Replacing A Cutlass Bearing (Photo Heavy)

[sailsdean]

cutless bearing

I had the marine dealer replace a cutless bearing while the shaft was in. The propeller was removed...then a special tool pressed the old bearing out..then pressed the new bearing in. All while the shaft was intact. Complete task took about 20 minutes and no need to remove the prop shaft.

 

[Allan Frey]

>Is it obvious in some way?

Yes. Grasp the shaft at the prop hub and see if you can move the shaft up and down or side ways. There should be almost no play.

Allan

 

[dfhoch]

Cutlass Bearing Replacement

Great article! I'm wondering what you use for replacement criteria - how do you know when it's time for a new bearing? Are there symptoms like vibration or do you move the shaft a look for clearance?

David Hoch
S/V Abundance

 

[Max15631]

Pulling the shaft out with the rudder in the way is a hassle I faced with my ODay 34. Fortunately, I was able to disconnect it from the flange (after about 4 hours with a torch and hammer) and pull it out through the engine compartment. I also installed a dripless stuffing box at that time

 

[Highwind]

cutlass bearing replacement

A year ago I made a press after one I saw on the internet. Fortunately my 25 yr. old boat was used seasonally only in freshwater and only has a 1" shaft. With two 1/2 inch threaded rods and 1/2 inch plates that were reinforced I was able to push out the cutlass bearing using a split piece of heavy walled water pipe held in place with hose clamps. The plates distorted somewhat and the rods also bent, but I got it done. Pressing in the new bearing went a lot easier. I suppose it took an hour or so including the prop removal. Otherwise I would have had to remove the shaft and the rudder...

Nice documentation on Maine Sail's proceedure. The clever part I thought was using the set screw holes to peel out the old bearing.

 

[Maddog]

I had to replace both the cutlass bearing and my strut a few years ago. I had the strut designed so the tube that holds the bearing could be unbolted from the strut and be removed while on the shaft. I can then work on it in a vise back in the shop. I'll try it out this summer.

 

[rpfrehs]

Well done. My Hunter 34 is ready to have this done within a few weeks

I have heard several yards discuss this operation. Some said investing in a tool is best. Right now my 1984 Hunter 34 has the rudder dismantled and waitng for the crane to lift the boat, drop the rudder, pull the shaft and get to the cutlass bearing.

Seems like you can (or the yard) introduce lots of errors in the alignment of the shaft with this replacement.

 

[BobM]

but...

Dry ice and acetone will chill it down very well(minus about 175 degrees F) but if you drop it you may crack the rubber.

Better make sure the "rubber" is nitrile or the acetone might eat your bearing for breakfast.

Rubbing alcohol (isopropyl alcohol)/dry ice is a much safer combination, but is closer to -80 degrees C.

 

[Richard Bryer]

Re: Well done. My Hunter 34 is ready to have this done within a few weeks

I replaced the cutless bearing on my H34 several years ago. I lifted the motor with a couple of 2x4s across the companion way and my mainsheet system. The motor weighs just over 300# as I remember, so a 6:1 system means about 50# of lift. You dont need to go very high- just high enough to get the flange out thru the front. I did not need to unhook anything, there was enough play. (Undo the coupling first of course). You only have to take the nuts off the top of the mounts and if you make sure you hook the piece of chain on the lifting tabs so as it is balanced, you can sit the motor right back down with out distrurbing the alignment much if any. I used abot an 18 inch length and 2 of thos screw together links.

I cut the bearing with a hacksaw blade as MS did but in 2 places and tapped the strip up with a screw driver blade so I could get a hold of it then twisted it out, Sanded the inside with very fine paper and gently,then lubed it with a bit of white grease, cooled the bearing in the freezer over nite, carried it down in a bucket of ice- warmed the strut with a torch and VERY quickly rammed it in. Got it about 2/3 the way. finished by tapping with a block of wood and a hammer. Put the shaft back the way you got it out.

 

[ebaumes]

A better way to extract the old bearing.

Cutting the cutlass bearing risks damaging the strut. It is better to press the bearing out. Get a socket that is slightly smaller than the outer diameter of the bearing with 1/2 in drive.

Get a piece of pipe that is longer than the bearing. Use 1/2 threaded rod to pull the bearing out with the socket into the pipe.

I tried the cutting. It is tedious and hard to get an even cut. I switched to the above method and it was a breeze.

 

[Maine Sail]

Cutting the cutlass bearing risks damaging the strut. It is better to press the bearing out. Get a socket that is slightly smaller than the outer diameter of the bearing with 1/2 in drive.

Get a piece of pipe that is longer than the bearing. Use 1/2 threaded rod to pull the bearing out with the socket into the pipe.

I tried the cutting. It is tedious and hard to get an even cut. I switched to the above method and it was a breeze.

While this method may work some times and on some struts it may not work on others and may even destroy a strut.

My own boatyard owns a very, very expensive hydraulic press designed specifically for pressing out cutlass bearings. While it works well on about 80-85% of the jobs there are some that it just will not work on. The problem for a boat yard is you never know ahead of time which strut it will destroy. Another problem then becomes explaining to the customer that they now need a 3k strut job. My own boat yard has gone back to cutting out cutlass bearings or explaining that they can do it for less money with a press but there is a 15-20% risk that they may need to buy a new strut and pay to have it installed at a cost of up to 3k plus.. Most opt for the shaft removal/cut out procedure.

