Upper drive shaft leaking?

[Fiat4Fun]

Howdy,

Just took my 1986 Chris Craft with a Alpha One into get winterized. They pressure tested the drive, and was low. Removed the drive, and found a small bit of oil in the bellows. It appears the seal where the drive shaft comes out may be leaking a bit. He also notice the oil was dirty ( not cloudy ) after this seasons 55 hours. It was changed out last winter, and when he drained the drive there were some metallic on the magnetic plug.

The lower end was replace with a Sierra unit in 2010, but the upper is original. Boat has about 750 hours.

Is it safe to just replace the yoke and seal or is there more to it? Is a bit of metallic on the drain plug a concern? No large metal pieces came out....

Any advice is greatly appreciated,
Bob

 

[Rick Stephens]

Re: Upper drive shaft leaking?

A little metal 'fuzz' is normal on many working transmissions and not indicative of a failure.

Chips are a dead giveaway that you need to open it up and find the problem.

Big conundrum when you see any amount of metal on the magnets that heightens worry is wondering if it will fail you out on the water in a dangerous situation. Or wreck a trip. Anything more than really fine stuff on the magnet, time to go inside.

Best of luck on finding minimal problems.

Rick

 

[mercs4mark]

Re: Upper drive shaft leaking?

He has to get into it to do the seal so I would have him inspect the bearings for any pitting or excessive wear as well as the gears.

 

[Bondo]

Re: Upper drive shaft leaking?

Howdy,

Just took my 1986 Chris Craft with a Alpha One into get winterized. They pressure tested the drive, and was low. Removed the drive, and found a small bit of oil in the bellows. It appears the seal where the drive shaft comes out may be leaking a bit. He also notice the oil was dirty ( not cloudy ) after this seasons 55 hours. It was changed out last winter, and when he drained the drive there were some metallic on the magnetic plug.

The lower end was replace with a Sierra unit in 2010, but the upper is original. Boat has about 750 hours.

Is it safe to just replace the yoke and seal or is there more to it? Is a bit of metallic on the drain plug a concern? No large metal pieces came out....

Any advice is greatly appreciated,
Bob

Ayuh,.... as noted, when the seal is replaced, he's in deep enough to completely access the condition of the upper unit,...

At that point, decide to either repair or replace,...

'n abit of fuzz on the magnet is pretty normal,...

 

[Fiat4Fun]

Re: Upper drive shaft leaking?

Thanks for the responses.
I went over to the shop and picked up the outdrive unit to take it to a Mercrusier guy. The guy who was doing the winterization did not have the spanner tool to take it apart. I looked at the metal material, and it was just metal fuzzy, nothing big. Sounds like that is normal.

The Mercruiser guy looked over the drive unit, and mentioned that 9 out of 10 of those driveline seals need to be replaced if water got to the back side of the seal. The seal is designed to keep oil from going out, not from stopping water in.....

He said he would check the bearings and all the tolerances, along with anything that was obvious. He did say that the upper end is old, and I am getting my use out of it at over 700 hours. Anyway, it's all getting fixed with OEM parts, and we should be good for next year. I saw the pictures of the little bit of oil that was in the bellow area, and it was not excessive.
Thanks again, and will update when I go get the drive back