Locktite For Exhaust System?

[Autotech]

They probably are metric.

There are special nuts available which combine self locking with anti-seize properties. They are made of steel, but are copper coated. Never seen one come loose, or become so seized it couldn't be removed.

These nuts are standard fare on BMWs. If your local NAPA store does not have a source for them, take a sample nut to your closest BMW dealer (if you have one) and match it up.

The only possible complication is that your threads may be very fine - for some reason the Japanese tend to use finer than standard thread for everything, which can make finding hardware a real PITA.


Gregg

[fivestring]

Mike, there are also nuts that are oblong in shape. These go on the bolt tightly because of the oblong shape. These operate like lock nuts without the plastic middle that would melt on an exhaust system. I have used these oblong nuts with success.

[LazyJ_Arabians]

If you ever had a big cam engine with tube headers you learned real quick how to use stainless steel safety wire. They make washers that fit around the flats of the fastener that makes safety wiring a simple fix nowdays.

Safety Wiring

[CJDave]

[img]/forums/images/icons/smile.gif[/img] Yep.....the spring tension does add to the security as much as the bite probably does in some setups. [img]/forums/images/icons/tongue.gif[/img]

[bgott]

Go to the dealer (a Toyota dealer might be a better bet) and buy new nuts. Check the studs closely, they are probably eroded and need replaced, too. Standard brass nuts on those metric threads might work as a one time shot. Lock washers aren't any good on an exhaust, they lose there temper from the heat. It's a sucky job but fix it right the first time and you won't have to worry about it again. New nuts and studs.

[MikePA]

I stopped by the dealer this morning and the parts guy let me look at the parts schematic.

1. The stud was not listed as a replacement part.
2. The only thing holding the pipe to the header was a nut. A later model showed a nut and a spring combo.
3. The dealer didn't have any nuts in stock, so he ordered 4 of them for me.

[bgott]

You want to stack a few flat washers and space the nut before the eroded part of the stud.The spring and nut combo works a lot better. It lets the engine move on the mounts without trying to twist the exaust pipe. However, that set up takes a longer stud. If it continues to give you problems after changing the nuts you might want to get a junkyard manifold with the longer studs and swap it over. Get the junkyard to cut the pipe so you have the whole set up. Manifold work can really suck.

[MikePA]

Attached is a picture of the nut (I got four of them at $2.75 each!).

What kind of nut is this and is there a special 'installation' procedure, given the split?

[fivestring]

Mike, to me, it looks like a nut to use with a cotter pin; line the slots up with the hole in the bolt and push a cotter pin thru.

[Inspector507]

Could they have been squeezed in at the split on top? That would give a lot more resistance to backing off.