alpha one prop shaft seal

[airshot]

As an avid reader of this forum, I have searched for info on the prop shaft seal removal and installation and have not found much. I have a spare outdrive that was rebuilt but the prop shaft seal was installed backwards and obviously leaks oil. I want to change this seal so I can use the outdrive as this one has the correct gear ratio for my engine. It is a 1983 alpha one off a 3.0 140 hp. Are special tools required? As a toolmaker by trade I can handle the job if I know the proceedures. As always thanks in advance for the great help I recieve on this forum.

Airshot

 

[Eric 3.7LX Alpha 1]

Re: alpha one prop shaft seal

There are some special tools you will need to remove the bearing carrier which is where the seals are. If the prop shaft is grooved and is the cause of the seals leaking. It will require the shaft to be replaced and probably not worth the expense. They can get damaged from fishing line getting wrapped in there.

There are no specs for the tools that are needed for this job.

You can remove the bearing carrier retainer nut and the carrier without the special tools, a puller is needed for the carrier, but will need the lower carrier retainer wrench to torque the nut back in when done.

 

[dubs283]

Re: alpha one prop shaft seal

you will need a special tool for removing the bearing carrier retainer

it is the large notched ring at the aft end of the bullet

it is threaded and torqued to 200 lb/ft

once that is out a large puller is needed to remove the bearing carrier assy

there are actually two seals for the propshaft

if you have the proper manual, it gives step by step procedures for removal and installation

 

[Bt Doctur]

Re: alpha one prop shaft seal

There was/is a threaded tool that slips over the prop shaft and under the seals and screws them out.Easy to make with a lathe 6-8 tpi

 

[airshot]

Re: alpha one prop shaft seal

Thanks for the reply's, nothing is damaged, the person that rebuilt the outdrive told me about the seal, when he installed the new seal he just put it in backwards, not realizing it util he was finished, knew it would be destroyed removing it, so just used the spare outdrive and planned to fix it another day.
This outdrive has the correct ratio I need, just have to replace the outer seal correctly first.

Airshot

 

[airshot]

Re: alpha one prop shaft seal ?

Re: alpha one prop shaft seal ?

Want to be sure we are all talking about the same seal here, if you remove the prop then remove the large washer that keeps the prop from from moving closer to the gear case, it is that seal that you see aroung the prop shaft. Mine has the spring facing the prop and it needs to be turned around. With all the special tools etc it seemed like alot just to replace that seal. Anyway would appreciate a confirmation that seal is the "prop shaft seal" or am I using the wrong terminology. Thanks

Airshot

 

[Bt Doctur]

Re: alpha one prop shaft seal

According to the manual the fist seal faces in and the second faces out.
3B-27, 3B-27 this link
http://www.boatfix.com/merc/Servmanl/6/6B3R3.PDF

 

[natemoore]

Re: alpha one prop shaft seal

As an avid reader of this forum, I have searched for info on the prop shaft seal removal and installation and have not found much. I have a spare outdrive that was rebuilt but the prop shaft seal was installed backwards and obviously leaks oil. I want to change this seal so I can use the outdrive as this one has the correct gear ratio for my engine. It is a 1983 alpha one off a 3.0 140 hp. Are special tools required? As a toolmaker by trade I can handle the job if I know the proceedures. As always thanks in advance for the great help I recieve on this forum.

Airshot

I've made a lot of improvised tools. The special wrench needed to remove the retainer nut can be found for about $50 on ebay. I removed mine using a large punch and hammer because I was going to replace it anyway. You could easily make a wrench using a segment of black iron pipe that fits over the prop shaft. Just weld on some steel to make it fit a 1/2" drive on one end and weld on four spokes each with a tooth to engage the nut. You'll have to do a little engineering since it has to be torqued to 250 ft-lbs. I enjoy the challenge of making these tools.

As far as removing the carrier assembly, I made a puller using two eyehooks, two barrel nuts, two sections of threaded rod, and a harmonic balancer puller I already had. Since the carrier is probably corroded, you may have to use a torch to heat it up, then let it cool, WD40, heat, cool, tapping, etc, to get it out.

If the prop shaft is grooved, try hitting it with some emory cloth to get it smooth. Since the new seals probably won't be in the exact same spot, I'd just replace the seals then pressure test it before replacing the prop shaft. It may be a $20 gamble, but compare that to how much it would cost to replace the prop shaft, which will certainly require many many hundreds of dollars of specialty tools, it's worth the risk to me.

If you go the center punch/new nut route, I suppose a nice marine shop would torque it for you.

 

[airshot]

Re: alpha one prop shaft seal

As always many thanks for the information, the pics from the manual are a great help and the advice on making the tools was great !!

Airshot