Bravo 3 loss of lube oil - slowly then rapidly x2

[gcarmich]

Is drive shaft removal, survey, and reinstall a DIY operation? It would be my first but I do have some general experience with mechanical repairs.

 

[alldodge]

It is DIY but you will need some special tools and the service manual

 

[gcarmich]

It is DIY but you will need some special tools and the service manual

I have the manuals. Will investigate tools. Thx

 

[alldodge]

I have the manuals. Will investigate tools. Thx

Look in the manual it will list tools needed

 

[Scott06]

Is the bellows sealed at the transom? If so, how did the bilge get loaded with lube oil?

As AD mentioned at one end of bellows is drive at other end is gimbal bearing there is a drain hole near gimbal that any gear oil or water that gets in there will leak into bilge. Conversely if the bilge gets really full of water it can also back fill the bellows

Is it an easy job ? If you have the tools and skills yes. Also a factory manual helps. If considering doing it your self get a manual read through it and determine if it is doable.

Other thing is it may be worth it to reseal the entire drive depending on age condition and previous work done. If water got in bellows can rust the input yoke causing this seal to leak.

I had an alpha drive prop shaft pick up fishing line last fall. By the time I got into it and found a pitted bearing I ended up doing most of the bearings and all the seals. Needed a few drive specific tools.

If you are a gear head and have rebuilt engines, trans, swapped rear end gears it’s no issue. If changing brake pads is the limit of your experience would think taking the drive somewhere and having them pressure test and do what ever resealing it needs is a good option

 

[gcarmich]

As AD mentioned at one end of bellows is drive at other end is gimbal bearing there is a drain hole near gimbal that any gear oil or water that gets in there will leak into bilge. Conversely if the bilge gets really full of water it can also back fill the bellows

Is it an easy job ? If you have the tools and skills yes. Also a factory manual helps. If considering doing it your self get a manual read through it and determine if it is doable.

Other thing is it may be worth it to reseal the entire drive depending on age condition and previous work done. If water got in bellows can rust the input yoke causing this seal to leak.

I had an alpha drive prop shaft pick up fishing line last fall. By the time I got into it and found a pitted bearing I ended up doing most of the bearings and all the seals. Needed a few drive specific tools.

If you are a gear head and have rebuilt engines, trans, swapped rear end gears it’s no issue. If changing brake pads is the limit of your experience would think taking the drive somewhere and having them pressure test and do what ever resealing it needs is a good option

Thanks! I re-did the heads on the engine last year - two valves had tuliped. I read through the manual and it looks straight forward. Also checked out a couple of videos. I feel confident I can do it. Looks like I will need "retainer nut wrench" tool, o-ring, and oil seal and some specific greases and lubricants. Still studying up on pretensions the nut. AD mentioned checking tolerance - are there specific that I should look for?

 

[dubs283]

Rolling torque is 3-7 lb/in for used bearings

Best practice is to use a 0-30 lb/in dial torque wrench following protocol outlined in the factory service manual

Ime that is the most critical part of the process

Don't skip the +/- offset on the gear/race upon reassembly

 

[gcarmich]

Rolling torque is 3-7 lb/in for used bearings

Best practice is to use a 0-30 lb/in dial torque wrench following protocol outlined in the factory service manual

Ime that is the most critical part of the process

Don't skip the +/- offset on the gear/race upon reassembly

Ok. I'll study up on that.
Will I need to disassemble bearing?

 

[dubs283]

Yes

As stated it's outlined in the fsm

Mercury actually knows how to repair their products with the proper parts and tools as described in their manuals

 

[Scott06]

Yes

As stated it's outlined in the fsm

Mercury actually knows how to repair their products with the proper parts and tools as described in their manuals

This is the truth always impressed with level of detail in their manuals, and they give complete transparency of what you need to do to service

 

[dubs283]

complete transparency of what you need to do to service

With hand drawn pictures, artiststry included from oem

 

[gcarmich]

With hand drawn pictures, artiststry included from oem

I have the seals and bearing kit on their way. I'm still confused why the bearings have to be removed but that's what the manual says. Next need is a dial in-lb torque wrench with the proper range - that an expensive tool for a 1 time use (I hope). I have a click in-lb torque wrench that has been verified but that doesn't seem to be the right tool (accuracy issues).

 

[Scott06]

I have the seals and bearing kit on their way. I'm still confused why the bearings have to be removed but that's what the manual says. Next need is a dial in-lb torque wrench with the proper range - that an expensive tool for a 1 time use (I hope). I have a click in-lb torque wrench that has been verified but that doesn't seem to be the right tool (accuracy issues).

The bearings are bigger than the ID of the seal so on the yoke the seal goes on first then the two bearings tightened down until you get the correct rolling torque.
I bought a beam type 0-75 in lb wrench for about $65 (McMaster Carr) when I changed rear end gears in my 65 Pontiac. When I did the upper on my alpha one I bought a dial type one that was maybe $150-200 And had a cert of accuracy that was better. They read the same …

just pay attention to the shims behind the bearings.if reusing the bearings keep the old shims and you will be ok. If you end up needing bearings you will need the shimming tools. I found them on ebay used for about half price. looked like the seller bought a complete set and used it once or twice …

 

[dubs283]

The bearings/races don't need to be removed from the gear, just need to remove the gear/bearing pack assy from the yoke shaft along with the tapered washer, seal carrier, spacer, o ring, washer and nut

You can gently rap on the gear end to unseat the bearing pack so upon reassembly the nut will "press" the bearings/races back together to the specified rolling torque. Small increments of nut tightening with checking of rolling torque until spec

Never used anything but a dial lb/in torque wrench to set the rolling torque so I have no say in other methods. I have overtorqued the bearing/race pack a couple times which simply requires disassembly and gently rapping on the gear end to unseat the bearing/race pack. Then reassemble and follow the rolling torque set procedure again

 

[gcarmich]

Do I need to take off the cover plates and remove the yoke and cam assembly before removing the U-joint assembly?

 

[dubs283]

No

But it will give you a chance to clean and inspect the entire upper driveshaft housing assy. The only other seals replacable aside from the yoke seal are the shift shaft seals and there's not often failure/need to replace them, everything else is o ring sealed. Also, going back together it'll be easier to verify the +/- offset alignment of the fwd/rev gears

 

[gcarmich]

No

But it will give you a chance to clean and inspect the entire upper driveshaft housing assy. The only other seals replacable aside from the yoke seal are the shift shaft seals and there's not often failure/need to replace them, everything else is o ring sealed. Also, going back together it'll be easier to verify the +/- offset alignment of the fwd/rev gears

The u-joint assembly isn't pulling out completely. The o-ring is visible but the unit won't pull out any further. I'm not sure how to get force on it to pull it out. Are there any tricks to getting it out?

 

[dubs283]

Heat around the housing/snout prior to removal has worked for me

Prior to applying heat re-seat the u joint/bearing/gear assy into the housing. It's real easy to offset the gear pack and have it bind during removal

 

[gcarmich]

Reseated the assembly and was able to remove it without heating! Thx. One of the races is slightly burnished - and there is some rust on the spliced end into the engine - are these concerns?

 

[Scott06]

Reseated the assembly and was able to remove it without heating! Thx. One of the races is slightly burnished - and there is some rust on the spliced end into the engine - are these concerns?

I wouldnt be concerned on either. Would look in the housing -if the aluminum casting is scored up or it is really loose with some play you are ok. If it is loose I have staked housings like this to create a raised area to tighten up the fit as a last resort