Question about pressurizing outdrive to check for leaks...

[rodgeml1]

My model of Mercruiser has a lube oil reservoir.

Do I need to pull the hose off of the reservoir and cap it, would it be sufficient just to pinch it off, or should I leave the system as is to pressurize it?

 

[Pete104]

Re: Question about pressurizing outdrive to check for leaks...

Remove the drive to pressure test it properly!

 

[rodgeml1]

Re: Question about pressurizing outdrive to check for leaks...

Would you mind please explaining to me the difference having the outdrive off makes versus having it installed on the boat? I'm just curious about the mechanics of it all. It would seem to me that the lube oil system is sealed the same (short of the external reservoir) whether the outdrive is installed or not.

I should've mentioned the outdrive is an Alpha One, Gen II.

 

[NHGuy]

Re: Question about pressurizing outdrive to check for leaks...

Well if you remove the reservoir fitting at the top of the drive you could pressurize it there. If it holds you're good. If it leaks and you can't see where, then you have to remove it to find the air bubbles.
Are you getting milky drive lube? If so just take the drive off.

 

[Brew2]

Re: Question about pressurizing outdrive to check for leaks...

If you remove the drive, you can pressure test because there is a valve that automatically closes the resevoir passage once the drive is off. Make sure you drain the drive lube before pressure testing. Don't put too much pressure in....10 psi or so should do it.

 

[rodgeml1]

Re: Question about pressurizing outdrive to check for leaks...

OK, so I pressurized the outdrive with it installed on the boat. Air was rushing out and I couldn't find where so I pulled it off. Repressurized it off of the boat and had the same result....still couldn't find the source.

I split the lower from the upper and charged them independantly. The lower held pressure like a champ, but the upper had air flooding out of the port where the drive shaft from the lower enters the upper. Is this expected (doubtful) or do i have a blown seal?

 

[dubs283]

Re: Question about pressurizing outdrive to check for leaks...

Don't put too much pressure in....10 psi or so should do it.

the spec is 15 psi for 10 mins

 

[dubs283]

Re: Question about pressurizing outdrive to check for leaks...

the upper had air flooding out of the port where the drive shaft from the lower enters the upper. Is this expected (doubtful) or do i have a blown seal?

reassemble the halves and pressure test it again

this time spray some soapy water around the driveshaft where it enters the upper and look for bubbles

the driveshaft seals need the shaft in place to pressure test the upper on a gen II - this will also test the oil passage quad ring between the halves

 

[achris]

Re: Question about pressurizing outdrive to check for leaks...

Would you mind please explaining to me the difference having the outdrive off makes versus having it installed on the boat? I'm just curious about the mechanics of it all. It would seem to me that the lube oil system is sealed the same (short of the external reservoir) whether the outdrive is installed or not.

I should've mentioned the outdrive is an Alpha One, Gen II.

With the drive installed the fittings that connect the drive to the reservoir bottle are open. Any pressure you blow into the drive will come out the bottle, not be contained (hopefully) within...

Those particular fittings CAN NOT be seal with the drive installed, they are in the bell housing itself. If you're so concerned about pulling the drive (and I don't see why!) then you could clamp off the hose between the transom housing and the reservoir bottle. But I wouldn't guarantee that method, besides, pulling the drive takes 6 minutes and just 2 tools. A screwdriver to release the clips on the end of the trim ram pin, and a 5/8" socket on a long extension to remove the 6 nuts holding the drive to the bell housing. Just remember to put it in forward gear before you start, and disconnect the speedo feed tube (at the top of the lower unit, in front of the shift shaft)....

Chris.......

 

[rodgeml1]

Re: Question about pressurizing outdrive to check for leaks...

With the drive installed the fittings that connect the drive to the reservoir bottle are open. Any pressure you blow into the drive will come out the bottle, not be contained (hopefully) within...

Those particular fittings CAN NOT be seal with the drive installed, they are in the bell housing itself. If you're so concerned about pulling the drive (and I don't see why!) then you could clamp off the hose between the transom housing and the reservoir bottle. But I wouldn't guarantee that method, besides, pulling the drive takes 6 minutes and just 2 tools. A screwdriver to release the clips on the end of the trim ram pin, and a 5/8" socket on a long extension to remove the 6 nuts holding the drive to the bell housing. Just remember to put it in forward gear before you start, and disconnect the speedo feed tube (at the top of the lower unit, in front of the shift shaft)....

Chris.......

You're right....it is easy to get the outdrive off which is what I wound up doing. And I must humbly say (after attempting to test it with the outdrive on) that it's a good thing I did. When I cracked the outdrive loose, A LOT of water poured out of it. When i took a close look, I found that the U-Joint sleeve and the rubber gasket had gotten bound up together and the sleeve tore the gasket up. In fact it appears as though the gasket was put on the transom side of the gimbal sleeve....thats not right is it? Also found that the gasket that sits between the outdrive and gimbal housing is torn. Could that much water have gotten in there with those two issues or am I looking at some bad bellows?

This boat was supposed to be a turn-key ready to go purchase.

 

[dubs283]

Re: Question about pressurizing outdrive to check for leaks...

if the drive/bell housing gasket fails, or the shift shaft bushing/seal has failed AND the large quad ring in the bell housing fails - yes there will be water in the u-joint bellows

also check the u-joint bellows for holes/tears - with the drive off run your finger in the grooves from the inside and check with a flashlite from the outside

check your u-joints and gimbal bearing too - if water has been present in the u-joint bellows for a long time the yoke seal in the upper will be comprimised too

 

[rodgeml1]

Re: Question about pressurizing outdrive to check for leaks...

Update: Took a quick look at the bellows from the outside on my way out the door. The u-joint bellow seems to be intact but the shift cable bellow is torn clean through into two pieces. Looks like I'll be replacing them all.

Is it strange that I'm somewhat relieved about it? :redface: