Force 120hp upper driveshaft bearing

[k_schutte]

Hello guys! So, long story short, my lower end fluid was a little low and my upper drive shaft bearing took a poop on me. I was lucky and nothing got damaged, it didn't "grenade" or anything like that, just seized up. I got the lower unit off and I got that retainer off as well as the outer race, cage and rollers of the old bearing. So, I just need to get the inner part of the old bearing off in order to put the new bearing on. Obviously, I need to remove the drive shaft to do so, how do I go about getting it out?


capture

#9 is what I need to replace. No one around here will touch a Force, apparently they're the outboard equivalent to the plague....

 

[Frank Acampora]

Re: Force 120hp upper driveshaft bearing

The pinion must be removed. It is on a locking taper, just like the flywheel so it will not be easy. You may need to make a tool or improvise.

Using a breaker bar and the correct sized socket. place the socket over the pinion nut. Now, pack the gearcase so the socket does not slip off the nut. Using something--I use an old prop hub that matches the drive shaft splines and a really long pipe wrench-- turn the driveshaft to break free the pinion nut.

After that is done, you again need to pack the gearcase and wedge some taper in between the packing to pop free the pinion gear.

Use a Dremel tool with a grinding disc to cut most of the way through the inner race. Then hammer in a wedge (cold chisel) and it will break and fall off the shaft.

Heat the new bearing over a 100 watt incandescent bulb for about 15 minutes and put the shaft into the freezer. The new bearing will slip over the shaft if you act quickly.

Torque the pinion nut to 85-90 foot pounds. (I think)

 

[k_schutte]

Re: Force 120hp upper driveshaft bearing

excuse my ignorance, what/were is the pinion nut. I am mechanically inclined but don't know much about lower units at all. I made the tool to remove the retainers (15/60) but.... I'm having a hard time visualizing what you're saying. :blue:

and while I did get the retainer off, I can't seem to get the spool assembly out. If that has to come out to do this...?

 

[jerryjerry05]

Re: Force 120hp upper driveshaft bearing

#11
Get a manual.Factory manual.

 

[Frank Acampora]

Re: Force 120hp upper driveshaft bearing

In the center of the pinion gear (top gear that drives the other two) there is a nut that tightens it to the locking taper on the shaft. However, If you didn't know this, I suspect that you are going to have a LOT of trouble. If you have a knowledgeable friend, ask for help. Two minds are better than one.

Yes, The spool assembly must be removed. You are looking at an almost complete tear-down of the lower unit to replace the bearing. The spool is sealed with two O-rings and is usually very tight. There are two threaded holes in it. You need to make a puller with a (block or a steering wheel puller) and some all-thread to get it out.

 

[kleary]

Re: Force 120hp upper driveshaft bearing

Similar issue. I had a small oil leak and traced it to a blowout on the shift shaft bellows seal. While the Lower Unit was off, I noticed that the top driveshaft bearing was very loose. I'm not up for a full bearing replacement at this time in the season. So . . . can I simply tighten the Retainer to reduce play in the bearing rollers? Or is it already bottomed on a shoulder somewhere? I'd try it myself, but I still have to spend the 1 hour+ to find some iron pipe and make a Retainer wrench! Thanks.

 

[Frank Acampora]

Re: Force 120hp upper driveshaft bearing

Not polite to hijack a thread but I will answer anyway:

The gears on that particular lower unit cause an UPWARD force when running. The bearing cup (outer ring) and retainer stop the upward movement and contain the force.There is nothing to stop the driveshaft and pinion from dropping slightly, especially when the water pump is off. There are shims under the cup (outer ring) to set gear backlash and the retainer should be tight already.

Bottom line: The bearing will feel loos when you wiggle the drive shaft with the water pump off. If you push down and turn the drive shaft you will either feel or hear the gears making noise because backlash is too tight. If you pull up and turn the drive shaft, the gears should mesh silky smooth.