Autoprop H6 bearing removal
The disassembly of the Autoprop H6 propeller reaches a climax in this post when the last remaining parts are removed from the propeller. In the last post we took off the blades and the bearing races, in this post we remove the bearing tracks from the blade and the boss (no mean feat) and take all of the seals and o-rings off ready for the propeller to be sanded, cleaned and rebuilt.
Removing the Bearing Tracks on the Blade
By far the hardest part in taking an Autoprop sailboat propeller apart is getting the blade caps off. Once these are removed the condition and quantity of the grease pin the blade bearings will give you some indication as to how difficult the removal of the blade tracks can be. The H6 propeller is a great rebuild candidate as all of the wearing parts are replaceable, with the service life typically dictated by the users vigilance on replacing anodes. If there is plenty of grease in the blade bearing, chances are you will be cleaning the grease and teasing out the tracks, if there is any sign of rust, you will be in for a ride!
Easy Bearing Track Removal
For well greased bearing s the removal of the track is simply a little bit of elbow grease. The tracks sit in a channel that is a clearance fit - i.e. very tight. Often it is the grease and debris in the channel that holds the tracks in place. The blade bearing is the most difficult as unlike the hub tracks, there is no place to lever out the track using a screwdriver. Instead it must be separated from its channel in a parallel manner often by using a soft mallet on the back of the blade. Any rust causes the track to bind to the blade and more mechanical methods must be resorted to.
For this propeller an automotive degreaser, a toothbrush, 20 minutes and a soft mallet were used. Once the grease was broken down the track did slip in its channel and it was a case of working it back and forth, scrubbing, drying and tap, tap, tap. Do be careful on the older models as if the blade is fragile the bronze will chip away from the bearing seats and can render the blade useless. Removal of the track reveals the channel which once inspected for damage can be cleaned and made ready for the new bearing.
Hard Bearing Track Removal
If the bearings are rusty, a whole new ball game takes placed it is ingenuity to get them out with a little bit of luck. Typically we use a ceramic cutting wheel on a Dremel to cut a groove wide enough to get a screwdriver in. In some cases the chasing of the track using the screwdriver in this slot with a soft mallet can free the track. Most of the time however I am cutting the track deep enough to remove a small section that will allow a screwdriver underneath to leverage it out. We also drill into the track with a high strength drill bit enough to wind a bolt into the hole so a pair of pliers can be used to pull it up out of the channel and freedom.
Whichever method you use, the single most important thing to remember is not to damage the bronze channel on the hub. Don't drill too deep or cut / slip too wide as the damage can be costly.
Removing the Bearing Tracks on the Hub
Compared to removal of the blade bearing tracks, the hub is a piece of cake. The channel retains the track is asymmetric allowing a screwdriver to be located on the inner edge of the hub close to the blade post. The gap gives enough space to lever the track of with relative ease, rusty or greased. Again inspect the channel and clean ready for the new bearing.
Removing the Lipp Seals
The integrity of the grease trap on the blade is maintained by a large lipp seal embedded into the blade. The seal has to be pulled out with a pair of bull-nosed pliers and this operation often tears the sharp sealing edge of the seal. Once a small part is clear of the channel it sits in the seal can be pulled off in one go or a screwdriver shaft can be slid into the gap and the seal gently eased away from the blade. Once removed it is again inspected and cleaned. The location of the lipp seal channel is such that it is prone to chipping when the propeller bronze gets old due to salt water exposure and cathodic actions. If there are any sections missing this could shorten the life of the propeller significantly and allow sea water into the blade bearing with obvious consequences.
Removing the O-rings
The last part in the teardown of the propeller is the o-ring seals on the blade caps. If the caps have not been removed previously and the propeller has been painted, the seals could be painted on and look just like... paint. Again removal of the seals is a destructive process, especially for old seals. You may have to cut them out with a utility knife. Simply break the seal and remove the entire seal, cleaning the area paying special attention not to damage the threads on the blade cap.
This concludes the tear down of the Autoprop H6 propeller. You should by now have a fully disassembled Autoprop, ready for cleaning, inspection and the installation of a new bearing kit. In the next video we cover the preliminaries needed prior to the rebuild. To see the full video of removing the bearings from the Autoprop H6 propeller, click on the video below.