drive unit u-joint rust?
 

hi gang,
pulled the drive unit off my bravo three yesterday to replace the shift cable boot and noticed the u-joint assembly has surface rust on it. is this normal? the oil in the lower unit doesnt have any water in it. I do have reason to believe that the previous owner swamped (submerged) the rear of the boat at one time( the shower pump motor was full of rust and wasnt working and he said he had replaced the engine a few years ago), so i'm thinking it could be from that. everything works good and the u joints are in good shape other than that.

thanks,
Paul

Re: drive unit u-joint rust?
 

Hard to say, but for $50 a new one can be had for a the piece of mind! New-joint

I assume if it operates smoothly it would be okay. Then again it sucks getting towed in.

Re: drive unit u-joint rust?
 

Water intrusion due to cracked/leaking drive boot possibly.

Re: drive unit u-joint rust?
 

That's a good possibility, Larry. The drive boot looks a little exhaust scorched on the lower side of it, like the engine was running with the unit tilted up. I have the two piece exhaust tubes instead of a bellows down there for that

Re: drive unit u-joint rust?
 

Best take a close look at the gimble bearing too Paul.:wink_thumbup:
Rust has a bad habit of traveling to different areas quickly.

Re: drive unit u-joint rust?
 

Ill check that, too. I'm learning as I go, here. I'm a pretty good mechanic when it comes to Chevys and Peterbilts, but a mercruiser out drive is new and unfamiliar territory for me. How hard is it to change the gimbal bearin out? I replaced the shift cable boot which meant I had to remove the shift cable. Getting that thing back in there was a major headache and made for some colorful vocabularies being heard by my neighbors from deep inside my boat, lol

Re: drive unit u-joint rust?
 

Paul take a look in the Mercruiser Manual in the "Maintenence & Repair" section.
It will show you the process.
In my opinion , it isn't a real tough job , but you do need a couple specialty tools.
I have used a slide hammer for removal with no problem for the actual removal of the bearing.
Also , a piece of 3" schedule 80 ABS pipe works well for installing it and the front seal.
You can pick up a alignment tool on Ebay. They have seal/bearing installer adapters for the alignment tool at a good price too.
Boot , PITA but doable. 50.00 tool for installing it is also available to make your life easier.
There was a seller on Ebay selling a complete install kit , for around 300.00.
Might want to have a marina do it for you , but I don't know what they would hook ya for price wise.:confused:

Re: drive unit u-joint rust?
 

Larry,
I may take it to my local boat shop and have them install it for me, since it requires special tools. I know it'll cost some $$, but I'll know it's done right since I dont have experience with this sort of thing. I'd hate to fork out the money on tools made only for that purpose to use very rarely and still take a chance of screwing it up. I've read that this thing has to be lined up perfectly with the motor. With all the uknowns that I've found with this boat so far, I'm a little leary about skipping by something that could be serious. It's very obvious to me that the previous owner did not take care of this boat, period. It sat out in the Texas heat for two years not being used and never covered up. First time I launched it, i could hear water trickling in around the motor. Called the previous owner just to ask some questions and he admitted that it took on water for a long time and he just ran the bilge all the time instead of fixing it! I've tried uploading a pic of my drive unit on this message so you could see what I'm talking about with the rust

Re: drive unit u-joint rust?
 

Good photo. How are the splines on the shaft? If you have grease with aluminum grindings in the splines your coupler may be on its way out as well. Just something else to look at. Did you get the drive shaft bellow as well?

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Re: drive unit u-joint rust?
 

the splines look good, didnt see any metal shavings on the shaft. grease looked a little dry, though. I dont have a new u-joint boot but will probably go back with a new one so i dont have to mess with it later. the one on there doesnt look too bad. dont see any cracks but the lower side of it has exhaust soot flaking off of it