new U joint alpha one Gen II

williemon

Cadet
Joined
Apr 13, 2016
Messages
23
Im installing new u joints in an 06 alpha one gen II serial number OWxxxxxxx From what I see the sierra 18-6406 is a replacement for this GKN external clip perma lube style. I already have a set of precision 344 joints from an auto parts store and can have them installed and be on the water quickly. Using a micrometer, they seem to measure the same except for the trunnion (the shaft that the cap fits onto). The 344 measure .16 and the old merc u joint measures .17 This is for a V6 motor. Is there any issue using these 344 grease-able joints? Does the smaller size of the shaft under the cap cause a problem?
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,360
As long as your not mixing and matching the caps. Both appear to be using external rings

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71Z4UuYHb4L._SX425_.jpg
bottom is Sierra
 
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williemon

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Joined
Apr 13, 2016
Messages
23
Thanks for your thoughts. I was pretty much thinking the same thing since the caps measure the same, but the measurement of the shafts that the caps fit onto was my concern. Since the new ones I have are just slightly smaller than the original, .16 grease-able vs .17 non grease-able (but still drilled or hollow, not solid), should I refrain from using them? Would they be more prone to breakage?
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
71,130
Ayuh,.... Welcome Aboard,.... Ya can't put enough horsepower through an outdrive to break a new unworn u-joint,.....

Either of 'em,...
 

williemon

Cadet
Joined
Apr 13, 2016
Messages
23
Thanks guys!! I will work on it today and be back on the water soon. I will let you all know how the install went.
 
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