Need Help with U-Joint Replacement

[graves_7]

I have a Volvo Penta SX-M 1.79 and I believe I have a U-joint going bad. I notice a faint knocking noise when the motor is trimmed all the way up and when the steering is turned all the way to port. I bought the boat last year (my first boat) and didn't now that I shouldn't be starting the engine trimmed up until researching this noise. Since I purchased it, I have always started the engine trimmed up for a couple minutes each launch.

​I feel confident that I can replace the U-joints following the manual but have a couple of questions.

​1. If I caused the issue starting the engine with the outdrive trimmed up will the Gimble bearing need to be replaced too (the gimble bearing and u-joint bellow was replace 3 years ago)?
​2. If I remove the outdrive and the everything appears to be ok with the u-joints and gimble bearing is there anything I need to replace like O-rings, gaskets, etc. before reinstalling the outdrive (I've purchased the alignment tool already).
​3. If the U-Joint is bad...is this all the parts needed to repair it? https://www.amazon.com/Sierra-Inter...e=UTF8&qid=1495989366&sr=8-1&keywords=3850812


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[Jammer864]

I doubt the gimblle bearing will need to be replaced. When you install the drive dont put any grease on the two o-rings on the input shaft. Do grease the input shaft splines with some moly grease. Also grease the bellows where it will mate up with the drive when you reinstall it (this seals out water at that joint). Finally, there is no need to spend 40 bucks each for U-joints. I just bought 2 at the auto parts store for 16 bucks apiece. and Yes, there are no other parts you need.

 

[graves_7]

I doubt the gimblle bearing will need to be replaced. When you install the drive dont put any grease on the two o-rings on the input shaft. Do grease the input shaft splines with some moly grease. Also grease the bellows where it will mate up with the drive when you reinstall it (this seals out water at that joint). Finally, there is no need to spend 40 bucks each for U-joints. I just bought 2 at the auto parts store for 16 bucks apiece. and Yes, there are no other parts you need.

​Thanks Jammer864.

 

[Jeepster04]

When you install the drive dont put any grease on the two o-rings on the input shaft.

Can you explain why?

 

[graves_7]

Can you explain why?

Jeepster04,

I was just going through the manual and this is what it says:

"Lightly lubricate the two driveshaft O-rings with Motor Oil. Grease
in the O-ring grooves can hydraulically lock the O-rings and cause
difficulty starting the driveshaft into the gimbal bearing.
"

 

[bruceb58]

I notice a faint knocking noise when the motor is trimmed all the way up and when the steering is turned all the way to port

That is pretty normal and its something you NEVER want to be doing. I never run my drive all the way up.

If your u-joints sound normal when the drive is down or just slightly trimmed up and you can turn the drive from side to side without noise, you don't need to change them.

 

[graves_7]

That is pretty normal and its something you NEVER want to be doing. I never run my drive all the way up.

If your u-joints sound normal when the drive is down or just slightly trimmed up and you can turn the drive from side to side without noise, you don't need to change them.

Thanks for the feedback. Right now the only time I really notice it is when trimmed all the way up (which I will NEVER do again) and it's only faint then. I am going to hold off on doing anything unless it seems to get worse. I will probably remove the drive and check things out before I winterize it this year.

 

[bruceb58]

I think you are fine.