Thread locking - what to use?

[Wil2k]

Hi all,

I'm About to refit the auxiliary housing (holding Pas & water pumps and AC compressor) in my Discover 2.

It looks like a thread lock compound was on the bolts holding the housing to the engine block. What can I safely / effectively use when refitting these bolts?

I've seen loctite mentioned a bit on here. Which one suits?

Cheers

Wil

[67hardtop]

Loktite 242 or 243. Its blue in colour and will lock ur bolts or nuts, but will still be able to be undone again without too much effort. Other types of loktite (red) can be almost impossible to get undone on smaller diameter bolts without breaking them. Hope this helps.

Cheers Rod

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[Wil2k]

Loktite 242 or 243. Its blue in colour and will lock ur bolts or nuts, but will still be able to be undone again without too much effort.

Awesome, thanks Rod. I have some of that kicking around. Wasn't too sure if it would be okay for a hot engine.

[Mercguy]

You can also use GMH thread sealing compound (repco) used for head bolts, or Permatex Indian head gasket cement (shellac compound) or the blue / purple locktite / equivalents. Parker make the purple stuff, can't remember what the number is, but the trick is to look on the label for 'frequent disassembly' because that means it can be re-used and will not sieze.

The GMH thread sealant was used on the bolts that went into the water jacket on holden 6 cyl and v8's and works equally as well. bit harder to undo but is watersealing as well.

The trick with threadlocker (blue loctite) is to not use too much on the thread. Also, the threads must be chased with a tap / die if removed before reapplying the compound. Some other compounds are 'self-healing' and work a 2nd or 3rd time.

Nut lock / studlock compounds can be more aggressive, and will yield at a higher tension, which is why there are advisories against using these compounds on threads smaller than 8mm.

The main issue is to make sure the threads are spotlessly clean and not to over apply the compound.

[ramblingboy42]

Loctite make thread locker that never hardens but will not allow a thread to come loose.

Blowed if I can remember which one it is.

If anyone ever gets an opportunity to attend a Loctite demo/seminar it is worth your time.

Most good tool/engineering shops will have their brochures as well.

[Blknight.aus]

generally the correct amount of loctite to use is a dollop the size of the minor diameter of the thread size of the bolt.

[mick88]

The CRC Brake and Clutch cleaner is a good product for cleaning up bolts and threads before assembly with thread lockers or sealers.


https://www.autobarn.com.au/crc-brak...sol-500gm-5089




The AC Delco product mentioned above is a good product, but you need the "deed" for the house with you when you go to get some. It ranges in price from $50 - $80 and will probably last you for the rest of your life, but works out costly if you just want to do a one off job.


HEAD STUD SEALANT GM 3835215 GENUINE HOLDEN BOLT GASKET SEALANT AC DELCO 250ML - AcDelco


Cheers, Mick.

[Mercguy]

The AC Delco product mentioned above is a good product, but you need the "deed" for the house with you when you go to get some. It ranges in price from $50 - $80 and will probably last you for the rest of your life, but works out costly if you just want to do a one off job.


HEAD STUD SEALANT GM 3835215 GENUINE HOLDEN BOLT GASKET SEALANT AC DELCO 250ML - AcDelco


Cheers, Mick.

LOL Mick. Not sure what I paid for it 25 years ago. Still have it. Still works as good as it did the first day I needed it. Keep in a cool dry place and all will be well with the world

[Busted Syncro]

G'day All,
The trick to removing bolts that have been put in with Loctite say 609 or Studlock is heat the bolt head to a dull red which soften the Loctite and then undo. Don't reuse the bolts again if you heat them.

I always keep a check list of the type of Loctite I use on my 2a bolts and nuts. That way you can be sure whether to heat or not.

If you don't know whether Loctite has been used on a bolt start undoing and if it starts to move then locks and you force it, you will strip the threads. Big job to fix!!!.
When the bolt locks simply heat to dull red and it will undo nicely.
Have a practice with a used bolt and nut and fix with 609 bearing lock and get the feel of how it moves then locks.

Chris

[Gerokent]

Two piece washers are very good. Can't think of the correct name for them now though.