volvo 270 leaks oil after u-joint bellows replacement

I took my 270 outdrive in for service after noticing milky water mixed oil dripping from a small leak in my universal bellows. They replaced the bellows and u-joints and o rings and seals. When I picked it up I noticed some oil had dripped down the side of the upper unit. The mechanic noticed it too and dismissed it as oil spilled during filling of the drive with oil.

I took it home and repainted the outdrive with trilux antifouling paint. The next day I noticed a streak oil had dripped down over the new paint. It was not much of a streak, cleaned it and not any more visible oil the next day. Put the muffs on and ran it for about 10 minutes. After that I noticed another small streak of oil had dripped down the port side of the upper unit. Seems like it is coming from the near the top of the upper unit towards the back. I will call the mechanic tomorrow, and ideas in the mean time? I hope no damage has been done. Have not launched it yet just ran it on the muffs.

I doubt it very much that any damage has been done. I would bet your mechanic didnt snug up one or both of the hose clamps to your bellows. Some mechanics squirt a little oil into the bellows as the are assembling so if you ever poke a hole in it you get a telltale of oil on the water to let you know you have a problem. good luck!! take it back to your mech.

FYI here...... These are among the easiest and most simple drives to work on..... but I am always amazed at what I see being done! And I know this because some end up here with me to be fixed..... AGAIN!

In a 270 transmission, the main drive gear is supported via a cylindrical steel tube. This is the "Bearing Box".
This Bearing Box has a shoulder on it.
The shoulder is clamped to the main gear case via the clamping collar.
On each side of this shoulder are a series of shims and on either side of the shim pack is the rubber O-ring seal.
Both of these seals are critical, but the seal on the AFT-most side is very critical!

Taking this all apart and cleaning it correctly is quite a job.
Often the clamping collar and bearing box will stick together.
Some mechanics do not take this further apart, and are simply changing out the bearing crosses, and then calling it a day.

If for some reason these two O-rings were not replaced, we have issues with a leak in this area..... not to mention one other O-ring and the main seal right in this same area.

There are a combination of Nineteen (19) O-rings, gasket and Seals in this drive that would be replaced if they had done all of them correctly.

Did you get your old parts back?
Some shops will keep these so you can see what has been replaced.

If you go back to them to have this taken care of...., ask a few questions:

Did the drive hold during the pressure/vacuum leak down test?
Was the pressure test done dry or wet? (makes no difference on the vacuum test)
What were the times holding in either direction?
Ask them how many seals/O-rings this complete "re-seal" involves.
Ask if the shift mech seal is directional!
Ask if the top cover gasket was replaced.
Ask what product they are using for a sealant behind each lip seal.

Point in telling you this is........, if you plan to have this same shop re-do this, make sure that you are comfortable that they know what they are doing.... and especially pay attention to the "dry" leak down test.

Ironically, I have one here right now that I cannot find a leak in, and it's driving me nuts.
I've never before had one fail a pressure/vacuum leak down test.

Had your shop done the leak-down test, they would have found this!
To send on out the door that ends up puking gear oil.... that's not good!
.

Thanks Toto and RicardoMarine for the replies and insight. I took it in and spoke to my mechanic. He was suprised too and will drain the drive and do a pressure check. I feel he will make it right. Glad I did not immediately launch it and get salt water in it.
Hope it turns out well, keep you posted.

PS, He didn't pressure check it before it went out the door. Bet that won't happen again.

No pressure check after splitting the upper and intermediate???? Shame on him. It only takes a few minutes.

cpt_pete said:

PS, He didn't pressure check it before it went out the door. Bet that won't happen again.

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I hope you are right.

Just an update of my original post. My mechanic pressure tested the outdrive dry today for about 2 hours and it held 16 lbs. Refilled with oil, and called me to tell he couldn't find a leak under pressure, used a lot of soup to help identify it and could find none.

Stopped by to check it out in person and low and behold if it had a drip of oil that seemed to be coming from the port nut on the bolt that holds the upper gear housing to the intermediate housing. Showed it to my mechanic who couldn't believe it. He said he'd pull it apart and and put a new o ring or seal in I can't remember exactly. Said he did not understand it as it has new seals and o rings. Any ideas? He is an experienced volvo mechanic. I suggested he use a little sealer ? I'm not the expert, any ideas or insight would be appreciated.

