How to remove propeller shaft?

[DunbarLtd]

1988 Force 85hp 856X8A

Well its bad news...... last time out about halfway across the lake I heard a nasty sound coming from the lower unit enough to stall the motor. Used the trolling motor to get back to the docks. I had just changed the oil 2 weeks ago too with Quicksilver 90wt.


Anyways to get right to the point, I have removed the spool and the reverse gear off the shaft. I looked in with a flashlight and the forward gear has just completely shredded its teeth. There was also damage to the pinion gear (drive shaft gear) as well. The reverse gear has one tiny chip on only one tooth from what i saw. The needle bearing looks fine.

I ran the motor in reverse gear no problem, but when i tried to put it in forward a couple times the nastiest grinding sound was heard and it would stall the motor. So after only two attempts i stopped and just used the tolling motor to get back home.

Would love to know why that happened???

I found a replacement gear assembly with bearing for actually a fair price. Ive read that its recommended to just buy a used lower unit rather than try to repair these things because of cost. Well since I found a good deal on the gears I will do this repair.

I removed the pivot pin. Now the next step I believe is to pull the propeller shaft but it seems like its in there pretty good. Shouldnt it just slide right out because in my service manual it just says pull the shaft out. It says do this while the reverse gear is still on but i got a hold of it and removed the reverse gear first. Thats when i noticed the forward gear teeth ground off.

Anyways any helpful tips would be appreciated. Thanks.

 

[DunbarLtd]

I pulled the shift rod up (Shifted gear into reverse) and shaft came out. I guess the pivot pin clip was still holding onto the shift rod. Once I lifted it, it let go and the shaft came right out.

Next step is to remove drive shaft and then forward gear assembly which should just slide right out after i get the drive shaft off. Which looks fairly straightforward. I will make sure I do not lose the shim spacer on the forward gear.

Anyone know what size drive shaft spline socket to use on the top of the drive shaft? This will be needed to torque the pinion nut to 85ft lbs on reassembly. I could just get a pipe wrench on the shaft to spin it off but Id like to find the correct socket so i can properly torque it later.

Still looking for any tips on reassembly. For instance, I will be removing the drive shaft. The manual states that I will be using a new crush ring. Is this true?

 

[jerryjerry05]

T-7848 is the part # for the drive shaft splines.
Finding it might be fun!!
Try Mercury

I think the nut on the other end is 3/4"

Yes on the new crush ring.

Get the factory manual for reassembly.
Cover the steps fairly well.

The new parts come with the race for the front gear?

 

[DunbarLtd]

T-7848 is the part # for the drive shaft splines.
Finding it might be fun!!
Try Mercury

I think the nut on the other end is 3/4"

Yes on the new crush ring.

Get the factory manual for reassembly.
Cover the steps fairly well.

The new parts come with the race for the front gear?

I wouldnt attempt this without a factory manual so Ive been reading all the steps. The most important i believe in this repair is getting the clearances right and making sure it is shimmed properly. I have read the charts. Found the marking on my lower unit so i know where i need to be with those (shim) measurements.

I havent ordered parts yet. But the part I found did not come with a new race. It is off a used lower unit. There are clear pictures and it appears to be in great condition.

I will likely have to reshim for proper clearances between forward gear and pinion. There was already a single shim on the forward gear. Im hoping I can reuse it and not have to reshim there but its likely i may have to if I want to set the prop shaft correctly.

Is there a way to test for these clearances with out the special tool recommended in the manual? The half moon shaped tool with the collar that sits inside the housing so you can get a feeler gauge between it and the bottom of the pinion gear.

Thats the only part where I may run into difficulty. I dont want to just slap the parts back in and hope for the best. It may be short lived if I dont get the clearances, gear lash, etc right. Its not as quite complicated as differential gears but i assume its the same idea. You want the pinion to ride on the drive gears centered?

There is no spec on rotational preload so looks like as long as the feeler gauge measurement checks out then thats all thats needed?

Also when setting the new pinion gear to check for initial clearance do i use a new crush ring and then test for the proper clearance. I think in the manual it says to use a ,050" shim to start with and then do the math to see what the final shim needs to be. It doesnt mention using a new crush ring in that process.

So I assume I have to waste a crush ring if I need to take it back out and reshim?

 

[jerryjerry05]

What service manual do you have?
Sounds like an older one??
I have a service manual put out in 8/89 12-13pages.
This manual shows how to shim without any tools.
Send me a pm with your e-mail and I'll send it to you.

If your housing has a mark near the end of the tail of the shift shaft cover?
Should say ? " FORWARD GEAR" then a letter A-I or a number 0-9
Then this book should help do the job without a shim tool.
And I think it's done with one crush ring

I'll check back about 3 pm. and send it to you if I get a PM
I usually only get on here in the mornings.

