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Welding near fuel tank
skodaman - 5/6/08 at 09:55 PM

Got one of suspension bolts stuck on my Mondeo, tried all the usual stuff but it wont shift and the head is knackered. I reckon it's thread locking compound probably used when car was made. Only thing i think will now shift it is welding a socket to the bolt and using a long bar.The bolt goes into rear upright. If I disconnect the battery is it safe to tack a socket to the bolt with an arc welder?
Working on this car p's me off so much that instead of eventually using it's engine in the locost I might even use a bike engine


Mark G - 5/6/08 at 10:04 PM

If you're just tacking it on you should be ok. Be sure to take your time and not let the area get too hot. If you're concerned you could always try and make some kind of spark shield between the weld and tank.

[Edited on 5/6/08 by Mark G]

[Edited on 5/6/08 by Mark G]


eccsmk - 5/6/08 at 10:06 PM

itll be fine tack away
as said above just shield the tank with something


MkIndy7 - 5/6/08 at 10:07 PM

If the bolt heads still good, Loctite and no doubt other people now do a freezer type spray for un-doing stubborn bolts.

No dobt using the different thermal contraction of the metals, same as with the heating.. only much safer around objects like the Fuel tank

[Edited on 5/6/08 by MkIndy7]


jambojeef - 5/6/08 at 10:09 PM

I reckon you'd get away with it but if it really is that stuck I could see you shearing the bolt off in the HAZ of the weld.

So you've soaked in plus-gas and used an impact socket + breaker bar and all that type of stuff?

Is the head of the bolt totally mullered?


skodaman - 5/6/08 at 10:25 PM

Yeh the head is knackered. I welded a two foot piece of box section to a spanner and completely goosed what was left of it. Thing is I got the bolt out once with a socket and got it halfway back in. Both times it feels like the thread had stripped but it hadn't. Was incredibly hard to turn even wi a big torque wrench. Plus there are traces of what looks like dark red locking compound on threads.
It wasn't just the heat getting to the tank that worried me. Just thought there might be some chance of the electricity from the welder causing a fire.
Know what you mean about the likelihood of it snapping. Cos that's what happened with most of the bolts on the front suspension two years ago. Are all the bolts on modern Fords made of either glass or chocolate? Thought they had to be 8.8 or higher? Jeez even the old FIAT Pandas were better than this.


saigonij - 6/6/08 at 06:20 AM

what age is the mondeo, i thought they had plastic fuel tanks....

just a thought... welding, blob of hot metal hitting a plastic tank......


02GF74 - 6/6/08 at 10:34 AM

stupid question - this is your donor? so can you not remove the tank?

explonding petrol tanks is overrated I reckon, when I was much younger, I gound off the bolts holding a leaking MGB tank - they always went on the top as it was a water trap and nothing happened.

if you are worried, and I guess you should be as it ain't woth taking chances. Do it outside away from your thatched cottage, filling tank with CO2, make sure it is sealed - use insulation tape for the cap, cover with damp blanket have a sand/water/extenguisher handy and weld away.

O2 law's (TM) works on the princple that the more you are prepared for something to happen, the less likely it will.

incidentally when you were refitting it, ya should have run a tap through.

my money is on the bolt not coming out.

[Edited on 6/6/08 by 02GF74]


aerosam - 6/6/08 at 11:18 AM

how about these?

http://www.machinemart.co.uk/shop/product/details/5-piece-bolt-grip-set/path/socket-sets-sockets-tool-sets


skodaman - 6/6/08 at 01:04 PM

Used one of them grip sockets on my sump plug once and they're good but not up to this.
Yup tank is plastic. Think i'll do the job away from my thatched garage and with extinguisher nearby.


Mix - 6/6/08 at 04:10 PM

Hi

Sounds like the threads may have galled, (picked up and damaged each other). Weld a socket on, use lots of lubrication, and try to remove the bolt a bit at a time screwing it in and out. If you get it out you will at least need to restore the thread in the upright before replacing the bolt, (with a new one).

Regards Mick


jacko - 6/6/08 at 05:27 PM

REMOVE THE TANK
I had a MATE that was welding under a car the fuel come out a fuel pipe i lost my mate

Don't take RISKS with FUEL

[Edited on 6/6/08 by jacko]


rusty nuts - 6/6/08 at 06:22 PM

Remove the strut complete with the hub assemly ?