1980 Mainship MK1 bulkhead mounted bearing size

[Dwk]

I want to add a zerk extension hose to the aft support bearing for greasing and looking for any bearing info Mainship used for 1980 34 MK1. Ours must have been put in backwards since the zerk fitting to grease is AFT of the bulkhead, under the water tank(that's right!) under the tank. You can imagine what a PIA this is to service without a zerk extension hose.

[jleonard]

Torrington/Fafnir RCJC 1 3/8 Assuming you have a 1 3/8 diameter prop shaft.
If different diameter, then it's RCJC (blank).

That company is out of business, however any industrial supplier can cross reference that number to a current manufactured bearing of that style.
Yes the bearing is installed correctly or at least that's what Mainship thought.
You could move it to the forward side of the bulkhead when you do the new one.
(The 1978 models had the bearing on the forward side of the bulkhead. I was able to change mine without removing the prop shaft. I could slide the shaft back far enough to make the change)

TIP The bearing inner race has a set screw (maybe 2 180 deg apart) that secures the race to the shaft.
Remove that first or you'll never get it to budge.

Hope this helps.

[boomerang]

Jay, you're a definite asset to the forum & especially the classic Mainship community. I was talking to Dave this morning about his bearing issue and forgot to mention to him that you would know which bearing he would need if his was bad. I can imagine you were thought of as a rock star back in the day when you were an owner. And while I have you on the line, I want to take the time to sincerely thank you for helping me find the source of the oil leak that appeared on our Perkins last summer. I was thinking seals but I just couldn't trace down the exact source. I googled it and a it lead me to a post you made about the starboard forward engine mount fasteners being drilled into the oil passage. I inspected the mount underneath and it was wet. I pulled the studs one at a time,resealed with Permatex #2 and after a couple of cruises ,the bilge is oil free. I believe that lemon has been squeezed!
Viva La Internet & Jay Leonard.
Thanks again.
Now lets get David Kimmel going!

[syjos]

We had an 81 Mainship in the 90's.

The bearing was frozen to the shaft when we bought it. Disconnected the coupling and unbolted the bearing from bulkhead and slid the shaft back to make access to the bearing easier. Tried undoing the set screw but no luck. Cut the bearing off and replaced it with a split bearing to make future access easier. Installed the bearing forward of the bulkhead.

The existing bearing is gimbaled to allow for the angle of the shaft to the perpendicular bulkhead. I think they are called angular bearings or angular contact bearings.

When installing a new bearing with different bolt pattern to the previous bearing, make sure you compensate for shaft drop. Our Mainship had a bronze shaft which was not as ridgid as a SS shaft and sagged without the bearing.

If your shaft has been replaced with a SS shaft, an intermediate bearing may not be necessary. Check with a prop shop or Google to see what the mid support requirements are for a shaft with your diameter.

[jleonard]

Originally Posted by syjos

We had an 81 Mainship in the 90's.

If your shaft has been replaced with a SS shaft, an intermediate bearing may not be necessary. Check with a prop shop or Google to see what the mid support requirements are for a shaft with your diameter.

In THEORY it may not need the bearing, but in application it does IMO.

I tried eliminating the bearing but as I was tightening the prop nuts I could feel and see the shaft flexing quite a bit. It was a 1 1/2 inch dia Aquamet 22 (stainless) shaft.
So I put the bearing back in.

[hytedin]

When I had my 1975 Mk1 I purchased the replacement bearing from Grainger supply, had it milled at the shop so it would slide on (I think a few thousandths), then relocated to the other side of the bulkhead for service and future in-water replacement—no need to back the shaft all the way out.

[KenM]

Odd, my '84 MKIII has an extension "tube" on the bulkhead bearing that makes re greasing easy from the cockpit access. can't see down there, so I wonder what they did years ago?

[Jeff F]

Mine is on the back of the bulkhead. It's possible to get a grease gun in there, but not easy. I too wondered why it was on the back.

[jleonard]

In the original model Is the generator sat over the bearing so it was impossible to get at. I'm sure that's why they moved it to the aft side of the bulkhead.

I was able to cut an access hole in the floor to be able to get to it. Covered the hole with lexan so I could do a visual from time to time.
I removed the grease fitting, added a hose and an automatic grease cup

[Themrbobcat]

Adding a zerk fitting extension hose is a one time easy fix. We did it often in the industrial areas I worked. Keep it simple - Keep it safe .

Putting in multiple hoses off a manifold was done quite regularly.

[Seanair]

I have a 1978 MS I, the bearing on mine was always on the forward side of the bulkhead. Below is a picture of the new one I installed. I dont have the model number off hand but I'm sure I got it from Jay!

[MakinDo]

Does anyone have any tips for removing a shaft that is stuck in the mid ship bearing ?

[boomerang]

Clean the shaft with a wire brush and emery paper so theres no rust or burrs and it should slop through easily. As mentioned, make sure all of the set screws in the bearing are loose/removed. A sot of WD40 on the shaft will help ,too. It went on when the shaft was clean, thats how it has to come off.

[jleonard]

Alternate method is to use a cut off wheel on a disc grinder and split the bearing and housing.

[MakinDo]

Thanks. No luck yet. I sprayed with wd40 and cleaned it and it wont budge.

[jleonard]

Originally Posted by MakinDo

Thanks. No luck yet. I sprayed with wd40 and cleaned it and it wont budge.

When I replaced my first one ( with the boat in the water) we had to beat the bearing up the shaft with a 5 lb hammer and brass rods.
A friend of mine cut his in half with an angle grinder.
You can’t be gentle sometimes.

[Dwk]

Originally Posted by MakinDo

Thanks. No luck yet. I sprayed with wd40 and cleaned it and it wont budge.

Any progress removing the shaft?

[MakinDo]

I am half way done with cutting the coupler in half. After that i have to bang the shaft out of the mid way bearing.

[MakinDo]

Update. I was able to cut the coupler off the shaft. Cut completely through on the key side and made a notch about half way through on the back side. The coupler slowly came off after i drove it open with a wedge.

The shaft is almost out of the boat. The final 5 inches seems to be stuck in the midship bearing. It was slow going at first but then about 36 inches went sorta quick. Any tips on the final 5 inches? I dont see an option to cut the bearing off without damaging the shaft.

[Comodave]

Maybe put the prop nuts back on the end so you don’t damage the threads. Then try driving the shaft back in a bit while lubricating then heck out of it. Then try pulling it again. Maybe twisting it while pulling it.