 

[DunbarLtd]

Thank you for the shimming instructions JerryJerry.

 

[DunbarLtd]

So I noticed the inside of the housing around the forward gear teeth has some pitting. Looks like the metal shaving were ground against it.

Being as nothing in that area is actually spinning and touching the housing and its only pitted could I just sand down any sharp edges and leave it be? I was also thinking maybe jb welding the pitted spots and sanding smooth?

Also when removing the drive shaft pinion, did you have any methods you preferred?

 

[jerryjerry05]

Pics?
The problem with JB is once you fill the holes.
The lower, during use, heats up and cools down.
The expansion and contraction can cause the JB to fall out.
Then you got junk in the lower.

 

[DunbarLtd]

Ok I was able to get the pinion gear off and pulled the drive shaft out. Inspected the needle bearing and the tapered roller bearing. I noticed the tapered roller bearing isnt running too smooth. Sorta groans when i spin the shaft by hand. I noticed a little corrosion on some of the rollers and a little bit on the race as well. I know what a good bearing should sound like and its definitely not sounding like it should.

So I would like to replace it if possible. I found a new one on bid site. I have the tools to press it on and off.

The only thing Im not sure about and cant find any info on is how far to press it onto the drive shaft??? Do I just press it on until it bottoms out because there isnt any spec in the book. Just says install it.

Also is it normal for that tapered bearing race to come out easily? I was able to just pull it out once i pulled the shaft.

 

[jerryjerry05]

It shouldn't come out easily.
Sounds like it's time to replace??
Sent you the page covering the r@r of the bearing.
Since it's out?? it should be easy to replace.

 

[DunbarLtd]

It shouldn't come out easily.
Sounds like it's time to replace??
Sent you the page covering the r@r of the bearing.
Since it's out?? it should be easy to replace.

Thanks for the emails but its not the lower needle bearing. I included a pic of the bearing i need to replace.

My issue is how do i get it pressed on exactly where it needs to? Feeler gauges slid in between the top of the bearing and that collar or is it tapered there just before the collar and stops where it should? I havent taken it off yet so i cant tell if theres a slight taper thatll stop the bearing. .

And I found all the shim instructions in my manual. They have all the same pages you sent me. I must have overlooked them. The forward and reverse gears I bought do not have a tag so i will most likely need the tool. Ive seen one on a bid site i may pick up.

However in the manual is also says if one can not get a hold of the tool to just put the shims back in there all call it a day.

Mine has 4 shims under this top bearing race, which is the picture i included. They are all the same size shims that came with my new pinion gear. I dont see why I cant just add all the new shims in there and itll be good???

Hopefully that clears up any confusion. Thanks for the help.

tldr; How far do i press on the top drive shaft roller bearing????

 

[Nordin]

Dunbart you should press the roller bearing as far as you (it stops) could to the collar.
The shiming is done under the collar for the pinion gear to the forward/reverse gear.

For your own feeling and to be sure, measure the distance between the roller bearing (upper edge/part) and collar where the shim suppose to be placed before you pull it.
Press the new to same distance, I think it will be all way to the collar.

 

[jerryjerry05]

Looks like the lower end of the drive shaft has an edge built up.Pic doesn't show the whole shaft?
Add a pic with the new bearing on the end of the shaft.
Possibly the bearing can be put on the end of the shaft and inserted into the housing.
When the bearing came out, did it fall all the way through or did it come out from the top?
Is there a lip at the bottom of the hole?

 

[DunbarLtd]

I havent removed the bearing off the shaft. Its still pressed on. This is what you see in the picture i uploaded. In this diagram #77 is the bearing but as you can tell it does not show much. The manual doesnt mention anything about how FAR to press on the bearing. It shows a picture of a bearing splitter tool and says you can use a shop press to remove/install the bearings. Doesnt give any mentions of how far the bearing is pressed on.

Im assuming there will be a slight taper on the shaft and itll press up against that taper and stop. What you see in my picture is what it looked like when i removed the shaft.

The taper on the bearing faces DOWN. Which is confusing in this diagram as the drawing does not clearly indicate this. But in my picture i added in my previous comment the taper rollers will sit facing down onto the race. Im not sure if that race is actually hard pressed into the housing or not. Since the shims sit underneath this race I dont see it being practical to have this race pressed in, take measurements to make sure shim is correct, and then if they are not correct - you have to then extract the race with a press again. Which would ultimately damage the shims if you think about it.

This seems like a very difficult process if that were the case. Especially when they mass produced these motors. Im pretty sure the race for the bearing slides in and out. Now mind you, its a pretty tight fit in there but with some persuasion via the fingers, it slides out ok. I have not received the new bearing yet but i will see how tight of a fit it is when it shows up and let you know.

I think the two piece shaft bearing faces up. Mine is a one piece shaft. So in my previous picture the shiny part of the shaft goes up into the powerhead. The lower part of the shaft has varying diameters along the shaft to accommodate the needle bearing at the bottom.

