersink bit so you have a Vee shaped hole to fill with weld.
Clean the top of the bolts with a wire brush in a drill/dremel/something.
Hold the nut on top with a pair of pliers and weld the nut on.
By the time you have done all of them the first should be cold enough to try undoing.
Welding nuts on helps in 2 ways,
First, it gives you something to turn (as you have already mutilated the existing hex)
Second, some of the heat from the welding will conduct down the shank of the bolt and into the thread.
If you get enough heat into the bolt it will expand. That expansion crushes the corrosion around the bolt. In your case it will crush it into the surrounding aluminium head as that is softer than the steel bolt.
Then (in theory) when the bolt cools back to normal size the bolt/corrosion/head bond should break free allowing you to extract the bolt.
In practice, that probably won't happen.
Firstly, you can only get to the head of the bolt to heat it so by the time the heat has conducted all the way down to the end of the thread the plastic cover will have melted.
2nd, the aluminium is going to be tightly bonded to the bolt and aluminium is a very good conductor of heat so will be drawing the heat out of the bolt.
3rd, if you manage (somehow) to get the thread of the bolt upto 400⁰c it's only going to expand by 0.015 of a mm.
That's not enough to crush 20 years worth of corrosion.
Another downside with welding a nut on is you'll exceed the heat treat tempreture in the welding area. If (and they might not be) they are high tensile bolts you've just lost the strength meaning they will probably snap at the bottom of the weld.
Not the end of the world but I'd just remove the heads and lift the rocker cover off if you want to save it.
Plus you then have the original bolt shank at full original strength, and then you have more chance of them getting out via easier methods.
Welding a nut on would not be high on my list of choices.
I'd start with a set of screw extractors and grind one of those down until it was a perfect fit into whatever is left of the hex drive. If they won't pull it out they'll either shear the head off or, they'll spin which will leave you a nice round hole to send a drill bit into.
Alternatively, study some pictures of a removed rocker cover.
Does it really matter if you melt it a bit?
If it's the usual type (plastic with a metal tube bonded in place) is there enough meat around the tube to drill a new hole and insert a bigger one if it gets ********?
Is there enough meat over the top of the holes to grind a flat to cover any metled areas with a big washer?
Could you plate over the top of it?
And so on..
Also, don't forget, they might not actually be corroded in. Unless you have had the car from new the there is the very real possibility that the previous owner had a rockercover weep and rather than replacing the gasket just cranked all the bolts up as tight as they would go..
This could mean the female thread is deformed and damaged and when you finally manage to get the bolt out it brings all of the female thread with it leaving you learning about the world of pain that is helicoils...
