Bravo transom assembly leaking

Boat is a '99 Chaparral Sig 27 with a 7.4 MPI Bravo 3.

Today was the first day of break in on the new motor after a 2 months of boat woes getting this project completed. The new motor ran great. Other than I had the coolant reservoir too full, the reman'd motor is real strong runner. I replaced the y-pipe o-ring before installing the engine just because I had time.

I noticed some water in the bilge while on the lake. I broke my trusty flashlight and was expecting something different. I saw consistent water drips falling off the trim pump hoses. Naturally I suspected the bellows had developed a crack and was water was coming through my gimbal bearing. I turned the wheel in both directions which had no effect on the flow whatsoever.

On closer inspection, the water seems to originate ABOVE the gimbal bearing/shaft opening where the steering lever goes through the transom. There was water on the lever opening, but not on the lever itself. Because of the way the transon assy is built, the water flows around the bearing. I have not removed the drive to see if the bellows is also leaking, but there's no water shooting above the u-joint shaft.

I looked at the service manual for guidance, but I have questions. I think I know the answers, but...

1) If the the steering lever opening is indeed the source, is there a bushing or seal to keep water out?

2) If there is a steering lever shaft seal, do I have to remove the transom assembly to make the repair or can I remove the bell housing and go that route?

3) If the steering lever shaft opening does not have a seal of it's own, can I assume the the transom seal is what is actually leaking?

4) We're still unusually wet n nasty with Spring weather in the Pacific Northwest so the 2010 boating season is going to be pretty short. If the transon assy seal/o-ring is the culprit, could I use a sealant around the transon assy as a short term fix AND OR determine if it's leaking.

I just had the engine out of the boat so I'm reluctant to pull it again, but having water coming into the boat...well...just ain't right!

Any thoughts are greatly appreciated.
Kevin

Re: Bravo transom assembly leaking

Howdy,

We're still unusually wet n nasty with Spring weather in the Pacific Northwest

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It's Junuary right?
Or is it summer yet? I can't tell.....

On closer inspection, the water seems to originate ABOVE the gimbal bearing/shaft opening where the steering lever goes through the transom. There was water on the lever opening, but not on the lever itself.

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That sounds suspiciously close to where the speedo-pitot tube is..... That's where my leak was.

If the the steering lever opening is indeed the source, is there a bushing or seal to keep water out?

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I don't remember there being any sort of "seal" there. And I don't think the water level is up that high is it?

If the steering lever shaft opening does not have a seal of it's own, can I assume the the transom seal is what is actually leaking?

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The transom seal *could* be leaking but it should have been leaking all along...... unless you have some rot "issues" going on in the transom.

You could probably run a bead of silicone around the transom on the outside and see if that stops the water. That would tell you if it's the transom seal.

If you've already had your engine out, it'll be easier the next time!!



Regards,


Rick

Re: Bravo transom assembly leaking

Though I am still sorting out a host of other issues with my most current rebuild (engine been in and out a few times over the last 5 years lol) this is the first time since I have owned this boat (SR 26' CC MCM 7.4 B1) that it is not leaking sea water into the bilge, and the problems that were fixed were interesting, but fairly simple.

One was the replacement of the Y pipe as you claim to have done (did you seal her up real good or just rely on the o-ring seal?) New shift cable boot and correct clamps (the u-joint bellows was done during the last attempt to get the engine in so it must still be good lol), but the unusual ones were that all the nuts on the transom assy were needing a few turns to be tight, the two upper middle bolts were never installed (looks like from when it was new) and the lower Al transom bolts though appearing to be ok were rotted through and little more than decoration.

I never did find that I was able to view where the water was getting in from, but the above fixes have allowed a dry bilge for the first time in nearly 10 years so they may be some good things for you to check out and confirm to be OK.

Hope that helps, and good luck as I literally "feel your pain"

Re: Bravo transom assembly leaking

After using the correct search words, found a bunch of info.

And to make matters worse, I finally fell victim to Lake Tapps too...dinged the props just prior to hauling it out. Went from 26' to 3' in about a second. Thankfully I was only at idle and the skeg was untouched. $300 screw up, but just pissed me off! Bad timing.

I'll check the pitot tube as that would be an easier/cheaper fix. Maybe I damaged it when R/R'd motor, but the speedometer is fairly accurate and consistent with GPS SOG. I suspect my problem is the gimbal ring swivel pin thingy. I'll do some reading this afternoon and take a look tonight.

Thanks for the info. I'll update when I know more for sure.

Re: Bravo transom assembly leaking

Y-pipe o-ring? Didn't rely on the ring itself. I used black RTV (my go to for just about everything) as an adhesive rather then the 3M stuff. When I bought the boat, I learned real quick how much a leaking y-pipe oring is...$1000.