The only thing that is not very clear is whether there is a big enough taper and the bearing will simply hit this taper and stop. Im assuming this is the case and I think if i heat up the bearing and put the shaft in the freezer the bearing should slide all the way down to its seat position without having to press it on. Thats how interpreted a comment I found that Frank A made to someone with a similar issue.

Thanks for the response Jerry.

 

[DunbarLtd]

Dunbart you should press the roller bearing as far as you (it stops) could to the collar.
The shiming is done under the collar for the pinion gear to the forward/reverse gear.

For your own feeling and to be sure, measure the distance between the roller bearing (upper edge/part) and collar where the shim suppose to be placed before you pull it.
Press the new to same distance, I think it will be all way to the collar.

Thanks Nordin. It sounds like the bearing should just stop when it goes far enough. I guess Ill also measure before removing the bearing.

The shims actually go into the housing first. There is a small lip inside they rest on. Then you drop or press in the bearing race. Then drop the shaft in until the bearing seats in the race.The tapered roller bearing (part #77) is not visible in the diagram. What you see is the race, basically.

Theres a crush ring (part #50) that sits on top on the bearing that is crushed down when you tighten the water pump bolts. This ring will secure the bearing and sustain shaft depth so the pinion will keep its lash with the drive gears. There is a small collar (part #53) that protrudes from the underside of the gear housing cover that will push against this crush ring.

I think I have the information I need now. Thank you.

 

[DunbarLtd]

Looks like the lower end of the drive shaft has an edge built up.Pic doesn't show the whole shaft?
Add a pic with the new bearing on the end of the shaft.
Possibly the bearing can be put on the end of the shaft and inserted into the housing.
When the bearing came out, did it fall all the way through or did it come out from the top?
Is there a lip at the bottom of the hole?

Yes there is a lip when looking in from the top. That lip is where the shims were sitting when i pulled the outer race out. So the bearing assembly sits on top of the shim pack.

Evidently the outer race had become detached from the roller bearing. Reason I suspect this is the new bearing just arrived today and it is entirely all one piece. Just like the diagram shows. I can not remove the outer race like i could with the old one.

When i pulled the shaft it came right out without any resistance whatsoever. The bearing still pressed on the shaft. I looked into the hole and noticed the outer race sitting on the lip and worked it out with my fingers.

Now Im wondering when i drop the shaft in with the new bearing how tight of a fit it will be.

When doing the shim test fit, it just says to install the shaft. Doesnt mention any tools necessary. Then when you are done measuring to wrap a towel around the spline and use a wrench and some type of slide tool to bang the shaft back out. There is an illustration for that. So Im assuming its gonna be a super tight fit when installing the shaft.

Any idea whats the best way to approach this?

 

[DunbarLtd]

Here is the shaft after bearing removal. Bearing was on the right side of the collar. It sure doesnt look like there is any type of taper before that collar. Im wondering if the bearing moved when it separated and rode down the shaft which caused the gears to be misaligned???

I have found nothing anywhere that shows where this bearing should ride on the shaft. Im not convinced it should stop short of the collar. Theres no taper there. I bet it snugs up right close to it and the old one moved somehow. But Im just guessing. I wish there were more information on this problem.

 

[Nordin]

Dunbart the bearing should go against the collar.
It has press fitting and maybe your surface at the drive shaft is a bit worn.
Check with the new bearing and try to slide the bearing on the drive shaft,
It should not be possible to do it by hand.

You assemble it by cooling the drive shaft down in a freezer and heat the bearing.
Be careful not to heat the bearing to much, just make it a bit warm.
Then you should be able to just slide the bearing to the drive shaft and all the way to stop at the collar.

 

[jerryjerry05]

The bearing should stop where it's stops.

In a perfect world???? the freeze and heat method can work(maybe)??
My 20ton press, I had to lift it up on blocks to have clearance for the end of the shaft.
The removal tool works good for reassembly.
Just turn it over.

 

[DunbarLtd]

Alright I will try the heat and freeze method and see what happens.

The new bearing is definitely a tight fit on the shaft. Its possible it is worn where it seats and the bearing moved but Ive been thinking about it and I cant seem to figure out how in the world it could move on the shaft?

Its sandwiched between the lip in the bottom of the bore and the crush ring from above so i dont believe the bearing moved at all. Im guessing the shaft was forced upwards somehow and the bearing slipped.

Might have something to do with the stripped forward gear?? When I changed the oil I made sure it was full and let it sit for 30 minutes several times so i dont think the bearing dried up and overheated but anything is possible i guess. Also its 30 years old and most likely had the original bearing in it so its possible it just wore out and broke.

Anyways, thanks for all the helps guys. Hopefully I wont run into any more snags and be back on the water soon.