Don't know, maybe some debries got in between o-ring and the groove during assembly?

My observation:

An outdrive undergoes a mild pressure increase as it warms up, even though the temperature and rate of expansion is very very low!
As it cools back down, it may undergo a mild negative pressure.... again, very low on any scale.

If the lip seals hold during pressure (and most lip seals increase their holding ability when under pressure), when the pressure returns to what may be a mild negative pressure (when lip seals are at a disadvantage) they may allow water ingress.

Many of your seals in this drive are "double" lip... or single lip seals installed "back-to-back" (prop shaft).
However, the main drive seal is a single lip, faced in a direction best suited for pressure.

Point being, it is equally important to pull a negative pressure (aka vacuum) during your "leak-down" test.
That's why this is referred to as a "Pressure/Vacuum" test!

This may also catch an O-ring that is holding under pressure, yet may not be under negative pressure.

Positive Pressure and Negative Pressure may cause any O-ring and/or seal to act differently.
This is also why we don't necessarily have 100% luck when pressurizing a suction hose to find a suction leak! Physics!

O-ring grooves need to be squeeky clean when going back together. A little salt or crud displaces the o-ring and wa-la, leak. No sealent, just good old fashioned grease and put it back together. No seal where you're talking.

boatdoc55 said:

O-ring grooves need to be squeeky clean when going back together. A little salt or crud displaces the o-ring and wa-la, leak. No sealent, just good old fashioned grease and put it back together. No seal where you're talking.

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Gary, sorry for dissenting, but I am a firm believer of applying Perfect Seal both to the o-rings and the whole mating area between upper gear assembly and intermediate housing. It won't do any harm and, in addition to assist with sealing, it will prevent salt water to corrode the otherwise exposed aluminum parts.

To each his own, El. I've taken a bunch apart over the years and cringe when I have to scrape, sand, file, even bead blast what some knucklehead used for sealant on O-rings and their grooves. I have changed bellows on boats that I had done many years before and that good ole' blue grease is still there, right where I put it.
Perfect Seal is perfectly alright, get the pun, with me as it doesn't harden like cement and I believe that the "aviation" by Permatex is basically the same and I do use it quite often. I'll use "aviation" on not perfect surfaces such as intermediate and upper housings that someone has pryed apart and the one place I use it ALWAYS, is the hose nipple seal, both sides.
If we all did everything the same wouldn't it be a boring world. Back in the old days never did see a virgin drive with sealant, just the white assy lube they used which did get a little hard over the years.

boatdoc55 said:

I'll use "aviation" on not perfect surfaces such as intermediate and upper housings that someone has pryed apart and the one place I use it ALWAYS, is the hose nipple seal, both sides.

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Interestingly enough, this is what I have been recommending over and over.

You are correct, Perfect Seal has a similar texture as "aviation gasket" and it will never harden, so I find it useful in virtually any area where you want to avoid corrosion or leaks. I also use as anti-seize compound in threads and metal parts exposed to salt water.

My old boss, who retired a few years ago from the marine business and is currently enjoying the rest of his life, was the one who introduced me to the wonders of Perfect Seal. I'm glad he did.

el_pescador said:

.........
You are correct, Perfect Seal has a similar texture as "aviation gasket" and it will never harden, so I find it useful in virtually any area where you want to avoid corrosion or leaks. I also use as anti-seize compound in threads and metal parts exposed to salt water.

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I do use Perfect Seal on drives that will be in salt water.

As for Anti or Never-Sieze, just an FYI for those reading this:
The automotive versions of this are excellent for anything above the water line..... engine components, bolts, ect..... but they do contain conductive elements that will corrode and expand if used below the water line..... particularly salt water!
If you DO USE this, the name changes from Never-Sieze to Always-Sieze.... so be careful!
For this (and I assume is what Eduardo is speaking of), there is a Marine version of Anti-Sieze that contains NO conductive materials.

Perfect Seal works for threaded parts as well. The clean up is far less offensive than what any corrosion issues will present!