lower unit driveshaft bearing

[jamesp59]

I am rebuilding a lower unit on a 1985 90hp Merc. I been trying to figure out which way the driveshaft bearing goes. I heard the tapered bearing has to go upside down, so this means the bearing would go on the driveshaft facing up then the race would sit ontop of that inside the LU? So would it go in the Lu in this order? shims,driveshaft with bearing then the race facing down then water pump? PO already had the LU off the motor so I dont really know if it had a push pin, but it didnt come with one. Any help would really help me I dont want to put this in the wrong way and destroy what Im trying to fix. Thank Parker

 

[oldman570]

Re: lower unit driveshaft bearing

According to 1Manual .com the bearing goes on as you think, with the shims first, then the bearing, then the race pressed in the houseing.
Oldman570

 

[gwukena]

Re: lower unit driveshaft bearing

There are also shims between bearing race and water pump base.

 

[jamesp59]

Re: lower unit driveshaft bearing

I forgot to tell you guys that it has the straight spline gears also. What holds the drive shaft bearing in, the water pump? There is no clip that goes on the drive shaft, is that right? Its been really hard trying to find the correct way to assamble this thing. Is there any diagrams or pics that show the correct way to assamble this LU.
OLDMAN570= I tryed that web page and it didnt open. Do's it show a diagram of this assambly process. If it do's can you post it on here.
Thanks for the Help
Parker

 

[carholme]

Re: lower unit driveshaft bearing

What is the s/n of your engine?

Gerry

 

[gwukena]

Re: lower unit driveshaft bearing

Best bet is to get a factory manual for doing lu work. Why was the unit disassembled, only for leaking seals, or were hard components replaced (i:e: bearings/gears)? If hard parts were replaced, you're going to have to set up from square 1 and best to take to dealer as special tools required. The water pump base holds bearing in and is shimmed to preload bearing. There are also a thick spacer and shims that go under bearing and housing to set pinion gear depth/backlash, for your sake I hope the shims from upper and lower side of bearing haven't been mixed up. Crowley marine has parts breakdown diagram for that unit.

 

[jamesp59]

Re: lower unit driveshaft bearing

ser# A176214

 

[jamesp59]

Re: lower unit driveshaft bearing

I replaced all the bearings and seals. I have a manual but it shows the assambly in this order,spacer, shims, bearing race, bearing on the drive shaft with the smallest part of the bearing facing down to join togather with race, and last the water pump housing. This is the way I put it togater now I'm wondering iits wrong from what I read around in the forums. This is the way My book shows it,but I also got it on line for a few bucks,and its not for just my year but several other years also. Thanks
Parker

 

[carholme]

Re: lower unit driveshaft bearing

Here is the parts listiing for your s/n:

http://www.crowleymarine.com/mercury-outboard/278.cfm

OEM Service Manual P/N: 90-86134--4

If you can't find a copy of the OEM manual, here is a condensed version of the Clymer manual which will help you out:

http://web.ebscohost.com/serrc/pdf?...1-8ad5-844bba43c564@sessionmgr13&vid=4&hid=21

Download it as soon as you can as the link does not stay open for long.

Gerry

 

[jamesp59]

Re: lower unit driveshaft bearing

Gerry,
I can't get that link for the manual to open,do's it show the correct way to assamble the drive shaft bearing? I opened the parts listing and went to drive shaft diagram and this is how my book shows it going togather, Is this right or is this a generic diagram?
Parker

 

[carholme]

Re: lower unit driveshaft bearing

parker;

You have to wait 20/30 seconds for the link to open as it is a 3.7Mb file. Just give it some time and it will open and then you can save it to your computer with the "Save As" button at the top LH of the header.

The parts list is specific to your s/n as is the service manual.

Gerry

 

[gwukena]

Re: lower unit driveshaft bearing

I replaced all the bearings and seals. I have a manual but it shows the assambly in this order,spacer, shims, bearing race, bearing on the drive shaft with the smallest part of the bearing facing down to join togather with race, and last the water pump housing. This is the way I put it togater now I'm wondering iits wrong from what I read around in the forums. This is the way My book shows it,but I also got it on line for a few bucks,and its not for just my year but several other years also. Thanks
Parker

Here is a pic from my 83 115 that I just pulled apart, same lower unit as yours. It probably wouldn't make a difference which way bearing is installed, just becomes a pain in the arse for set up if cup installed into housing first. A friend of mine (dealer who cut his teeth on inlines) had this apart about 15 years ago, possible he may have turned bearing around for easier set up, I will contact him and see if he remembers this being a dealer trick,.

 

[jamesp59]

Re: lower unit driveshaft bearing

gwukena,
WAs there shims between the race and water pump on yours? And do you have straight teeth on your gears also?
Thanks
Parker

 

[gwukena]

Re: lower unit driveshaft bearing

gwukena,
WAs there shims between the race and water pump on yours? And do you have straight teeth on your gears also?
Thanks
Parker

Yes, shims between water pump and race, Straight cut gears also. After further inspection, looks like orientation does matter. It looks like spacer ring has to seat against cone outer race as there is a protrusion of a few thou of the cone's built in spacer ring. This would mean cup has to be installed on top of bearing. So installation would go like this, shims, spacer, driveshaft assembly with wide part of cone to bottom, cup on top, shims, water pump base. See pics below.

 

[carholme]

Re: lower unit driveshaft bearing

Parker;

Are these parts, brg, shims and spacer which you are trying to install, ones which you removed or are these new parts? The confusion seems to be the shim set and where it goes but it is only used with the older style ball bearing. In your first post, you refer to tapered brg., so I presume that you have the new style which does not require the shim set, just the spacer as per the photo which gwukena provided. If you look at the manual again on page 13/14 at figure M14-52, there is a note which explains this. The peelable shims are only used for the ball brg to adjust the pinch when the waterpump housing is torqued down.

Gerry

 

[carholme]

Re: lower unit driveshaft bearing

gwukena;

Sorry, I stepped on you. You guys seem to have it in hand.

Gerry

 

[gwukena]

Re: lower unit driveshaft bearing

Parker;

Are these parts, brg, shims and spacer which you are trying to install, ones which you removed or are these new parts? The confusion seems to be the shim set and where it goes but it is only used with the older style ball bearing. In your first post, you refer to tapered brg., so I presume that you have the new style which does not require the shim set, just the spacer as per the photo which gwukena provided. If you look at the manual again on page 13/14 at figure M14-52, there is a note which explains this. The peelable shims are only used for the ball brg to adjust the pinch when the waterpump housing is torqued down.

Gerry

He's got straight cut gears, no retainer on upper driveshaft, shims between bearing and gearcase set pinion depth, shims between water pump housing and bearing control bearing preload

 

[gwukena]

Re: lower unit driveshaft bearing

gwukena;

Sorry, I stepped on you. You guys seem to have it in hand.

Gerry

No problem, the manual is very vague when it comes to these models, it's not until you get one apart that you start to scratch your head, life was so much easier with a straight roller bearing and preload pin

 

[jamesp59]

Re: lower unit driveshaft bearing

Gwukena,
Yes this is my set up. I had the driveshaft bearing upside down. The manual isnt very helpful with this model as you said. Now I have to flip the bear around. Is there anyway to remove the bearing from driveshaft with breaking it? Thanks for all your help I was lost on this step and would of put it togather wrong if you didnt help me. Now to remove the bearing and start over. Thanks Again for your help.
Parker

 

[gwukena]

Re: lower unit driveshaft bearing

Gwukena,
Yes this is my set up. I had the driveshaft bearing upside down. The manual isnt very helpful with this model as you said. Now I have to flip the bear around. Is there anyway to remove the bearing from driveshaft with breaking it? Thanks for all your help I was lost on this step and would of put it togather wrong if you didnt help me. Now to remove the bearing and start over. Thanks Again for your help.
Parker

I assume you mean not break it Shouldn't take too much tonnage to move that bearing, but you're going to need a press. I think the way you have bearing current installed inverted, there should be enough meat on the bearing inner race to get off using a press and bearing knife. Od of shoulder that bearing seats against 1.495", width of inner race of bearing cone 1.510" plus or minus a couple of thou. Even a short piece of pipe about 1.5" diamater that fits over shoulder to bearing inner race should work. A shot from a CO2 fire extinguisher should cool shaft enough to allow bearing to move. When reinstalling put shaft in deep freeze for a few hours, and warm bearing to about 275 deg F. Bearing should slip right on.