11 year old boat means it's time to do some non-routine maintenance.

Re: Bravo transom assembly leaking

collawash said:

Y-pipe o-ring? Didn't rely on the ring itself. I used black RTV (my go to for just about everything) as an adhesive rather then the 3M stuff. When I bought the boat, I learned real quick how much a leaking y-pipe oring is...$1000.

11 year old boat means it's time to do some non-routine maintenance.

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That is one mighty expensive o-ring once things go bad isnt it

I guess a tube or cartridge of RTV can sometimes be worth its weight in gold.

Just be sure to double check that the transom assembly is all tightened up, and any through bolts are still there and sealed as well as this is the most likely unnoticed or last place mine was taking on water.

Oh and sorry to hear about your prop

Re: Bravo transom assembly leaking

collawash said:

And to make matters worse, I finally fell victim to Lake Tapps too...dinged the props just prior to hauling it out. Went from 26' to 3' in about a second. Thankfully I was only at idle and the skeg was untouched. $300 screw up, but just pissed me off! Bad timing.

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Lake Tapps is full right now! where were you when you dinged the props? at the ramp?

Re: Bravo transom assembly leaking

Your symptoms look right for a swivel shaft leak, happens to all Bravo outdrives after a while. The shaft is not stainless, so when corrosion sets the seal gets destroyed. I think at design time it was assumed that the top of the assembly never goes under water, but unfortunately it does.

I have changed mine after 17 years by removing the gimbal housing when the engine was out for rebuilt. You can replace the shaft, seal, and bushings without removing the engine. There is a Merc approved way, where you cut two holes in the upper gimbal housing, which will be tapped and pluged later. Then you use the holes to access the upper swivel shaft nuts. The success depends on the level of the upper shaft corrosion, I doubt it would have worked on mine. The other way (suggested by an aftermarket company) requires cutting an opening in the back face of the swivel shaft housing, which is later covered by a provided stainless plate. It might work even for a well corroded shaft, next time I see a leak I will go that way. The company also sells a stainless replacement shaft which is claimed to last longer than the original. I think they sell it on Ebay, just make a search for "Mercruiser swivel shaft".

Re: Bravo transom assembly leaking

Yes Rick, I is a dumbarse...

I was in the cove just to the E of the launch on the N side by the park. There were some bass fisherman working the submerged spits earlier in the day. I was idling over them watching the depth and all the fish! I went from about 25' to about 2'-3' in a second. Grabbed the throttle to get it into neutral while trimming up the drive, but wasn't fast enough. Just 2 little bumps tore up the outside edges of the props. Just a $320 fix plus tax. With as much money I've spent on the boat lately, what'$ a few more?

This is my first outdrive repair ever! I don;t believe the gimbal ring will have hardly any wear but won't know fer sure until I get it off. Trying to gather all the tools and parts QUICKLY cuz want to be on the Pacific by no later than the 4th! Going with the SS swivel shaft (Hill on sale $159) and SS u-bolt since shaft rust probably caused the seal to fail. I'd like to install zerks too. I have about 1/4" to 3/8" of so called gimbal ring/steer slop which doesn't seem all that bad after reading about 4" to 8" of slop in other threads. I retorqued the u-bolt but didn't make any noticeable difference in the slop. Even if the little slop were removed, I highly doubt the seal will now miraculously keep the water out? Replacing the u-joint and shift cable bellows as they are original. Bearing is only 2 season old and feels brand new.

I'm going with the JR method, not the Frankenstein. Taping 1/4" holes seems far easier than 1 1/8" holes.

Do I really need a u joint bellows expander? Is it that much easier with the tool?

Just how difficult is it to change out the bushings? Will a socket work? I can get a bushing tool for the lower and side pin bushings for $48. Haven't found one for the upper. Ideas?

Sierra, Merc, GLM bellows...any real difference except the price?

It all seems rather daunting at the moment, but if I can replace an big block engine by myself, I should be able to do this. Right? Any other suggestions?

Re: Bravo transom assembly leaking

I haven't done my bellows yet but DonS says the OEM bellows is far better than the after market ones. (he's replaced a few of them)

Mine stays inside during winter and I think it will last a LONG time more than a few years so the additional cost of an OEM one is not all that more.

I was in the cove just to the E of the launch on the N side by the park. There were some bass fisherman working the submerged spits earlier in the day. I was idling over them watching the depth and all the fish! I went from about 25' to about 2'-3' in a second.

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Yeah....it IS shallow in there!! I haven't been that un-lucky yet!!