Bravo 3 trim cylinder leak

[gapple12]

So as I’m working on my boat this past weekend, I noticed a small puddle under the outdrive. Further investigation I found it’s leaking from starboard trim cylinder where the shaft enters the cylinder (pic attached). I would say it dripped about a tablespoon all day on the ground. I’ve researched a little and everyone says it’s a easy job doing the break down and replacing the seals. True or should I just replace the whole cylinder? I’m seeing them up around $300 a side but the rebuild kit is around $20.

im not sure I’m finding the right parts, are all mercury bravo 3 drives the same?

 

[alldodge]

Yes, easy enough to just rebuild. Will need to either make or buy a pin type spanner wrench to remove end. Look for seal kit 25-87400A2

 

[gapple12]

Yes, easy enough to just rebuild. Will need to either make or buy a pin type spanner wrench to remove end. Look for seal kit 25-87400A2

OK, thank you. Do I need a serial number off my out drive to verify that is the right kit or are all Bravo 3 the same rebuild kit? I just read a thread where a guy left the anode on the end and used channel locks to twist the end cap off instead of buying the special tool. Sounds like a good idea as long as i dont mess up the anode. Also, since this is a hydraulic set up, is it better to leave it in place then disconnecting all the lines during the rebuild?

 

[alldodge]

A Bravo is a Bravo, and the transom assemblies are all the same. The bravo upper is the same for a 1,2 or 3, the lower is only thin that changes.

Yours is new enough that we don't need to look at the first gen bravo, but even those use the same seals. You can try to use the anode and see if it will work, my only thought is if the screws snap (doubt it, but anything is possible.

If you took a piece of steel and drill a hole in it a bit larger then the shaft on the cylinder, and drill close to the end. Then take a hacksaw and make the hole a U. Now measure the holes and drill two smaller holes in the steel. Find drill dits that will fit in backwards into the screw holes. Place the steel on the cap and insert the drill bits thru the steel and into the screw holes.

I use drill bits instead of screws because they are hardened

 

[gapple12]

A Bravo is a Bravo, and the transom assemblies are all the same. The bravo upper is the same for a 1,2 or 3, the lower is only thin that changes.

Yours is new enough that we don't need to look at the first gen bravo, but even those use the same seals. You can try to use the anode and see if it will work, my only thought is if the screws snap (doubt it, but anything is possible.

If you took a piece of steel and drill a hole in it a bit larger then the shaft on the cylinder, and drill close to the end. Then take a hacksaw and make the hole a U. Now measure the holes and drill two smaller holes in the steel. Find drill dits that will fit in backwards into the screw holes. Place the steel on the cap and insert the drill bits thru the steel and into the screw holes.

I use drill bits instead of screws because they are hardened

That is a great idea !!

On these trim cylinders, when you disconnect the 2 lines to it, will all the fluid drain out and do you need to bleed the lines after you reinstall the trim cylinder ?

 

[alldodge]

Some will come out but not all. You could get a jump when putting back together by moving the piston to the bottom of the cylinder, then fill part way with transmission fluid, and then install cap.

You could, but could also just run the cylinder up down several times and it will self bleed, just watch that the reservoir doesn't go dry. Once you no longer see bubbles in the tank after going full up then down, you should be good

 

[gapple12]

Some will come out but not all. You could get a jump when putting back together by moving the piston to the bottom of the cylinder, then fill part way with transmission fluid, and then install cap.

You could, but could also just run the cylinder up down several times and it will self bleed, just watch that the reservoir doesn't go dry. Once you no longer see bubbles in the tank after going full up then down, you should be good

Great, thank you for your help

 

[211libwtfo]

Glad I followed very informative

 

[gapple12]

Got the rebuild kit done today, wasn’t bad at all, but I need to get some fluid to top off reservoir before I run it up and down. A lot came out and I forgot to fill the cylinder before I reassembled it. What fluid do I use ?

 

[alldodge]

Use 10W30 motor oil

 

[211libwtfo]

Really? And I would’ve put tranny fluid in. Huh one more reason I love this place

 

[alldodge]

Yep, 10W40 can also be used but I would only use it in hot areas

 

[gapple12]

Is that what I pour into the reservoir? Motor oil, really ?

 

[alldodge]

Is that what I pour into the reservoir? Motor oil, really ?

Yes

 

[gapple12]

Ok, much cheaper then buying the trim fluid. Since I didn’t fill the cylinder when I reassembled it, just running it up and down until it fills will be ok ? I guess I just don’t let the reservoir go to low ?

 

[Bondo]

Since I didn’t fill the cylinder when I reassembled it, just running it up and down until it fills will be ok ? I guess I just don’t let the reservoir go to low ?

Ayuh,...... Exactly,...... it's a self-purgin' system,....

 

[gapple12]

Great, thanks again to everyone for your help, love these forums

 

[alldodge]

Yes and yes

 

[gapple12]

Well, happy to report the job is done and not leaking. Easy fix and I didn't need the special tool. :joyous: