Milky drive oil

Bughorns

Cadet
Joined
Nov 29, 2015
Messages
26
If I have milky 290a drive oil should I automatically assume that all seals need to be replaced? Or just the ones that leak? I read a post stating I should change the seals behind the u joints. Any help is appreciated
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,617
If the seal behind the u-joint failed, the only way you would have water in the oil would be if your bellows failed and there is water in there. If the bellows do fail, it's almost automatic for water to get in the oil since that seal never expects to have water against it.

I would pressure test the drive and replace only the seals that leak.
 

Mo1

Petty Officer 3rd Class
Joined
Dec 11, 2015
Messages
76
Thanks Bruce. Ive been mostly going at it from the bottom., The outer side of the seal didn't leak at all it was the middle part were the shaft inserts
 

Bughorns

Cadet
Joined
Nov 29, 2015
Messages
26
Thanks Bruce no water in bellows. Think it was coming in from dipstick or prop shaft. I will pressure test next
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Jul 23, 2011
Messages
51,254
if you are leaking in more than one place, get a complete seal kit.

also, if you do have any rust on the input shaft, you probably should attend to the u-joints. replacing the input shaft requires a new crush sleeve, input shaft seal, input shaft crush washer o-ring and a few other o-rings.

your VP should be able to hold 15psi and 12-15 inches of vaccuum.
 

peejcj8

Petty Officer 2nd Class
Joined
Jan 8, 2006
Messages
102
Merry Christmas Guys!

I'm having a similar issue, so I'm going to jump in.

VP280 drive. I drained the outdrive yesterday and the oil was milky. I then loosened the drive bellow and milky fluid came out of it also. I put pressure on the drive without fluid and it holds 15psi. I filled the outdrive with oil and put 20psi on it again, still 20psi an hour later and no leaks of oil.

The drive bellow looked in good shape and is about 2 years old. I ordered a new one and will replace next week.

My only guess is the drain plug was the issue, it had a split in the oring, but I never noticed any leaks.

How did the milky oil get in the bellow if it holds pressure?
 

PatinIdaho

Chief Petty Officer
Joined
Oct 7, 2014
Messages
405
Merry Christmas Guys!

I'm having a similar issue, so I'm going to jump in.

VP280 drive. I drained the outdrive yesterday and the oil was milky. I then loosened the drive bellow and milky fluid came out of it also. I put pressure on the drive without fluid and it holds 15psi. I filled the outdrive with oil and put 20psi on it again, still 20psi an hour later and no leaks of oil.

The drive bellow looked in good shape and is about 2 years old. I ordered a new one and will replace next week.

My only guess is the drain plug was the issue, it had a split in the oring, but I never noticed any leaks.

How did the milky oil get in the bellow if it holds pressure?

Do not forget to rotate the shafts when you are doing a pressure test with a drive empty of oil.
 

peejcj8

Petty Officer 2nd Class
Joined
Jan 8, 2006
Messages
102
When you pressure test the drive, you aren't testing the bellows.

I get that, What I don't know is how the drive oil got into the Bellow if the drive holds pressure. Also How did the water get into the drive oil.

Possible scenarios.

1. the drive oil could have leaked into the bellow and then water leaked into the bellow to mix into the oil then that milky oil seeped into the drive?

2. Water leaked into the drive, then that milky oil leaked into the bellow?

I did not rotate the drive during testing.
 

Bughorns

Cadet
Joined
Nov 29, 2015
Messages
26
Most likely #2 if u had a leak it mixed with oil and out out the upper gear seals into bellows.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,617
Also what happens is that you get water into the bellows and then water seeps through the oil seal. That seal is not made to keep water out. Water rusts the shaft going onto the drive and then causes the seal to fail allowing oil to go into the bellows.

You need to make sure your bearing in your bell housing has not rusted because of this water in the bellows.

BTW, you should start your own thread with your issues.
 
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