Bravo 3, Advice Required.

[JamesTT]

Has anyone experience of wear in the outer section of a Bravo 3 transom assembly?

The boat is 5 years old, done 350 hours, is out of the water for 7 months each year stored dry and has been serviced and inspected in accordance with Mercruiser schedules.

Some pictures attached, a hole has now been cut in the outer casing to gain access to the tiller/ steering pin connection and investigate play in the leg and a water leak.

Just visible through the hole is a raised ring of the casting where the top of the vertical pin/bolt seats that then joins to the tiller as it protrudes through the transom, the casting is worn and rough preventing a proper seal, the drive has dropped, the bushes on the lower section were missing upon lifting the boat causing the excessive play and the leak.

The boat has completed 18 hours this season since March and a full service of engine and leg over winter including an investigation and fix of play that i reported in the steering, apparently this is a common Bravo 3 issue and was cured by drilling the side of the casing (hence the grommet visible to the right hand side of the casing) allowing access with tools to tighten the u-bolts on the tiller/pin.

I am advised that a complete transom assembly is now required and that the engine requires to be lifted out to fit the inner and outer new parts.

Any ideas as to what has caused this wear, has anyone experieced/seen it before, any advice greatly appreciated?

 

[spannerman]

It doesn't look too promising I'm afraid, I have rebuilt at least 15 of these transom shields for just this fault, including doing the boat I just bought!
Usually the seal in the under side of the shield where the steering pin goes in leaks or even falls out allowing seawater in which then corrodes the bushing and top surface where the steering arm sits.
I have come up with a mod which has never let me down if you catch it early enough.
I fit two seals instead of one with proper stainless springs in to apply tension around the pivot pin ( the original is a nasty hard plastic thing) and I fit them the wrong way round with the lips facing outwards which is wrong according to the manual but the correct way in relation to all other rotating shafts that are under water. I drill and tap a hole through to the pivot pin lower bush and fit a grease nipple on the outside of the shield so I can lube it like the early Merc shields had.I also fit an O ring around the pivot pin between the top of the gimbal frame and the outer face of the seal as this keeps the lips protected from stuff that grows on drives and keeps the outer lips pressed in against the pivot pin, it works well as there is only slow partial movement and not rotation as with a normal shaft.
I get the pivot pin machined and a stainless sleeve pressed on so its the correct diameter again so now you have a stainless surface passing through two seals with a lube point, and none of them have ever come back, as its now better than when it left the factory.
Unfortunately you have to remove the engine and drive and shield as when you strip it down you will see that the pivot pin and steering arm are the first two components that you assemble in the whole assembly from crank pulley to prop nut!
What is critical is that there is enough of the original metal where the seal sits otherwise there is nothing for it to sit in, the corrosion on top of the lower bush isn't too much of a problem as there is a stainless washer to take the load between the steering arm and shield, I replace the bush and washers as a matter of course.
Hope this helps, if yours is too far gone maybe someone has a good used one for sale from a repower.

 

[JamesTT]

Thanks Spannerman, got your reply and a couple of other very well informed and accurate replies by PM that confirm that the issue is a weak point on Bravo 3's.

I have approved the work to replace the transom assembly today, can't waste any more time out of the water.

Your comments with regard to the mod are noted, i will discus this with the mechanic.