PDA

View Full Version : broken prop shaft


hadzinak
05-17-2011, 03:43 PM
My prop shaft broke for the second time on the couple side just after the coupler....

DooSPX
05-17-2011, 03:47 PM
OUCH!! How in the world did you break a shaft? Hit something with some force?

muskingumriverdocks
05-17-2011, 04:27 PM
Sounds like it's misaligned. Happened to my '74 SS once when the rubber came out of one motor mount.

hadzinak
05-17-2011, 04:47 PM
misalignement...

DooSPX
05-17-2011, 04:56 PM
ouch!!!! I'm sure your strut bushing needs replacing and possibly even the strut it self?

ahhudgins
05-17-2011, 05:36 PM
misalignement...

Who's doing the alignment? When I purchased my last used MC it had a bent strut. When I disconnected the coupling at the transmission, the shaft was a good 1/4 inch out of alignment due to the previous owner driving around with a bent strut. How far out of alignment do you have to be in order to actually snap a shaft in half????:confused:

G-Star
05-17-2011, 05:43 PM
Who's doing the alignment? When I purchased my last used MC it had a bent strut. When I disconnected the coupling at the transmission, the shaft was a good 1/4 inch out of alignment due to the previous owner driving around with a bent strut. How far out of alignment do you have to be in order to actually snap a shaft in half????:confused:

If the shaft is out of alignment, it will create cyclical loading bending forces on the shaft as the shaft rotates. The more times the shaft rotates, the more load cycles the shaft goes through. Each loading cycle causes metal fatigue, and eventually a crack will develop and the shaft will fail.

I would think there would be some noticeable vibrations to go along with the misalignment long before the shaft failed, though.

hadzinak
05-18-2011, 12:31 AM
it felt as if I was in an old truck as far as the vibrations go... The shaft snapped when I put it in reverse to park the boat. As far as I can see the bushing was good and the strut didn't have any visible problem. The lower broken part was rotating smoothly through the bushing/strut... Does a machine exist that can align the shaft or is it done manually ?

JLeuck64
05-18-2011, 01:46 AM
That's a nice pry bar ya got there!

Seriously, don't throw away the old prop shaft. There is NOTHING better to use when trying to push around the engine and trans when aligning them to the prop shaft... nothing ( ;

G-Star
05-18-2011, 12:06 PM
it felt as if I was in an old truck as far as the vibrations go... The shaft snapped when I put it in reverse to park the boat. As far as I can see the bushing was good and the strut didn't have any visible problem. The lower broken part was rotating smoothly through the bushing/strut... Does a machine exist that can align the shaft or is it done manually ?

You are ze machine. ;)

There are a couple good threads that describe the procedure... this one should help:
http://www.mastercraft.com/teamtalk/showthread.php?t=8806&highlight=alignment+procedure

Also, there's a good document that describes the whole procedure. I managed to find and attach it.