shift shaft seal leak?

cfelton · #1 02-15-2009, 08:25 PM

I had a little free time today so I trimmed up my outdrive and pulled the boat out to give it a good interior cleaning. I removed everything from the cuddy and all compartments in the floor and scrubbed the entire inside down with car wash and clorox and wiped it dry. I put it all back and was walking around it, kinda checking it out when I noticed a drop of gear oil hanging on the bottom of the outdrive. It had been trimmed almost all the way up for about 5 hours. It had leaked 4-5 drops out of the pee hole in the front of the lower unit. This little hole drains the shift shaft chamber so I'm thinking the shift shaft seal is going bad. My question is, can I change the bushing and seal or O ring without taking the prop shaft and all the insides out of the lower unit? I dont have the tool to remove the bearing carrier assembly. I know I have to pull the lower unit off, but how does the shift shaft bushing and seal(s) come out. The book I have dosent go into much detail on this procedure. Its an Alpha one outdrive. Thanks!

spareparts · #2 02-16-2009, 10:30 PM

its not that hard of a job, just drop the lower unit as if you were doing a water pump repalcement, if you haven't done a water pump replacement then it could be a little difficult for you the first time. It does take a special tool, I've done it with a blunt chisel before, but i knew exactly wheer to hit it. The tool is simular to a spanner. Its a socket that engages the two slots in the shift shaft bisuhing to allow you to thread it out, i usually use an impact driver to break it loose, from there, it just threads out, leave the shift shaft in place, unless its not stainless, then replace it with a new one. Slide the new bushing assembly down the shift shaft and tighten it in place, I use a little perect seal on the threads and o-ring

cfelton · #3 02-17-2009, 05:47 PM

Thanks a bunch Spare!! The last time I did a waterpump on it I noticed the shift shaft wobbled a little and it was a little wet around it. I guess I should have changed it then. Ill order one and give it a try. I saw the little tool used to remove and install it on a mercruiser website, but didnt know how involved it was. Thanks again, I owe you one!

Carroll

cfelton · #4 02-21-2009, 05:20 PM

I ordered a complete seal kit from Ebasicpower Wed night. It came in yesterday.I pulled the lower unit off today and saw oil coming out from under the water pump so I removed the entire pump and it looks like I might have a bigger problem. The input shaft has alot of play in it . I can pull and push it in and out about 1/16 of an inch. When pushed in it has side to side play in it too. When I pull out on the shaft it pulls the top tapered bearing in place and the side to side play goes away. Maybe it needs reshimming or something. It ran smooth the last time I ran it and there was no metal particals in the oil. Anybody got any ideas? I hate to put new seals in it only to have it tear them right out again.

How much play is normal on the pinion shaft?

THEFERMANATOR · #5 02-21-2009, 06:50 PM

Quote:

Originally Posted by cfelton

I ordered a complete seal kit from Ebasicpower Wed night. It came in yesterday.I pulled the lower unit off today and saw oil coming out from under the water pump so I removed the entire pump and it looks like I might have a bigger problem. The input shaft has alot of play in it . I can pull and push it in and out about 1/16 of an inch. When pushed in it has side to side play in it too. When I pull out on the shaft it pulls the top tapered bearing in place and the side to side play goes away. Maybe it needs reshimming or something. It ran smooth the last time I ran it and there was no metal particals in the oil. Anybody got any ideas? I hate to put new seals in it only to have it tear them right out again.

How much play is normal on the pinion shaft?

That play sounds normal, and if it wasn't there your drive would self destruct. Spare would know better, but I believe they use a tapered bearing in there so that it tightens as it is loaded. This way as you apply more power it holds the driveshaft more solidly so as to prevent it from wlaking and damaging the gears. Make certain to be careful on the small O-ring seal that allows oil to flow from the 2 halves. Make sure not to damage that area as it will cause havoc if you do so. And the water pump base should be replaced as a whole assembly, not just the O-rings on it.

spareparts · #6 02-21-2009, 09:45 PM

if you have a MC unit( it has the push pin in the top of the vertical drive shaft, then the bearing preloads by pushing down( thats why that pin is spring loaded). If you have an alpha unit, it usues the forces of the gears trying to push them selves apart and preloads the bearing by pushing the shaft up. Either way, that shaft is going to have a bunch of slop in it just sitting there. Go ahead and repalce the water pump base while you're at it, just use two large screw drivers to pry the base upward. Takle speciual care to use hte correct gasket and oring apon reassembly, just match them up with what you took off, thoses kits have a bunch of parts that you won't need in them, they fit several models. ANd liek Ferm said, watch out for that small o ring between the upper and lower unit, I usually glue the new one in place so it wont go any where

cfelton · #7 02-21-2009, 10:20 PM

Thanks fellas, its an alpha one cause it dosent have the pin on top of the pinion shaft. It sounds like its ok, I was kinda worried. Ill replace all the parts and seals in the top end, that should take care of it. When I took it apart , the seal right below the water pump base had poped up and out. thats where the leak was. Im glad I ask you all first! Thanks for all your tips and advice!!

spareparts · #8 02-22-2009, 10:28 AM

couple of other things for you. Make sure you find the o-ring that is on the end of the drive shaft, if it stays up in the upper unit, you'll never get the lower back on. Take a flash light and inspect the seals in the bottom of the lower unit where the drive shaft goes while you aer looking for the o-ring. When you install teh new base, wrap some electrical tape(about three wraps) over the o-ring grove on teh drive shaft, it will prevent the grove from catching the seals on the water pump base when you install it(remember to take the tape off after your done). Put some sealant or lube on the base when you install it, I use Mercruiser pefect seal, don't use silicone, use just need somethign to keep the o-ring from pinching. Once you have teh base down, you should be able to seat it by just pushing down on it, if its a little hard, I slide a piece of pipe over the shaft and tap the base in place. Again, make sure you use the correct gaskets, they give you way to many in that kit

cfelton · #9 02-23-2009, 06:53 PM

I got it in the garage yesterday and replaced everything from the pinion bearing up. I also replaced the shift shaft bushing and seal. It was'nt bad at all. Thanks Spare and Ferm for all your tips and advice. I left it trimed up all nite and all day and no leaks!! Hopefully Ill take it out this weekend and seatrial it.