Alpha 1 Gen 1 Shift shaft seal

[tzmanyndvl09]

Hello all, I'm new to iboats,

I was working on an Alpha 1 gen 1 lower unit that I got off craigslist for my boat. the unit was in way better condition then my old one. After I installed it, and ran the motor (with the muffs on, and water was pumping strong) I turned the motor off and went back to look for leaks. I noticed a steady stream of gear oil coming out of the weep hole on the starboard side of the lower unit just above the prop towards the front of the unit. After my research I found that the cause was most likely the shift shaft seal. The prop was off and there was no oil coming from the prop seal. My question is, is the shift shaft seal hard to replace, and if so what all do I need, Tools, Part numbers, etc. (and if anyone knows the parts numbers for the impeller replacement that would be great too i mean im down there anyways might as well change it!)

 

[Watermann]

Did you replace the o ring on the oil passage pass through before mating the lower to the upper?

 

[tzmanyndvl09]

I actually found the leak. The lower unit pressure test went great, What leaks is the vertical drive shaft oil seals where the lower unit vertical drive shaft meets the upper unit vertical drive shaft. There are 2. I got one out, but I do not know how to get the second one out without scratching the drive shaft. Any ideas????

(I know this is a new question, but its my original post, is that okay?)

 

[stonyloam]

Are you talking about # 10 & 11 here https://www.mercruiserparts.com/Sho...br=80&bdesc=DRIVESHAFT+HOUSING+AND+DRIVESHAFT ? I am not absolutely sure, but I think you only need to replace the lower seal. It is quite common for that one to fail.

 

[tzmanyndvl09]

I got the lower seal out, then I re-pressure test and bubbles come for around the upper seal. So I believe that I have to change the upper seal as well. From what I am seeing, there is a lip that impeds pulling the upper seal from the bottom, SOoo i believe i am going to have to take the drive unit apart. NOW! can I just take out the upper horazontal drive shaft, and not take it apart, and just remove the veritical stuff.... or does that require shims and such?

 

[stonyloam]

I think you should replace the lower seal, put it all together THEN pressure test it. That is WAY easier than disassembling the driveshaft housing to replace a seal that may not have any impact on your problem. If it holds pressure you should be OK. Hopefully someone with a little more expertise will chime in here.
I think, to get to that upper seal you would have to disassemble the ENTIRE driveshaft housing, not a job for the faint of heart!

 

[flipbro]

To replace that seal you must take apart upper.. Do not replace just the bottom seal you need to replace both.Its not that hard of a job. And no reshimming is necessary.You will need a spanner wrench thats about the only spacial tool required.Got to stickies at top of page there are sevice manuals and educate yourself alittle on whats required and it will be a peice of cake..By the way if it were me id replace all seals while it was apart .

 

[tzmanyndvl09]

Okay, I just ordered the two oil shaft seals and spanner wrench. Do i need a slide hammer as well, and is there anything i need other than an extension sent and a socket that fits the seals?

 

[flipbro]

No need for a slide hammer. Remove retainer nut with spanner. Remove top cover this requires a 3/8 twelve point socket. Slide the drive gear out first this can be a bit tricky Don't use a hammer. When it comes out pay attention there is a shim pack in there make sure it goes back in upon reassembling. Next lift straight up on the driven gear set aside flip leg over get a long screwdriver and knock old seal out pay attention to the orientation of the seal lips.clean everything up real well install your new seals and reassemble. I use pematex aviation sealer or perfect seal on the top cover o ring and bearing pack oring. As stated I would have ordered a hole seal kit and done the hole upper then you wont have to do it again next year when the yolk seal fails.. O dont forget to torque things down I think 20foot lbs for the cover and 160footlbs for the retainer but mabe double check on those as im not 100 percent sure.. A manual really is a must for these kind of jobs. Good luck.

 

[tzmanyndvl09]

How do I get the bearing out of the drive that sits below the drive gears and just above the upper shaft seal? When I look at the manual it says I have to pull the bearing. And I have the aviation sealant! Thanks for all your information! I'll keep you informed!!!

 

[flipbro]

Its a roller type bearing consists of the bearing and a race. Every thing slides out except the race and theres no need to remove it. Its an easy job with a manual

 

[tzmanyndvl09]

Okay!! awesome!!!!!! Thank you!!