Lower unit oil loss from res.

[ALM]

I loose lower unit lube from the reservoir. Some goes in the bilge, but I see no oil route. Some seems to get out by the outdrive, under the rubber hoses.
I seen and felt the oil when I flushed. Outrdive seals are good, no oil leaks. Unit has lube all the way up to the top vent hole.
I know there is a tube that goes through from the reservoir to the outrdive. How do I check the connection?
525, ITS Bravo XR.

[MOBILEMERCMAN]

I would suggest cleaning the hose and all fittings well and check after each use.

You said all seals are good. Has the drive been off and serviced recently? If the yoke seal is leaking it will leak into the bellows and eventually into the bilge. I would think if the hose was leaking outside the transom there would be water mixing in the lube.

[ALM]

I would suggest cleaning the hose and all fittings well and check after each use.

You said all seals are good. Has the drive been off and serviced recently? If the yoke seal is leaking it will leak into the bellows and eventually into the bilge. I would think if the hose was leaking outside the transom there would be water mixing in the lube.

Thank you. I will check the lube, and replace. Didn't see any water mixing removing the top vent plug. No recent service.

[Geronimo36]

I loose lower unit lube from the reservoir. Some goes in the bilge, but I see no oil route. Some seems to get out by the outdrive, under the rubber hoses.
I seen and felt the oil when I flushed. Outrdive seals are good, no oil leaks. Unit has lube all the way up to the top vent hole.
I know there is a tube that goes through from the reservoir to the outrdive. How do I check the connection?
525, ITS Bravo XR.

Couple things to check;

1. You said there is oil in the bilge? It may be coming in thru the driveshaft opening and if that's the case you ahve a bad upper seal.

2. You said there seems to be oil coming from under the rubber hoses? (bellows). This could be from oil reseviour hose/fittings that go from the transom assembly to the gimbal helmet. It's a small hose and it's held in place by plastic clips that are prone to breaking over time. Lift up the drive all the way and visually inspect the hose, it will attach to the helmet on the right hand side, follow the hose to the transom assembly and check for oil leaks. The hose itself may even have a pin-hole.

3. May also have a bad o-ring between the drive and helmet mating surfaces. When people install the drive they sometimes misalign the o-ring or don't use adhesive to hold it in place.

4. The small o-ring in the top cap of the drive might be pinched.


Just a few suggestions, hope this helps!

[ALM]

I trimmed it up, looked and felt all around. Did not see or felt any small tube. Must be inside the rubber bellows. There is oil around the bellows. etc.
Never removed a Bravo before. Worked on Alphas. Quick comments on outrdive removal?
Gear in forward? etc.? Anything I should know before I remove it and check the bellows and tubes?

[Geronimo36]

There is a small hose that goes from the outside of the transom assembly to the bellhousing. If you're looking at the back of the boat it's on the right-hand side somewhat even with the hinge-pin. Merc doesn't have good pictures but if I remember the hose is roughly 3/8".
http://www.mercruiserparts.com/Show_...tor+Components
http://www.mercruiserparts.com/Show_...c=Bell+Housing


You don't need to put it in Forward like an Alpha, just unbolt and pull it off. There is a claw-like fitting on the right hand side that when you pull the drive back it opens up to allow unhooking of the shift cable. Actually, just above the shift cable is where the remote oil fitting is.

[ALM]

Removed the outdrive. There was gear lube in the bellows and under it. Just above the anode. (see pic. tip of scre driver)
Where does it come from? O rings and seals seemd to be ok.
I saw the end of the oil tube with a little valve on it, and there was a ball in the outdrive where it connects. I think they act like a valve. There is an o ring around the connection but looked ok. Drained the lower unit. Oil is good. No shavings or water, so I guess it's the reservoir system or tube issue. Any ideas how to fix?

[MOBILEMERCMAN]

I say drain and pressure check the drive.. You are most likely going to find a leaking input shaft { yoke seal } leaking. I would suggest you bring it to a shop. There are a few special tools needed to repair this.

The lube was in the bellows and spilled out as you removed the drive.

If the boat is 5 to 7 years old the bellows are due to be changed.

[ALM]

I say drain and pressure check the drive.. You are most likely going to find a leaking input shaft { yoke seal } leaking. I would suggest you bring it to a shop. There are a few special tools needed to repair this.
The lube was in the bellows and spilled out as you removed the drive.
If the boat is 5 to 7 years old the bellows are due to be changed.

Thanks Jim, but the oil in the bellows was not from spilling during removal.
There was no oil in the reservoir and I slid the drive out easily and quick. I made a track so I can slide it out. I also drained some of the oil from the lower unit. I can assure you it was not from the removal process. There were way too much oil in the bellows from a few seconds of slippin the drive out out time. The boat/motor is only 2+ year old. I'm not sure what you mean by " yoke seal " leak. The shaft and everything around it is ok. I can do a preassure check. I have the tools to do it and will do it Monday PM. I don't think it's "drive leak". Seems to be something with the reservoir tube and conection to the outdrive. But not sure.

[MOBILEMERCMAN]

I am saying the lube in the bellows can only get in there if the yoke seal { input shaft } is leaking..The lube you mentioned on the anode is from removing it.. If you could see lube on the bellows before you removed it I would think the bellows is on its way out or you have 2 leaks.. Typically they last more than 2 years.. The yoke seals leak it is not un common. The seals also wear grooves in the yoke... There is no way to determine it visually. The only way is pressure checkng the drive.. I would bet you lunch it is the yoke seal if I lived near by.

