Alpha One Gen 2 Shaft Seal Choice

[Mark R.]

My effort to recondition our Alpha One outdrive continues.
One of the kits I purchased is Sierra seal kit P/N-18-2644.
It came with both types of double seals for the driveshaft.
One is a pair of seals, and one is the combined double seal.
(the seals I removed were the two separate opposed seals).
Which new seal(s) do you think I should I put back in.?
Would the newer style double seal be an upgrade.?
Thanks.!
.

 

[alldodge]

Note at Mercruiserparts list the double lip seal is used on serial numbers 0M400412 and higher
https://www.mercruiserparts.com/bam/subassemblydetail/46516841/28171024

 

[Mark R.]

Note at Mercruiserparts list the double lip seal is used on serial numbers 0M400412 and higher
https://www.mercruiserparts.com/bam/subassemblydetail/46516841/28171024

Hey, thank you for the reply to my question.
The seal I'm referring to is actually #5 in this assembly drawing:

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Our outdrive is slightly older than that (serial number 0F709127).
So ours came with a pair of seals in that location, installed in opposite directions.
I thought I had read that the new double seal can be used, and is an improvement.
The kit I purchased includes both, so hence my question about which to use...
It looks like the double seal would ride on a slightly different location on the shaft.
And I think having the seal on a new fresh spot would also be a good thing...
.

 

[alldodge]

Not real familiar with the Alpha like I am the Bravo. The Bravo changed from 2 seals to a double seal and I installed the new double seal were the prior on was and had no issues.

The Alpha list 0M400410 and below to use 2 seals and 0M400412 and higher to use the double in the notes of the page in your link

You could ask Merc Tech Support on the phone to see if they can advise

 

[Scott06]

Agreed best bet is to use what matches your serial number or contact merc tech support if you want to try the double lip seal.

I would think if you could use either style interchangeably they would just include one seal in the kit not both.

to the OP- do you have manual 14? If you take care to reinstall the shims in same place they were removed you should be ok but worth checking the rolling torque after seal install

 

[Mark R.]

Agreed best bet is to use what matches your serial number or contact merc tech support if you want to try the double lip seal.

I would think if you could use either style interchangeably they would just include one seal in the kit not both.

to the OP- do you have manual 14? If you take care to reinstall the shims in same place they were removed you should be ok but worth checking the rolling torque after seal install

I do have Service Manual #14 and I am following the procedure there.
And I am replacing the yoke seal as well, so I will need to reset the rolling torque.

I thought I had read that the double seal design change did not change the seal cavity.
Which would mean that either seal configuration could be used and would work...

 

[nola mike]

Agreed best bet is to use what matches your serial number or contact merc tech support if you want to try the double lip seal.

I would think if you could use either style interchangeably they would just include one seal in the kit not both.

to the OP- do you have manual 14? If you take care to reinstall the shims in same place they were removed you should be ok but worth checking the rolling torque after seal install

No rolling torque on his drive, it's a basic torque setting.

 

[Mark R.]

No rolling torque on his drive, it's a basic torque setting.

The outdrive serial number is 0F709127.
Along with the driveshaft seals, I plan to replace the yoke seal.
So won't I need to reset the rolling torque after that.?
.

 

[Scott06]

No rolling torque on his drive, it's a basic torque setting.

To do the seal you have to remove the outer race of the bearing above it. There is a rolling torque for the vertical gear and driveshaft. It is changed by changing shims Behind the bearing races. Theroretically if it all goes back in the same with same shims it should be ok. Unfortunately on a gen 2 you need a driveshaft to check it.
we be a lot easier if you could pop the seal in from below…

 

[Mark R.]

To do the seal you have to remove the outer race of the bearing above it. There is a rolling torque for the vertical gear and driveshaft. It is changed by changing shims Behind the bearing races. Theroretically if it all goes back in the same with same shims it should be ok. Unfortunately on a gen 2 you need a driveshaft to check it.
we be a lot easier if you could pop the seal in from below…

Engine is a 1996 Mercruiser 4.3 LX Gen+.
Outdrive is an Alpha One Gen 2 (S/N: 0F709127).
I am currently replacing all the seals in the upper half of the outdrive.
So the "drive gear assembly" and the "driven gear assembly" have now both been removed.
I did not remove any shims or bearing cups when I removed the two driven shaft seals.
All of the metallic parts (gears, bearings, shafts) are still in perfect condition to be reused.
I have disassembled the drive gear assembly in order to access and replace the yoke seal.
So I'm pretty sure I will need to reset the rolling torque on the drive gear bearings.
But I was planning to just reinstall the driven gear assembly back in exactly how I found it.
Does this sound like the correct plan..?
.

 

[nola mike]

To do the seal you have to remove the outer race of the bearing above it. There is a rolling torque for the vertical gear and driveshaft. It is changed by changing shims Behind the bearing races. Theroretically if it all goes back in the same with same shims it should be ok. Unfortunately on a gen 2 you need a driveshaft to check it.
we be a lot easier if you could pop the seal in from below…

Yeah not sure what I was thinking of there...
Doesn't require that on a gen 1, or some gen 1 input shaft seals, so not sure whether I was thinking of the wrong drive, wrong seal, or both