Question, More for the Professional Techs / Mechanics

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hotajax

GreatGrady Captain
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What is an average price to replace the seals in a lower unit? Should this job be done on a routine basis, or leave it alone? What say the experts?
 
I am no expert but I have owned boats for years and do all of my own work. Your question is loaded. Do you boat in sandy or muddy areas and beach a lot, have you hit anything or wrapped mono or worse braid around you prop shaft? If these are the case then you need to keep a closer eye on it. Drain the lower unit oil look at it; you will know immediately, if it looks like a milk shake you have a problem. If it does have it pressure tested, 99.99% probability it has a leak.

If you are asking relative to normal use then my comment is to pay close attention to the quality of the oil that is coming out of your lower unit each year. And watch for signs in the water of an oil leak, i.e. a small slick when there should not be one around your lower unit assembly. Any sign of a milky color to your oil says you have a leak, period. Have the unit tested and the seals replaced it is shot money compared to a new lower unit. In 20+ years of boating, mostly in salt water, I have had to replace two sets of lower unit seals. One was out of stupidity; the other was due to lower unit deceleration trauma. Come to think of it both were out of stupidity.
 
Not Needed for My Boat Yet....

but was wondering if it should be done routinely. Special tools required? Trips to a machine shop??
 
Pulled my lower units off this weekend to replace water pump and impellars. My mechanic lifted the metal cover over the seal and noticed the metal spring was broken. I mentioned the gear oil was in good shape at end of last season. His advise was it should be checked everytime you change impellar and be replace upon evidence of wear. I might have him replace seals in two weeks even though the seals don't show any wear and would hold for the season.
 
Assuming you don't see a: an oil slick in the water or b: water in the LU oil, the seals are probably OK. The way to test is to do a vacuum/pressure test when the LU is drained. Often there are two seals, one blocks water intrusion and the second blocks oil leakage.
On my Yami you need a special spanner wrench to undo the lock washer and then a tool/hooked pick to whack out the seals. There is a tool to seat the new seals but you can get the job done with a piece of wood dowel or a piece of pipe.
If the seals don't leak, I wouldn't touch them.

If you were to discover line wrapped around the shaft, it it a good practice to do a pressure/vacuum test to make sure that all is OK
 
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