Cutlass Bearing Removal/Installation Tool

 This is a modification of a tool I saw listed on the Internet. I do not know who designed the original or I would credit them for the idea.

I used two pieces of 3/8” thick x 4.5” square plate steel.
In one of the two pieces I bored a 1 3/8” hole in the center of the plate.

In the second piece I bored a 1 1/16” hole in the center of the plate.  I turned this plate so that it was diamond shaped and drew two lines from the outside edge of the centered hole to the edges of the plate.  Use a hacksaw (you will want a new blade to do this in 3/8” steel) and cut a 1 1/16” wide slot to the centered hole.  Lay one plate on top of the other and drill two ½” holes in the outside points of the diamond about 1” in from the points.

You will need a small piece of ¼”x 2.5” wide x 3.5” long steel for this next part.  Center a 1 1/16” hole in the ¼” plate.  Take the ¼” plate with the 1 1/16” hole and center the hole in the hole on the 3/8” plate that has the 1 3/8” hole. Once it is centered, clamp together and bore two-¼” holes in the upper two corners of the ¼” plate through the 3/8” plate.  What you are doing is making an adapter to decrease the hole size of your 3/8” plate from 1 3/8” to 1 1/16”.  You use this adapter to install the new cutlass bearing. 

The bearing removal insert is probably the most challenging to do.  If you do not have access to a lathe, drill press or ½” hand-held drill contact a machine shop to have this piece made.  I used a 1” black pipe (Lowe’s) 6” long.  My cutlass bearing is listed at 11/4” OD (outside diameter) but it is actually 1.255” or 5 thousandths over 11/4”.  I have a small wood lathe with a three-jawed chuck that I clamped the pipe into.  After cleaning up the sawdust around the lathe, I used a 4” grinder then a metal rasp, a metal file and emery cloth to turn the OD of the pipe to 1.245” or 5 thousandths under 11/4”.  You could also use a drill press with a long bolt and spacers through the pipe or a hand held drill in a bench vise.  Anyway to rotate the pipe as you use the grinder.  I had the lathe on a low speed and use calipers to check the diameter and make sure at least 41/2” of the 6” pipe is consistent.  After milling down to the correct diameter, I used a hacksaw and cut the pipe lengthwise then crosscut to a 41/2” length.  Don’t be too concerned about a perfectly straight lengthwise cut.  It is easier with a slightly wandering line to match the halves up to each other.  Use a hose clamp to keep the two pieces together.

 The last items you need are two lengths of ½” threaded rod each 12” long.  (Threaded rod is usually sold in 36” lengths).  Four ½” NC (national coarse) nuts finish the hardware.

 Removal/Installation of Cutlass Bearing

Before using the tool, the prop must come off the shaft.  (I actually spent about 2 hours removing the prop and about 20 minutes removing/installing the cutlass bearing so be prepared.  My problem was the cotter pin was corroded inside the prop shaft and I eventually ended up drilling it out with a newly purchased cobalt drill bit.) Once the cotter pin is out, remove the castle nut, turn the nut around and thread back on until flush with the end of the shaft. I used a 3/8” nut to protect the end of the shaft from the point of the 2-jawed puller and removed the prop with the puller. The reversed castle nut helps keep the threads from being damaged or the end of the shaft from expanding when the puller exerts force against the shaft end.

 After removing the prop, place the two halves of the bearing removal pipe over the shaft above the cutlass bearing and re-clamp the two halves together.  Wipe some marine grease over the entire pipe.

Remove the two stainless set screws that hold the cutlass bearing in the strut.

Line up the ½” holes in the two 41/2” plates and insert the threaded rods then thread the nuts on the rod ends. 

Spread the plates apart about 9-10” and slide the slotted plate over the prop shaft above the bearing removal pipe. Center the lower plate on the lower end of the shaft and check to make sure that the old cutlass bearing has clearance to get pushed through the 13/8” hole in the lower plate.

Gradually tighten the nuts on the threaded rods- a half turn or so on one side then move to the other side. Try to maintain as even a pressure as you can. When you reach the hose clamp on the removal pipe, take the clamp off.  The tool should be far enough in the bearing holder.  The bearing will probably make a loud “pop!” before moving-this is normal. 

Push the old bearing out and remove the pipe.

Wipe marine grease on the new cutlass bearing. Check the prop shaft for any burrs or sharp points and wipe grease on the shaft from the prop taper to the strut.  Gently slide the new bearing on the shaft up to the strut.

Take the small plate and bolt on to the lower 3/8” plate. Then spread the two 3/8” plates apart again to 9-10” and re-install on the shaft.

Again, gradually tighten the nuts on each side of the plates to push the new bearing into place.

Once it is flush, install the set screws with a drop of Loc-tite on each and put the prop back on.

Courtesy of Pete Hazel