Products like the Strut-Pro, while a very good design, and one I'd personally like to own, are not 100% fool proof and you can damage your strut using them. This design though I think is better than the hydraulic units as you go much slower and could potentially spot a problem before you destroyed the strut. You need to keep in mind that the metal case around a cutlass bearing is only about 1/16th of an inch thick. If you flare it, and it gouges the strut on the way out, now you are in some serious trouble. If a socket was not the absolute perfect size it too could very easily flare the end of the bearing and cause more damage than a hack saw.

As I said the whole process including taking the photos took all of about 30 minutes and I did not even put one scratch in my strut from the hack saw..

Over the years, including my time in boat yards when younger, I have probably replaced about 20-25 cutlass bearings including 5 or 6 that were on my own personal boats. The one thing in common is that they all fit differently. Some are so loose that I would not even feel safe with them & some are so tight that I could not believe they actually went in at all. The cutlass bearings are fairly standardized but it seems struts can vary on the tolerances..

If a socket will push it out easily then go for it but if you hit some abnormal resistance when tightening the threaded rod stop and cut it out..!

 

[Warren Milberg]

Cooling Cutless Bearing...

When I replaced my cutless bearing, I bought it from Pyacht, which advises not to use dry ice to cool/shrink the bearing prior to insertion. This is the precaution they post on their site:

"Precaution: When Shrink fitting of the bearing is required, Chilling must be achieved by gradual cooling to not more than minus 20°F using a freezer or regular Ice. Do not use Dry Ice!"

http://www.pyacht.com/duramax-cutless-bearings.htm

 

[stickboy]

No colder than minus 20 huh?

When I replaced my cutless bearing, I bought it from Pyacht, which advises not to use dry ice to cool/shrink the bearing prior to insertion. This is the precaution they post on their site:

"Precaution: When Shrink fitting of the bearing is required, Chilling must be achieved by gradual cooling to not more than minus 20°F using a freezer or regular Ice. Do not use Dry Ice!"

http://www.pyacht.com/duramax-cutless-bearings.htm

I chilled my bearing in the freezer and it popped right in. 2 seconds later I couldn't budge it but it went right in.

As for the minus 20 degree limit, I better look into indoor storage next winter

 

[Rich Stidger]

OMG, three days before launch and I find my cutlass is bad

After all the discussion lately about these cutlass bearings, I rechecked mine thoroughly this past week. From side to side there was no play, but up and down it "clunked"!

I check this every year, but I suspect that I was pushing side to side and I didn't realize that it was as bad as it was. I could actually see a small gap- maybe 1/64 to 1/32 at the top of the bearing. See the first photo.

Now I panicked. I was afraid that I was looking at moving and re-blocking the boat higher so I could remove the rudder and then the shaft.

My boatyard said "no problem". We can change it in place.

They have a tool that is split and goes around the shaft and presses the bearing out. Of course I had to remove the prop, but fortunately that's not a big deal. Then they simply pressed the new bearing back in. Total of two hours of yard time.

This was MUCH less expensive than a boat move and re-block and the work saved in R&R the rudder and shaft was enormous.

I'm ready to launch with a nice snug bearing. Cool.

 

[alexco38]

Press it out?

Rich,

How did they get the old one out?

Did they use a tube or the new one to press the old one out?

Thanks

 

[Rich Stidger]

How did they get the old one out?

Did they use a tube or the new one to press the old one out?

Sorry, I should have been more clear. In the third pix the green tool part on the right is a split tube with the ID equal to the shaft size and the OD equal to the OD of the cutlass bearing. The two split halves of the tool fit around the shaft and a hose clamp is temporally used to hold the two halves together until the split sections enter into the strut pushing the bearing out. The hose clamp is then removed and the entire cutlass bearing is pushed out.

Actually the third pix is of the yard tech installing the new bearing. Here he has reversed the tool to use the flat side of the plate to push the bearing back up into the strut. The split tube sections face to the right toward the end of the shaft.

I really should have taken more pictures of the tool itself to show how it worked.

 

[Warren Milberg]

Yesterday, I happened to watch a guy replace a cutless bearing using nothing more than a large "C" clamp and two metal plates. While similar to the threaded rod method, this seemed easier and faster. Once the bearing was in place, the guy just turned the clamp and bingo he was done. Whole thing took less than 5 minutes....

 

[Frank_Ister]

Yes. You can replace a bearing with the shaft still on.

by using a "press" type tool. I'll have to try the C-clamp and plate method next time I replace. I just check for play as described to determine when I need to change the bearing

 

[MrCheapo(not)]

How bout you cheapskates just pony up the 100-200$

and have someone at the yard do it and save yourself the hassle!

There's plenty of other things to DIY

 

[John Nantz]

Removing Strut can be easy way

Recommended this before but I'll do it again. For me, removal of the strut is the fastest and easiest way to do the cutlass job.

Went 20 years on my first cutlass and it still wasn't that bad but I changed it anyway. Removed the prop and then the strut (four Phillips head machine screws) and took the strut home to the workbench that evening.

Saw cut the cutlass in two places basically the same as Mainsail opposite the set screws. Removed the cutlass but mine didn't come out very easy. I did win the battle.... eventually.

Honed out the strut with a wheel cylinder hone that had three spring-loaded fine strips. This provides and even distribution of load.

Pressed the new cutlass in using the workbench vice. Length of cutlass was 4 inches so the vice barely made the 8 inches.

Next day put the strut back on and went on with the bottom job.

NOTE: Some cutlass bearings will come out easy and some come out hard. Some go in easy and some go in hard. Just because Joe Blow's cutlass came out or went in easy is no reason someone else's will be easy. Why some people mention their's, or someone elses, went in easy is beyond me. All it takes is the absolute smallest of differences in dimensions to make all the difference in the world in how easy one goes in.