Failing u-joints-gctid815767

[Guest]

I have a Bravo III hooked to a 7.4 Mercruiser in a 2859

My problem is the u-joints keep going out on it.

I don't operate with the drive in the up position, the spline and shaft are lined up using the line up tool.

I've had this problem for about 4 yrs now and I'm tired of pulling drive about every 100 hrs of operation and replacing u-joints.

Does anyone have a hint of what my problem could be???

Thanks

Skeeter

[Castaway]

What are your symptoms? How do you know they're failing?

[builderdude]

"Castaway" post=815773 wrote:
What are your symptoms? How do you know they're failing?

Good question, are you getting howling during turns?

[Guest]

When I turn over about 15-20' they make a klunking sound.

When I pull the drive they don't look to bad but after installing new ones there is no noise from them.

[2850Bounty]

A Marine Stern Drive universal shaft bearing cross should not be wearing out prematurely. Something is wrong, and let's see if we can find it!

First off..... these must articulate or the needled bearings will "point load". This means that the bearing cap must turn back/forth on the trunion surface.

The idea is that the articulation will keep the needle bearings constantly changing positions on the trunion surface.

If they are not constantly changing positions, they will point load and will wear prematurely.

These images may help you understand what the components are and perhaps help explain how they function.


Attached files

[builderdude]

Pretty easy to bend the drive yoke replacing the cross there, ask me how I know inch:

Could be a possible cause for them wearing prematurely.