Replacing bearing on bevel pinion - lower unit

[adrock430]

Hi,
I have a leak on my 1988 force 50 hp, 507x8c, so I disassembled it. Found that the bearing on the bevel pinion is bent a bit and not rolling perfectly. Searching for parts, I find the full assembly, but not just the bearing. Can this bearing be replaced w/o buying the full assembly? Anyone know the p/n of the bearing?
Thanks! Adam

 

[Nordin]

Re: Replacing bearing on bevel pinion - lower unit

The pinion and bearing are sold as one unit from the OB partsstores, but I think you can buy the bearing from a machinestore (that sells bearings). Check for the typnumber. It is LM xxxxx something (can not remember exactly)
I have done it here in Sweden Europe but the bearing are two parts, the rollerbearing and the outer race They are matched parts.
Both SKF and Timken has it.

 

[Frank Acampora]

Re: Replacing bearing on bevel pinion - lower unit

You can buy the bearing at a bearing supply store. The outer race --or cup-- will have the number stamped in the thicker side. The inner bearing and race --cone-- will have the number stamped on the race where it is against the gear.

It is a heavy interference fit and will require a lot of effort to remove. Depending upon the lower unit, there may also be a shim under it. If there is a shim, you must be careful to not damage it because they are not available, even from the bearing supplier.

If you are succesful in removing the bearing and buying a new one the following procedure works best for installing the new bearing: Take the pinion and put it into your freezer for at least ten minutes. Take the bearing and place it on a lit 100 watt incandescent bulb, again for at least ten minutes. Remove the pinion from the freezer and using a leather glove quickly take the bearing and slide it onto the pinion till it bottoms.

The 100 watt bulb heats the bearing enough to expand it sufficiently to have clearance without overheating it while freezing the pinion will shrink it. The combination of the two forces will allow easy installation.

While you are at it, you can buy ( for about 7 bucks) a caged roller bearing to replace the bushing at the top of the lower unit under the water pump. Part number INA SCH1016 8 or SCH1016 B.

Simply drive the bushing out and carefully drive in the new bearing. You will need to replace the seal.

 

[adrock430]

Re: Replacing bearing on bevel pinion - lower unit

Thank you for the replies. I see the p/n of the race, didn't know if there are a variety of inside diameters that the race could correspond to. So you're saying I can figure out the bearing from the race? Removing the bearing is a whole another issue tho!!

I'm waiting for the seal above the needle bearing to come in, so I may as well replace that. It can be driven in from above, correct?
Thanks! Adam

 

[Frank Acampora]

Re: Replacing bearing on bevel pinion - lower unit



Yes. That is a straight sided hole as shown in the third photo. The old bushing can be driven out downward and the new roller bearing can be driven in from the top or you can go the other way.. BE CERTAIN to use a correct sized tool when driving it in and DONT get too aggressive with the hammer. You can bend the outer shell and jam the rollers inside the bearing. The new seal can also be simply driven back into its seat with care.

The pinion bearings do come in a number of sizes and the best way to buy one is off the numbers stamped into them. HOWEVER: ALL bearings are standardised and if you bring the complete bearing/pinion assembly to the bearing supplier, they can measure the pinion hub and give you the correct one.

I had cut down the length of the bushingbefore I investigated buying the bearing. This bearing is the middle of three different lengths.

AS I said above, getting the bearing off the pinion will not be an easy job unless you have specialzed bearing pullers, but it can be done. Typically, when I do it, I wedge something under the cage and rollers . This does destroy the cage but will usually get me enough room under the bearing race to pull it off. Just don't expect to do it in 10 minutes.

If I had an extra pinion/bearing assembly, I would offer it to you----but unfortunately I don't.

You can see the comparison between the stock bushing and the roller bearing. I also included a comparison of a 50 HP pinion and a 25 horsepower pinion. You can see that the hub is the same size even though the bearings are different and the splined hole for the driveshaft is different.

 

[adrock430]

Re: Replacing bearing on bevel pinion - lower unit

Very nice, thank you for the photos. I assume I'll get a performance boost from the needle bearing as well.

Thank you for the kind offer on the assembly, there's a guy on ebay I'm haggling with selling one pretty cheap. Either way, I'll be replacing the bearing on the bad one. I'll check in when I do. Thank you!!!