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Join Date: May 2008
Location: Grapevine, TX
Posts: 465
Quote:
Originally Posted by RWebb View Post
No, b/c safety wire doesn't prevent loosening - it stops the fastener from bouncing around on the track (or bing sucked into a turbofan).

Once the CV bolts loosen, the faces of the joint/hub will no longer transfer torque. Instead torque will be transferred (briefly!) thru the bolts in shear.

The bolts will then be cut in half, and a large mechanical flail will trash your trans. & motor.
The intent of safety wire is indeed to keep the bolts from loosening/backing out.

per SAE specification AS567K

Paragraph 2.2.1 Safety Wire
Safety wiring is the securing together of two or more parts with a wire. The wire shall be installed so that any tendency for
a part to loosen will cause an additional tightening of the safety wire. Safety wire is not a means of obtaining or
maintaining torque, but a safety device used to prevent disengagement of the part. See Figure 1 for standard
configurations and terms.

So by definition, safety wire should prevent the fastener from turning in the loosening direction. The general public and likely most automotive hobbyists probably haven't had much exposure or training on the correct application and process for safety wire installation, so there are probably a lot of instances where the safety wiring has been done incorrectly, it is of course much better controlled in the aviation industry, but even so I've still seen instances where its execution was questionable.
Old 10-02-2019, 11:14 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #41 (permalink)
Topocalma
 
Join Date: Jun 2017
Location: Frankfurt Germany
Posts: 85
Quote:
Originally Posted by Solamar View Post
AND between the boot flange and CV joint. So four gaskets per axle shaft, eight needed total for a complete re-boot.

(true at least for the 100mm SC axle shafts)
Is this the case for all models? My 1977 Turbo seems to only have two gaskets per axle shafts, there are none between the boot flange and CV joint (10mm bolts). This is at least per the PET.

Also, my 1977 came without moon plates, not sure if this is the PO or factory. From the PET I cannot tell whether the Turbo should have them or not. I read the threads on CV joints and it seems consesus that the moon plates mainly provide a softer surface for the schnorr washers to dig in. Now the boot flange on my turbo seems to be made of brass and has a 'rough' surface as well. So no added value in a moon plate. Second thought is also: what good to have the schnorr washer dig in on one side (moon plate or CV joint flange) when this benefit ist not given on the bolt head - it would simple slip on this side...?
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1973 2,4T gemini blue
1977 3.0 Turbo slate grey
Old 10-09-2019, 01:13 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #42 (permalink)
Racer
 
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Join Date: Oct 2010
Location: San Martin, CA
Posts: 3,809
Quote:
Originally Posted by 76FJ55 View Post
The intent of safety wire is indeed to keep the bolts from loosening/backing out.

per SAE specification AS567K

Paragraph 2.2.1 Safety Wire
Safety wiring is the securing together of two or more parts with a wire. The wire shall be installed so that any tendency for
a part to loosen will cause an additional tightening of the safety wire. Safety wire is not a means of obtaining or
maintaining torque, but a safety device used to prevent disengagement of the part. See Figure 1 for standard
configurations and terms.

So by definition, safety wire should prevent the fastener from turning in the loosening direction. The general public and likely most automotive hobbyists probably haven't had much exposure or training on the correct application and process for safety wire installation, so there are probably a lot of instances where the safety wiring has been done incorrectly, it is of course much better controlled in the aviation industry, but even so I've still seen instances where its execution was questionable.
All safety wire does is prevent the bolt from loosening enough to fall out. Safety wire does NOTHING to help maintain torque. So what @RWebb says is absolutely correct.
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Old 10-09-2019, 08:38 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #43 (permalink)
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