Gear lube in hull

[Dewater]

Have been dealing with gear lube in the hull all season. Can’t find leak on hoses or the bottle all appear to be ok. Pulled outdrive off for ujoint replacement. Found the drive bellow full of gear lube. Is it possible for the gear lube to back flow into the hull from that bellow through the gimbal bearing? If so what causing that leak or where is it coming from ? Thanks
Mercruiser 5.0 alpha1gen2

 

[Scott06]

Have been dealing with gear lube in the hull all season. Can’t find leak on hoses or the bottle all appear to be ok. Pulled outdrive off for ujoint replacement. Found the drive bellow full of gear lube. Is it possible for the gear lube to back flow into the hull from that bellow through the gimbal bearing? If so what causing that leak or where is it coming from ? Thanks

Yes if bellows fill up from input shaft seal leak they will end up in the bilge as the bellows gets full. There is a drain hole from bellows into the bilge.

It is not a ton of work to do the input shaft seal. You need the merc spanner (or aftermarket copy) to take the big nut off the drive input and a inch lbs torque wrench to set up the preload on the bearing when reassembling.

often the drive yoke will get a groove worn in it from the seal and needs replacement or a speedi sleeve otherwise new seal will leak. Would be good to pressure test the whole drive as other seals may also be leaking

Not sure how bad the leak is but if you have a drive lube bottle you can keep toping it up to get through the rest of the season and fix the drive over the winter. If you clean out the bellows likely it will take a while to fill back up and start overflowing to the bilge again

 

[Dewater]

Thanks yes I’m hoping to make it through this rest of summer. Where is the input shaft seal located. I have some knowledge but it’s been trial by fire. Also what the best way to pressure test this?

 

[Scott06]

Here is a link to the stickies on pressure testing a drive

Drive Pressure/Vacuum Check

I have a 1995 bayliner capri, 3.0 alpha1-Gen11... I'm going to try and make up a contraption to perform a pressure check on my drive. I know I saw a post here that had someones pictures of one they had made... Can anyone help me out,, I can't seem to find it. (would this be something that NAPA...

forums.iboats.com

input shaft seal is where the driveshaft comes into the upper drive. When you took your drive out the drive shaft has splines on the end with two u-joints. You have to remove the drive shaft from the drive.

Get a factory manual #14 it will be laid out in there. Here is a parts break down of the upper- #19 is the seal you need to replace. You can input your drive serial number on that site and takes you right to the drawings.

MerCruiser Alpha One (Gen. II) 1998 & Up Driveshaft Housing & Drive Gears Parts

MerCruiser alpha one (gen.ii) 1998 and up driveshaft housing and drive gears parts. Buy a genuine Mercury Quicksilver or aftermarket part.

www.marineengine.com

How much lube is it leaking. As long as the reservoir keeps the drive full there should be no issue for a month or two. The lube bottle has a low level alarm

 

[Dewater]

I fill the bottle a use boat all day seems to leak down over night or when it sits then top off bottle the next morning. Never had it go low enough for the alarm to go off.