Alpha 1 Gen 2 upper gear preload

CaptRedBR

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May 23, 2021
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I just replaced my oil seal and replaced my yoke and now I have it all together and I’m attempting to set the bearing preload. The issue I’m having is that the friction between the new seal and the new yoke alone is significantly greater than 5in/lbs. How am I supposed to get an accurate reading on the bearings when the friction between the yoke and oil seal introduces its own resistance?
 

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CaptRedBR

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For reference the serial is 0L726xxx and here is another photo of the yoke and seal.
 

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dubs283

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did you clean the seal surface of the yoke and grease the seal lip?

preload is measured with a light amount of gear lube in the bearings as well
 

CaptRedBR

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did you clean the seal surface of the yoke and grease the seal lip?

preload is measured with a light amount of gear lube in the bearings as well
Yes all greased per manual. The entire assembly spins on top of the retainer nut without the bearings even spinning. If I hold the bearing cups still the reading is like 8in/lbs with the nut just finger tight.

Unfortunately the nearest boat mechanic that will work on I/Os is hundreds of miles away so I may just need to order a new outdrive online.
 

dubs283

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The entire assembly spins on top of the retainer nut without the bearings even spinning. If I hold the bearing cups still the reading is like 8in/lbs with the nut just finger tight.
you are correct in holding the bearing races stationary while checking rolling torque, having that high a reading without the nut even tightened indicates something is likely installed wrong/backwards

verify that you've assembled everything correctly and check again
 

CaptRedBR

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you are correct in holding the bearing races stationary while checking rolling torque, having that high a reading without the nut even tightened indicates something is likely installed wrong/backwards

verify that you've assembled everything correctly and check again
Just the yoke passing through the seal with nothing else assembled provides enough resistance to be beyond 5in/lbs. I took pics at disassembly, it really comes down to the yoke and the seal being a tight fit. Maybe I need a different seal?
 

achris

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For reference the serial is 0L726xxx and here is another photo of the yoke and seal.
I'm having trouble with that serial number. Can you post the full number please. Makes it difficult to see what you have when I can't look it up.

Chris........
 

CaptRedBR

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I'm having trouble with that serial number. Can you post the full number please. Makes it difficult to see what you have when I can't look it up.

Chris........
0L726551. The seal I installed looks different than the one I took out, although the one I took out was so corroded and shredded it was hard to tell what was the seal and what was the aluminum. I had to use a wire brush and a magnet to find the edge it was so corroded. This pics are of the disassembly and after I removed the seal. The new seal I got is double lipped
 

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CaptRedBR

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OEM seal is not double lipped, its design allows for air to pass through when the drive cools which is why a vacuum test will fail on a fully assembled drive
Well that would explain a lot. This is the kit I got:

Anyone have a part number for the proper seal?
 

achris

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...Anyone have a part number for the proper seal?
Go to Mercruiserparts dot com. Put your serial number in and search the listings. All the parts for your drive are there, including that seal. (which is why we ask for COMPLETE serial numbers ;))...
 

CaptRedBR

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Go to Mercruiserparts dot com. Put your serial number in and search the listings. All the parts for your drive are there, including that seal. (which is why we ask for COMPLETE serial numbers ;))...
The bearing cups for mine don’t seem to match what is supposed to be in there. I purchased my boat from a marine mechanic so I’m guessing he swapped out the gear set at some point, which is why I worry about using oem part numbers for sourcing parts (although that double lipped seal didn’t seem to work either).
I’ll try the oem one next. Thanks guys
 

achris

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What's your tooth count on the drive and driven gears?
 
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