If you have the spanner wrench, drive stand, some drivers, a roller torque inch/lb wrench it is a simple repair.

[2112]

There are a few special tools needed to repair this.

.

Is it hard to swap out the yoke seal/input shaft assembly? The seal is an O-ring, correct?
.

[MOBILEMERCMAN]

If you have the spanner wrench, drive stand, some drivers, a roller torque inch/lb wrench it is a simple repair.

In addition to these you will need basic hand tools and a torque wrench. There are some specific procedures and specs to follow. Rolling torque on bearings. If by chance you over tighten them you will need a press and jaws to loosen before continuing. You will need to ensure the timing marks on the driven gears are timed correctly. You need to measure your torque wrench and spanner wrench to calculate the proper value on torque wrench to achieve 200ft/lbs.

Michael the service manual I previously mentioned to you has all of this and more.

[MOBILEMERCMAN]

Is it hard to swap out the yoke seal/input shaft assembly? The seal is an O-ring, correct?
.

There is an O ring and a seal. Its the seal that is doing all the work. It rides on the spinning shaft.. The o ring is sealing the housing to the cover nut and related pieces.

It is easier than changing a bellows. Just requires a different set of tools. Once the drive is off it typically takes about an hour. The variable is when you correct one leak and pressure check you may find another. On an older drive you may as well change all the seals. I believe the flat rate on that is 3.5 hours on the upper. Of course a few more tools too .

[2112]

Which manual should I get and where do you suggest I get it? I have one but it is old and not an official Merc manual so some details are missing.
.

[ALM]

Not knowing the actual term. What is the yoke seal? Have a picture? Are you talking about the upper drive shaft/U joint shaft that goes into the upper drive housing? Is that the "yoke" you referencing?

[MOBILEMERCMAN]

Which manual should I get and where do you suggest I get it? I have one but it is old and not an official Merc manual so some details are missing.
.

You can order one at any Mercruiser dealer. The drive is a different manula than the motor.

[MOBILEMERCMAN]

Not knowing the actual term. What is the yoke seal? Have a picture? Are you talking about the upper drive shaft/U joint shaft that goes into the upper drive housing? Is that the "yoke" you referencing?

Yes, the yoke is the piece that holds the u joint and enters the drive housing. It is the seal that rides on the yoke that is likely to be your problem.

http://www.mercruiserparts.com/Show_...ift+Components

25 is the yoke 28 is the seal. Its all there

[Geronimo36]

Couple things to check;

1. You said there is oil in the bilge? It may be coming in thru the driveshaft opening and if that's the case you ahve a bad upper seal.

Removed the outdrive. There was gear lube in the bellows and under it. Just above the anode. (see pic. tip of scre driver)
Where does it come from?

[B]I say drain and pressure check the drive.. You are most likely going to find a leaking input shaft { yoke seal } leaking. I would suggest you bring it to a shop. There are a few special tools needed to repair this.

The lube was in the bellows and spilled out as you removed the drive.

If the boat is 5 to 7 years old the bellows are due to be changed.[B]

Thanks Jim, but the oil in the bellows was not from spilling during removal.

There were way too much oil in the bellows from a few seconds of slippin the drive out out time.

I am saying the lube in the bellows can only get in there if the yoke seal { input shaft } is leaking..The lube you mentioned on the anode is from removing it.. If you could see lube on the bellows before you removed it I would think the bellows is on its way out or you have 2 leaks.. Typically they last more than 2 years.. The yoke seals leak it is not un common. The seals also wear grooves in the yoke... There is no way to determine it visually. The only way is pressure checkng the drive.. I would bet you lunch it is the yoke seal if I lived near by.

If you have the spanner wrench, drive stand, some drivers, a roller torque inch/lb wrench it is a simple repair.

There is an O ring and a seal. Its the seal that is doing all the work. It rides on the spinning shaft.. The o ring is sealing the housing to the cover nut and related pieces.

It is easier than changing a bellows. Just requires a different set of tools. Once the drive is off it typically takes about an hour. The variable is when you correct one leak and pressure check you may find another. On an older drive you may as well change all the seals. I believe the flat rate on that is 3.5 hours on the upper. Of course a few more tools too .

Not knowing the actual term. What is the yoke seal? Have a picture? Are you talking about the upper drive shaft/U joint shaft that goes into the upper drive housing? Is that the "yoke" you referencing?

Yoke seal is also known to some as an upper seal. the seal is located behind the yoke (u-joint and socket assembly) when it it's held into the drive by a spanner nut.

When the drive is on the boat that bellows area gets sealed by the drive housing and when the seal goes bad all the oil collects in the bellows area. When you remove the drive it oozes out..

You mentioned there was oil in the boat, I had suggested the upper seal (Yoke) was bad in my first post!

[MOBILEMERCMAN]

You mentioned there was oil in the boat, I had suggested the upper seal (Yoke) was bad in my first post!

Frank we agree again. I was first

[2112]

You can order one at any Mercruiser dealer. The drive is a different manula than the motor.

Yeah, Mine is a SELOC aftermarket manual. Not so great.
.