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Propeller Shaft Hardware

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Michael Oritt

Michael Oritt

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I'm installing the propeller shaft tomorrow and I wonder if there is any reason to replace the present fasteners with grade 8 hardware. FWIW I've never had any problem with present nuts and bolts and I know that high-strength hardware is not always the best choice due to its being more brittle.
 
If it ain’t broke …..don’t fix it .
 
I used AN aircraft bolts with self locking nuts on my driveshaft. I suspect that AN, MS, OR NAS bolts would all be good choices. Available in 1/16 increments at your local aircraft supply house.
 
Michael, how big of a prop do you have? :smile:

The bolts used with a OEM gearbox are special - instead of a hexagon head, the sides are round with one flat. Like a cheese head screw without the slot.
 
BobHaskell said:
Michael, how big of a prop do you have? :smile:

The bolts used with a OEM gearbox are special - instead of a hexagon head, the sides are round with one flat. Like a cheese head screw without the slot.
Click to expand...

And I use self-locking nuts with blue threadlocker (after all, belts are known to fail so you need suspenders).

Another issue (this may be the height of anal-retentiveness): Like with castellated nuts (suspension parts and on the front hub spindles), there is usually a gap between the nut--or, in this case the bolt head and its flange-- and a cotter key that would allow the nut/bolt to rotate ever-so-slightly and relieve some of the stretch tension on the nut/bolt. So, for the driveshaft fasteners (and castellated nuts), before torquing I back the bolt head back so that the edge of the flat is set against the yoke flange in the de-torquing direction, and wedge a flat screwdriver under the gap before torquing it so that the bolt cannot rotate and relieve the tension on the bolt.

It would be possible, working from memory, to drill the bolts and nuts so that safety wiring could be used. The principle is the same: wire the nuts/bolts in such a way they resist loosening:
 

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Bob_Spidell said:
And I use self-locking nuts with blue threadlocker (after all, belts are known to fail so you need suspenders).

Another issue (this may be the height of anal-retentiveness): Like with castellated nuts (suspension parts and on the front hub spindles), there is usually a gap between the nut--or, in this case the bolt head and its flange-- and a cotter key that would allow the nut/bolt to rotate ever-so-slightly and relieve some of the stretch tension on the nut/bolt. So, for the driveshaft fasteners (and castellated nuts), before torquing I back the bolt head back so that the edge of the flat is set against the yoke flange in the de-torquing direction, and wedge a flat screwdriver under the gap before torquing it so that the bolt cannot rotate and relieve the tension on the bolt.

It would be possible, working from memory, to drill the bolts and nuts so that safety wiring could be used. The principle is the same: wire the nuts/bolts in such a way they resist loosening:
Click to expand...
Perhaps I should have mentioned it, but I have a Toyota box and hence a non-standard drive shaft.
In any case I reassembled today with old hardware.
 
Old hardware installed yesterday and with car up in the air on jackstands nothing blew up when I put the car in gear and dropped the clutch.
 
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