Round 3, FOAK: 1982 Kawie KZ550 C3 LTD Restoration Options - Page 13

 

Biker Dude wrote:


I wouldn't bother replacing Phillips head screws with socket head capscrews.
Just use an impact driver to remove them, it reliably breaks loose
corroded screws.  Where appropriate, I use anti-seize.  I don't use Loctite
for anti-corrosion reasons but I do use it where indicated in the manual or
where I think it is necessary.

http://dirtbike.off-road.com/dirtbike/data/articlestandard/dirtbike/232006/332676/tools17.jpg

http://www.bikernet.com/garage/loctitetech.asp

 

olsonm@tiny.invalid says...

http://dirtbike.off-road.com/dirtbike/data/articlestandard/dirtbike/232006/332676/tools17.jpg

Mark speaks truth :)

There's also thread SEALER.  It's a weak version of Locktite that just
keeps air, moisture and spooge out of the threads.  Good for non-
critical screws (whatever those are) or screws that won't vibrate out.  
Locktite does the same thing, but also prevents the screws from
loosening.  Loctite doesn't affect torqueing.  For more information than
you'd care about:

http://www.henkelna.com/us/content_data/138230_LT4985TLCapabilityGd.pdf

Lots of other information their web page too.  For a mechanical geek,
very interesting.  

Seize grease does affect correct torque values, so be careful!  

 



I don't use either one on screw threads.

I spray WD40 on the threads so the screw will turn in smoothly.

I never use a torque wrench on threads that I've lubricated in this
manner, I rely upon my calibrated wrist when tightening the bolt.

Several months (or years) later, when I loosen the WD40 lubricated
bolt, it takes the same amount of force as if I was loosening a
factory intalled bolt.

The bolt (or screw) comes loose with a *snapping* sound.

 

1949 Whizzer wrote:


Snapping sounds on undoing a fastener not Loctited are generally not good.
It points to contact face issues such as corrosion, galling, scarring or
localised weld points fracturing as the contact faces rotate as the
clamping force is removed. This interference twixt fastener and fastened,
coupled with the distortion of the threads pressure face and the metals
propensity to want to return to its original shape gives in part the
clamping pressure. This is good for internal assemblys, not so good for
external case covers where all we desire is the fasteners to provide
sufficient, uniform clamping pressure to allow a gasket or O ring to do its
job until we want to remove the cover.

An assembly paste, be it a grease type or Loctite type coats the thread
contact faces to minimise metal-metal contact and fill the voids to
minimise or indeed eliminate the possibility of outside agents entering the
voids[1], causing corrosion and swelling, leading to chewed heads when it
comes to undoing them.  

That 'snapping' sound is worthy of research. I haven't worded it
particularly well, but I hope I have managed to pique some curiosity in to
the method of operation of threaded fasteners.

The links provided by Mark, after Mark Olsens post provide some good reading
for the curious geek.


[1]Images of 'Mission Impossible' type micro-agents seeking out a means of
ingress to fastener voids and filling them with magic corrosion stuff.

 

Biker Dude wrote:


Get the nearest size bit to what remains of the head. Coat it lightly in
fine valve grinding paste and thump it in. The shock can help break the
corrosion and the grinding paste helps the bit grip the head.


Stainless steel fasteners with, in personal order of preference, aluminium
grease, copper grease or moly grease thinly smeared in to the threads works
for me in the land of road salt.