Captive Nuts

[helen&tony]

Hi
Not the captive audience of us Bongo Nuts on the forum, but Mazda's own brand of the crabbiest captive nuts in the motor Trade....every time you come across one, even after soaking 2 or 3 times a day over a period of a couple of days, and tweaking the bolt slightly, you are left with a bolt which has to be cut off, and the resulting nut and piece of slit bolt rattling around in the chassis like a skeleton playing tennis in a bikkie tin (polite version )...
Latest one is the front tow eye bolt on the chassis bottom....got one removed, and the other side let go gggggrrrrr Tony was not amused ...Now the question...is there a cavity fixing I can get to hold a nut in place, inserted from the "front", as there's no access in the chassis...and I have to fit my recently acquired bottom chin guard....over here it's like the wilderness for normally obtainable parts and gadgets at a decent ironmongers!
Thanks in anticipation
Cheers
Helen

[dave_aber]

Sounds like a job for rivnuts.

But, you have to drill an accurate hole, and if there's a bit of knackered bolt still in the nut the hole won't be in the right place.

You could always cut around the offending nut, and weld in a washer with a nut welded on the back.

[helen&tony]

Hi
Dave...
Now there's a thought....I had been toying with the idea of getting a bit of studding welded in, but that's a doozie of an idea a nut on a washer...I did look at Rivnuts, but I don't think they do large ones?...I might get the lads to make a hole large enough to get the old nut out with a bit of wire....before they weld it up with "nut -on- washer"
TOP MARKS!!!!!!!!! I'll pop in on Wednesday!
Cheers
Helen

[dave_aber]

I've used the "nut-welded-on-a-plate-with-a-hole-in-it" technique before. I just invented (in my head) the "nut-welded-on-a-repair-washer" technique just now.

You get rivnuts up to about M12 I think, but as the hole size increases, so does the thread size. So you can't drill out a knackered M6 nut and fit a 'repair' M6 rivnut in the big hole, it would be a M12 rivnut, and thus a big bolt, so a big bolt through whatever you are bolting on etc.

Interestingly, you can get rivnut studs too as I have just discovered by the witchcraft that is google.

The "bolt-welded-on-a-repair-washer" technique is also available!

[helen&tony]

Hi Dave
I bet that Nut-washer will go down a storm here...just about everyone welds!...in fact, our friend in the village made his own arc welder...it's like an industrial transformer, and takes 3 to lift it!...I'm just going to take it to the garage, though, as our friend will probably weld some HUGE apparatus together
Cheers
Helen

[MountainGoat]

So it seems that you are on your way to getting the problem sorted Helen. That's a relief, when I first saw the headline I thought that you were refering to the guy that you married. Pew! us Tony's live to fight another day.

Tony

[helen&tony]

Hi Tony...
Yup....Tony (him Indoors ) was struggling with that bolt...we had an extending socket wrench about 2 foot long and a hide mallet down at the village inspection pit....NO WAY was it going to move...thought of firing up the compressor and getting the impact gun on it, but that thing is an absolute master for shearing bolts!....Never get that trouble with the old Land Rovers...their captive nuts are impossible to snap off, even on an old Series 2A ...just disjointed shoulders....we had a stuck nut on a wheel one day, and it took an 8 foot pipe and 3/4 drive bar, but it shifted...I think Mazda stuff is a bit weebly in comparison
Cheers
Helen

[Rhinoman]

You can also get shouldered nuts which can avoid having to weld a plate on a 'normal' nut. I used to keep all my old rounded off nuts for jobs like these but about 20 years ago I bought a Metrinch socket set and haven't rounded off a nut since.

[helen&tony]

Hi
That's also an idea...we have a box of spares, so I'll get hunting for a shoulder-nut....
Cheers
Helen

[winchman]

Just for future
I have one of these at home
http://www.amazon.co.uk/dp/B000WTJPLO/r ... B000WTJPLO
It was £12 and a trip to the local nut and bolt shop filled a bag of inserts for £5, it been really handy.
Welded nut and washer is possibly the best for now though as the bits are readily available

[dave_aber]

I've just bought one of them too, for fitting threaded inserts into awning brackets. I'm not set up for welding stainless, and fitting an awning to the brackets with loose nuts needs arms about 15' long.

[helen&tony]

Hi
I saw those Rivnut setters the other day, and thought the "Set" nut might be a bit puny, but 8 mm is a fair diameter bolt...I may look again at the bolt size...being that the chassis is whacked full of waxoyl, and I topped up last summer, I reckon there's a fire risk with welding!....
Cheers
Helen

[dave_aber]

It can be a dilemma - do you fill the chassis with waxoyl, and then dare not weld it, or leave it dry and ensure that you'll need to weld it!

I have in the past connected a second CO2 bottle to the chassis and flooded the area to suppress any fires. Bit dodgy, but it worked!

[helen&tony]

Hi
Dave....'tis indeed a dilemna ...I have a very small fingernail size hole in the chassis behind the front outrigger passenger side (front jacking point)...started at the flange that joins the outrigger to the chassis, where flexion separates the flange, and water gets in....I have just plugged it , after killing the corrosion...It gets no bigger, and is thoroughly sealed....BUT....try to weld it, and it WILL go up in smoke. Sometimes, I agree with an old friend (sadly deceased), who used to say a mechanical joint is often better than a weld!..A bolted flange is a better fix, but you need a stouter metal frame....I must have 2 gallons of wax injected everywhere in the bongo....it'sa nightmare crawling underneath...you come out tarred and feathered!
Another highly under-rated sealant is asphaltic bitumen...we did the Jag in that....BUT....very dodgy heating bitumen in an open vat
Cheers
Helen