Bravo 3 yoke seal and bearing fail.-gctid804344

[Rick_Shaddock]

Hi,

We have a 2000 Bayliner 2455 with Bravo 3. We recently rebuilt the top end of the 5.7 EFI. In dry dock we removed the leg and as per Mercruiser repair advise cut a hole at the top of the leg to access the steering pin to replace with stainless Seacore. We took the boat out on a 5 hour trip with excellent performance throughout the trip. The next day as I was about to take it on another trip I found in checking fluids the leg oil reservoir was empty. Pulled the boat and back to the shop! We found the yoke seal and bearing to have failed. Brand new yoke seal and this was replaced in October 2014 according to my recoeds. It seems to be a recurring issue. My Mercruiser certified mechanic says he's only ran across this a few times and suggested putting a shower kit on the notoriously hot running Bravo 3's. Does this sound like a viable solution or could there be an underlying problem?

Any help with this appreciated,

Rick


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[builderdude]

Did these mechanics service the drive during the engine/gimbal repairs? An empty gear lube reservoir should have triggered the alarm long before the reservoir had emptied. Did the alarm sound? Sounds like there was an insufficient amount of gear lube in the drive and the alarm wasn't functioning causing the bearing and seal damage. Did these mechanics do all this work on your boat?

[Rick_Shaddock]

Yes, all work was done correctly as far as I know. I was there for most of the tear down and reassembly as I was working on bottom coat, Trilux on the stern drive as it was completely apart for access. The reason for working on the drive was that the steering pin was leaking so as the photo shows we replaced with a Sea-core stainless pin prompting a significant reseal of the upper leg at the same time. Alignment was good and no rot was observed in the leg.

I should mention leg oil was apparently in the bilge but the bearing was clearly failed. I caught the low oil before any further damage but heard no alarms probably due to the leg oil not being fully drained.

[Ruffryder]

White caulking around the transom shield, wondering who did that? Is it leaking?

Whale tale on a Bravo 3 inch: ?

Yup leg alarm should have worked, so the gimbal bearing has failed or the yoke bearing? is it rusty?

If so, leaking drive bellows damaged everything possibly. ..

[fishaman]

The yoke seal failure is often caused by the groove in the yoke shaft, so make sure that either you get a new yoke, or the seal is offset a bit so that the lip is away from the groove.

Empty reservoir on the first trip after the repair could be caused by some air leaving the upper of the drive, normal if does not happen after refill.

And of course the alarm should have been blasting long before the reservoir went dry, check its operation by shorting two wires at the reservoir when engine is running.

[Rick_Shaddock]

A previous owner had done the caulking and whale tail. I replaced the caulking to separate the Trilux from the Interlux CSC Micron paint. The top end motor is new and is running perfectly so thought the extra torque could have been putting extra heat into the the whole process. I'm wondering if the shower kit will help the heating or if there is an underlying issue?

[MidnightSun]

I have had 2 yoke seals go on my previous Avanti bravo 2 which as your mechanics says is not common. I am 99% sure this was due to poor alignment issues I had which also lead to coupling failure over time. Drive showers IMHO are not required on your setup, they are more for high performance high speed boats. Have the alignment verified by someone who knows what they are doing which means they know to read grease marks. Just aligning until the shaft slides easily in and out and calling it a day is not going to do it.

[Rick_Shaddock]

I will pass that on to the mechanic. We've rebuilt so much on the mechanics so far we are way over budget so really trying to get this new issue solved. The Bravo 3 is designed so I'm sceptical of an after market solution like a shower kit.

[Ruffryder]

Shield gap should have been a bit wider 1"~1.5" at least,

Outdrive pressure test is in order,

Put a jumper wire on the gear lube reservoir low level limit switch , see if it will go off

[Rick_Shaddock]

I might add that the mechanic said the alignment was good. Certainly, I want to get this figured out rather than adding a shower and having a failure at sea. Makes for an unnerving boating experience!

[Rick_Shaddock]

The cap on the stern drive at the steering pin access? I think this is the Mercruiser stainless cap kit for this or at least the recommended kit? The hole is actually a fair bit smaller than the cap. My top of the head guess is that it's 21/2" x 3". I would like to see a pressure test. Of course if it's overheating than that will likely not result in a reliable conclusion. Will have them test the reservoir alarm as well.


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[builderdude]

It could have been as fishaman said, an air pocket within the drive after a recent service is common, itll pull lube from the reservoir back into the drive to replace the burped air. Test the reservoirs float switch (that's what triggers the alarm) Clearly you pulled most of the gear lube from the reservoir and didn't have the alarm sound so that needs to be fixed. Make repairs to the bearing, seal, and input shaft then pressure/vacuum test the drive before it's installed again.

[Ruffryder]

Yup access for the upper SQ shaft...looks to be the JR marine cover kit.

App 2.5" x 3.5

[Rick_Shaddock]

That's it! In this photo there appears to be extra drilling on the side tho? Not the case with my repair.

I just went down to the dry storage to check the reservoir to see if it has the wiring to the alarm. I have to get this tested and fixed. Someone pointed out a float in the reservoir so while it's empty I will check to see if it is moving. The wiring looks at a glance to be properly attached.

I spoke to the shipwright at dry storage and he is adamant that my mechanic knows how to align everything having assisted him over 40 times with leg installations. It was just as concerning to the mechanic that the bearing had failed but he and another mechanic ascertained that a shower kit would be a good idea and it may have just been time for a new bearing. The bearing may have been heat damaged from the previous owner or the added torque from an engine rebuild. Have to remember the engine is at peak performance as prior to the rebuild it took quite some time to get to plane. Now it just jumps out of the water in less than 50 to 60 feet. Big difference! Thank you for sharing this photo. I know now the mech did a good job there.

[builderdude]

The Bravo is a stoutly made drive it can easily handle whatever HP your 5.7 can throw at it. The float switch in the reservoir may be held up with some goo in the bottom of the reservoir. If you can move it freely up/down then it could have just simply failed (stuck open) When the ignition key is turned to the run possition you should hear the alarm sounding, this is because your engine isn't running thus producing no oil pressure. Temporarily unplug the oil pressure switch and tape off the wire to silence the alarm. Press down on the float switch inside the reservoir, you should hear the alarm again, if not the switch may be bad or the wiring connections corroded or similar.

PS when I purchased my boat the alarm wires were cut, seems the PO didn't want to trace down the faulty switch. In my case all three were bad inch: