Seized Header Nut - Help?

[Arvin_a]

I wish that I was asking for help with a 240z, but unfortunately I don't have one yet. Since a lot of you seem to have experience working with all kinds of problems on cars (namely aged and exposed ones), I thought I'd give it a shot here. I have a sentra, but nuts are nuts, right?

It seems that the dealership impact-wrenched the 14mm header nuts extra hard when they replaced it last year.

I'm tring to put on an aftermarket header, but I'm having a crazy-hard time getting the nuts off. I sprayed them with PB blaster anti-seize and let them soak for a few hours. Came back with and they didn't bulge. SoI got a blow torch and heated them for a while so they'd expand - nothing. Now three of them are pretty badly stripped and rounded off.

anyone have any ideas on how to get these stubborn nuts off?

[Carl Beck]

tell me what a "blow torch" is...

by "stripped" do you mean the nut turns, but does not move along the threads of the stud?

Carl B.

[Arvin_a]

tell me what a "blow torch" is...

by "stripped" do you mean the nut turns, but does not move along the threads of the stud?

Carl B.

Well, I went to home depot and got bottle of MAPP gas + the nozzle extension. I let the nut sit under the flame but not enough to get red-hot.

By stripped, I mean the nut isn't exactly hexagonal as the vertices have been deformed by the wrench. So the wrench moves, but the nut doesnt.

[zbane]

crazy idea here, but if the edges have been rounded off by the wrench, how about using a ratchet and breaker bar? I might think that if there are still six decent flat edges, and you were able to grasp all six together, you might be able to get around not having 6 defined corners ...
Of course I could be completely off base here, but it may be worth trying...

[Arvin_a]

crazy idea here, but if the edges have been rounded off by the wrench, how about using a ratchet and breaker bar? I might think that if there are still six decent flat edges, and you were able to grasp all six together, you might be able to get around not having 6 defined corners ...
Of course I could be completely off base here, but it may be worth trying...

Ah, good idea david. I tried a snug fitting ratchet & socket and it's still seized so hard that it just turns after enough force

[e_racer1999]

nutcracker? only thing i can think of.

[Carl Beck]

OK - - - you have a couple of options.....

1 - go to the Kano Lab's site and order a couple of can's of Kroil-Oil... wait for it to arrive. Then apply it to the threads of the stud and let it work it's way into the interface between the threads on the nut and the threads on the stud. At this point it might take two or three or four days... so you soak it down every day and let it set.

Kano Laboratories

Then - grab the nut with a firm grip applied by a good set of vice-grips - and smack the vice-grips a solid swift blow with a brass hammer. Do not apply heavy torque gradually by pulling on the vice-grips by hand - you risk twisting the stud off. Dynamic torque will usually break the nut loose. If you can't swing a brass hammer - hold the vice grips with one hand - and smack you hand with the other hand..

2. Second option - go rent or borrow a an oxy/acetylene torch. Heat the nut to a glowing red color - grab it with vice grips - and it'll break free and unscrew. Heat the "nut" not the stud... If you can not get a pair of vice-grips on the nut - you can usually get a box-end wrench to work on a red hot nut - because it expands and even if it's rounded off a bit - you'll still be able to get enough grip ...

You can buy a portable gas welding set at Harbor Freight - for $259.00, or sometimes Home Depot has Victor portable sets for just a little more.. This is a great addition to any garage...



Using "TIME" and Kroil - I've broken nuts/bolts loose that most people including me - would have thought to be impossible, without twisting the studs/bolts off. It's amazing what that stuff will do if you give it enough time and keep the parts wet down.

It's good to have a can of both AeroKroil and SiliKroil (spray can) on hand in the shop. It isn't cheap, but a can lasts a long time...

good luck'
Carl

[Arvin_a]

Thanks a lot, you guys have been more than helpful! Let me try this out and see if it works.

Carl, is this bernzomatic torch enough to get the nut red-hot?

[Carl Beck]

Steel turns orange/red hot at about 1800 degrees F...

An oxy/acet torch put's out about 6000 degrees F

MAPP gas - burned in ambient air is about 3000 degrees F (almost twice that if feed with oxygen)
Propane burned in ambient air is about 2400 degrees as I recall...

The flame temperature is only one aspect of heating that nut. The concentration and penetration rates are just as important.

If you hold an oxy/acet torch on that nut - in a few seconds the nut will start to turn orange/red hot.. So fast that the heat will not have the time to be soaked away by the stud, which is screwed into an aluminum head..

If you use that MAAP or Propane Torch - burning ambient air - held there long enough it will heat that nut to orange/red - but it will take so long that it will also heat the stud and start to melt the aluminum head. With the stud and head as heat sinks... you'll likely run out of gas before you see a steel nut glow red hot...

So - no - the Benzomatic won't do the job (not even close). It will sometimes work on lesser frozen nuts that simply require the application of some heat ... but not usually on rusted/frozen exhaust manifold nuts... nor header pipe nuts..

FWIW,
Carl B.

[Carl Beck]

Oh.. by the way... In my opinion one of the best and most useful "luxury" tools you can have in the garage is a portable gas welding set. Home Depot has fairly good one's for $279.00 (Lincoln Electric brand)... Harbor Freight has one for $259.00.

To me "luxury" tools are the one's that you buy after you have a solid basic set of hand tools. They are the one's that it's mostly a luxury to own, not a necessity. Things like a dedicated buffing motor/wheel, an aluminum floor jack, a good parts washing station, a bead blasting cabinet and a huge compressor etc etc.

You can gas weld just about anything on a car with that set-up, it will cut steel about 1/4" thick easily and it's a great help in breaking rusted nuts/bolts loose. Need to bend some metal? Build an engine dolly?... fix things that are metal and broken?

You won't use it every day - but it sure is great to have it when you need it.

FWIW,
Carl B.

[Arvin_a]

Gotcha, Carl. Thanks for all the great help!

[moonpup]

Hi Arvin, PM sent.

[xray]

Two thoughts:

1) "Header replaced last year" and rusted/seized nuts and bolts don't seem to go together unless you're in a real humid environment. Seems more plausible the nuts got cross-threaded by the impact wrench and mechanic who may not have been paying attention.... If that turns out to be the case, you may have to have the manifold studs cut to remove the header, then each stud manually extracted, followed by (maybe) retapping the stud hole...

2) If they are truly rust-seized, I would affirm the above-mentioned techniques. After soaking with penetrant (Kroil or PB Blaster) consider tightening the nut slightly (1/4 or so turn), then loosen. Once it begins to loosen, tighten it up a little, then loosen it some more. Use this "two steps forward, one step back" approach to slowly work the nut off. The shearing force of the friction produces some serious heat and can snap off the bolt if you're not careful. Brute force is not your friend, finesse and patience are....

Good luck,
Steve

[Arvin_a]

Hey all, sorry to resurrect a long-dead thread, but I just wanted to thank yall for all the help. I got a can of kroil and a set of craftsman bolt-out sockets for rounded nut heads. They worked perfectly together! I installed the aftermarket header and it sounds great.

here are the casualties: