Replacing bearings in Nissan NS5B lower unit

Water got in my lower unit and made a mess of things. Lots of rust and corrosion. 1992NS5B, 20" shaft. Power head was in great shape (20 hours run time), and I hated to discard the motor because of a bad LU. Local shops wont work on small portables unless Honda or Yamaha. Guess the last time I changed the water pump I reused the old oil plug gaskets which may have leaked and the big o ring in front of the prop failed some where along the line.

I stripped the LU and removed everything except one bearing at the interior end of the prop shaft. This has been a pain and I cant budge it with penetrating oil and a slide hammer bearing puller. This is the only thing left to remove. I removed the gear in front of it easily. I managed to clean up the gears and hardware to like new, rust free condition by soaking in evapo rust. I plan to replace all bearings, gaskets and seals. Anybody have any idea how to remove this bearing? And how best to set the new ones? I have factory repair manual and parts catalog.

I am suprised you can still get parts for these things and they are reasonable.

Re: Replacing bearings in Nissan NS5B lower unit

The front bearing can be tough to extract, especially if there was/is some corrosion to the aluminum housing (making it swell a little). The first question would be whether that bearing even needs to come out. If it's in good shape, and you aren't installing new gears, you can leave it alone. The "factory way" to remove it is with an internal type gear puller... But... we have been able to pop a few out by filling the internal cavity with heavy (#2 or better, #3 grease, and then placing the tip of the gear (and the prop shaft with push rod) just barely into the bearing, and then rapping the end of the prop shaft (swiftly) with a heavy mallet. The hydraulic force can pop the bearing out. Has been done on automotive clutch pilot bearings all the time, "back in the day". The LU gasket set is 369873210M LOWER UNIT GASKET SET $21.23, available from any dealer, including me. The most overlooked seals are the shifter bushing o-rings. If you aren't sure about the quality of the bearing and gear tooth faces, the gear case is available: 369S600003 GEAR CASE ASSY $122.60, and the whole LU is also still available: 369S873023 LOWER UNIT ASSY L $546.58

Re: Replacing bearings in Nissan NS5B lower unit

Thanks Paul;

Believe me, there was some serious corrosion in there, when I open it up it looked like the exterior of the Hunley (I worked on that project for awhile). So I thought it would be a real challenge to restore this as well. The gears all look very good after cleaning in Evapo Rust, no pits or wear. I bought this motor new in 1992, and as a kicker for my sailboat, it only has 10 hours or so on it, so wear on anything is minimal. It sits on the back of my boat in some pretty extreme hot weather so every thing made of plastic or rubber takes a beating (3 water pumps over the years), I just neglected the o-rings and oil plug gaskets, hence the oil departure and water intrusion.

Now I am heating the stripped down lower unit in the oven (200F) and froze the blind hole bearing extractor in the freezer, will apply ice chips onthe bearing and quickly try to pop it out with the slide hammer puller. This has worked for me on motorcycle/snowmobile engines in the past (main bearings). If I am successful, I will need parts...what is included with the three kits you mention and how can I contact you for parts?

Re: Replacing bearings in Nissan NS5B lower unit

No luck there, outer race must really be bonded by dissimilar metal corrosion product. I will soak in PB Blaster a couple of days then try the grease thing you suggested. Let me know on the parts question I had for you. Thanks.

Re: Replacing bearings in Nissan NS5B lower unit

I am impatient and went to the local auto parts store and got some CRC Freeze Off. I was able to chill the bearing locally with the spray enough to get the bearing out with the slide hammer puller. This stuff is great and will forever be in my shop. Thanks again, if you could send me contact for parts I am ready to put her back together.

Re: Replacing bearings in Nissan NS5B lower unit

pepper h. said:

I am impatient and went to the local auto parts store and got some CRC Freeze Off. I was able to chill the bearing locally with the spray enough to get the bearing out with the slide hammer puller. This stuff is great and will forever be in my shop. Thanks again, if you could send me contact for parts I am ready to put her back together.

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That's great news! Occasionally we change the housing because of the problem you had. Of course, as a shop that has to charge for labor by the hour, the price of the gear case represents less than 2 hours of work. You can call 716-877-8221 M-F, 9-7 Eastern, and ask for Paul, or just drop me an email at the office paul@obersheimersails.com if you need anything.