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Bravo 1 prop shaft bearing failure

V

Villain lll

Member
We just got back from Lake Mead this last weekend. Water level is way down but very careful to not hit any obstacles. Prop is perfect.
Got back to camp and lowered outdrive to drain the last day, knowing the issues with quagga mussels.
First thing I noticed was gear oil coming from the back of the prop besides the water draining from the water intake holes.
I wiggled the prop and there was at least a 1/4" flex in the rear bearing.
I think fortunately it happened just as we were heading back in and felt a strange vibration and limped back in around 35 mph for 2-3 miles.
My alarm never went off due to low oil level and when draining out of the water back at camp, the outdrive oil was still pretty thick, void of metal debris, and flowing.
Today I just pulled off the lower unit and need to get the bearing carrier ring tool to start pulling it apart. Any ideas of who rents these specialty tools? I hate to buy for hopefully a one time use.
I'm new to this forum but not to forums in general and searched for a similar problem but nothing here.
Anyone else have a similar issue? I can't imagine why this failed unless a lack of lubrication or debris in the oil from another failure? I never ran the outdrive short of oil and change it out annually.
Before I complete the repair, I will inspect the upper unit for issues but any insight from those out there as to why it failed?
I will replace all bearings and seals and have my "11" manual for guidance.
Thanks.
 
I haven't seen any responses on this but I'm now thinking of just changing out both front and rear prop shaft bearings, only if the inspection looks good.

Maybe a crazy question but if I do that, do I need to re-shim, knowing I won't pull the vertical shaft?

Thanks for any insight.
 
Last edited:
We'll, I decided to buy the bearing carrier keeper ring tool and start to explore. In the meantime, I had drained the outdrive of water and oil and refilled with oil to keep any corrosion issues down.

I've got plenty of pullers and hope the next steps are relatively simple. A couple of You Tube videos to help with expectations. Never spent much time in salt and usually pull my boat out of the water each day when on the lake.

A little surprised I haven't seen anyone chime in on their past experiences with the same issue? Maybe a very rare occurrence?
 
Well,
I got my bearing carrier nut removal tool the other day and pulled it apart.

I had to use a puller with heat to remove the bearing carrier. What a challenge to remove.

After pulling it apart, I found the vertical shaft nut on the bottom of the shaft had come loose and stripped off the shaft. This allowed for enough movement to destroy the bearings, races, but fortunately, it looks like the gears and bearing carrier look good.

You can see the nut is knurled over.


image.jpg

The backside of the same nut.
image.jpg

The complete assembly, with gears that look okay. Time to order the lower unit replacement kit.
Any suggestions of a good source?

image.jpg
 
We'll
I found an old Service Bulletin, 92-3 that discusses an issue with the pinion nut coming loose.

"A. BRAVO LOWER GEAR HOUSING PINION NUT Models
All Bravo One / Bravo Two Drives
Changes
The pinion nut has been changed from an elastic stop nut to a non locking type nut, The new nut requires the use of type “A” (271) loctite.
Problem
There have been a few cases in the field that the pinion nut threads would strip out at torque value or just before torque value was reached when the nut was reused.
Parts Required
(1) pinion nut 11-20739 (.750-16) 1 1/8 diameter.
Repair
When rebuilding a gear case assembly replace the pinion nut with a new type nut (11-20739) and use loctite “A” (271) on the threads of the nut before installing. This nut requires the same torque value as the old nut,(120-125 lb.ft.)(163-170 N.m). "

Might be the reason mine came apart.

Next step is to order all the lower unit bearing, seals, and races. Upper unit looks good.

Haven't seen any suggestions of a good source to obtain? I guess I'll start digging online to find what I need. Still have buy the backlash measuring tool too.
 
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