HighPriority

Thanks Guys, We do change the oil in the drive the way list above. After we replaced the leaking seal the problem did not go away. We filled the drive, and after a short run the rev. was very low, fill the rev again, the same thing happen, filled a third time, and again very low level in rev. Then we pulled the drive off the boat the seal is not leaking. Pulled the upper plug only and about 1 1/2 quarts of oil ran out the top hole.

JaayTeee

Being you added oil to it 3 times and you say there's
no oil in the driveshaft bellows, it's got to be leaking
out externally, and if I we're to have to bet, I would
be laying my money on the prop shaft seal being the culprit.

JJONES

If the drive is not leaking anywere externaly,then you didnt get all the air out when you filled it!A bravo drive is designed to be completely full of oil and have no air in it at all.Removing the upper plug will release oil every time if the drive and res are full!If there is no leak,just keep topping it off until it stays at the full line in res !Sometimes on mine Ive had to add several times after running untill it stayed at the level!Older style drives are checked the way you are checking yours (trs)but not the bravo with res.

Griff

Ain't no way 1.5 quarts came out the upper plug. Its physically impossible, at least with the drive in the down position and on level ground.

The drive holds about 4 quarts total + 8oz in the reservoir.
Above the plug is about 6-8 oz.
The reservoir holds about 6-8 oz.

My guess is you had an air pocket in the drive to start with after you replaced the bad seal.

oldandtired

If oil is coming out of the upper plug, then it seems like you have air escaping the drive through the top or rear cap. I have never had oil above the top plug. The drive will draw in oil if the air escapes under pressure when the drive is hot and then cools off. I have never seen any kind of gearbox that is 100% flooded with oil.

Just my .02

Rene

HighPriority

I agree with you Rene 100%, but we can not find where the air is escaping.

JaayTeee

When you fill the drive the way described
previously, you will raise the oil level somewhat
above the level plug, due to the fact that the air
pocket in the upper ( the area above the level plug, and reservior port) has to support the column
of oil in the hose and the reservior .
( this compresses the air pocket slightly, and raises
the oil level slightly)

If you remove the level plug with the drive mounted
to the gimbal, the oil from the reservior will run out the plug,
til the reservior is empty.

If you have the drive removed and remove the level plug,
you should get a little bit out, but not 1 to 1.5 quarts.
( sorry, I didn't pick up on this in your previous post)



If it indeed has that much oil in it,( when your checking the
oil level with then drive removed) a seal above
the fill plug must be leaking, and letting the air pocket escape.

That leaves the top cap o ring, the rear cap seal,
pinion seal,pinion retainer o ring, or shift shaft seal/o ring as possibilites.

You don't want to run it completely full, you
will blow a seal again

ljsmith1

JayTee

The Drive should not blow any seals if the drive is filled per the Merc procedure. The bottle, and it's line to the top cap should all be filled with oil. The top of the drive should be solid oil (no air). If filled this way, and you are still dropping oil levels, you probably have a leak out of your propshaft or upper seals. If the upper seals are leaking, you would know it because there would be oil in the bellows.

The prop seal is the most likely thing to go. The best way to see how well a the drive is sealed is to perform a pressure and/or vacuum test.

I repeat, the drive is designed to be completely filled with oil. The reservior cap is vented, so no pressure should build up inside the drive.

Good Luck!

-Larry

HighPriority

We have performed pressure test to 18psi, and the drive will hold this pressure for hours.

Pesky Varmint

Oh by the way, we at one time had a chronic problem with the input seal leaking. I had a professional shop in Phoenix tell me that they had to replace several items related to the input shaft, blah blah blah to the tune of thousands.

Several months later, still leaking. Imco rebuilt the entire drive to the tune of $4000.

Several months later, still leaking.

Took it to Larry's in Tucson. All they had to do was "properly" install the seal. If I remember correctly, something about it
not being seated all the way in. Cheap repair too (in the 100's) Been fine now for over two years.

Pesky Varmint