Saturday, March 19, 2016

Propeller Shaft Bearing

                                                   Propeller shaft Bearing

As expected the Propeller shaft bearing outside was deteriorated and needed replacement .
Since the bearing is tight in the bearing housing which is bolted against the hull it is not sensible to try to hammer the bearing out of the housing, In the first place when on add force to the bronze part of the bearing by hitting the metal it will expand and the actual bearing will get tighter in the housing. The other way is to remove the complete housing from the boat and then press the bearing with a hydraulic jack out of the housing, but then there is a chance that the bearing housing will not end up in line with the engine which will create another additional job.

To prevent both above options I decided to cut a groove in the bearing until the bearing housing. This was done with a Dremel tool and a small router suitable for metal, this is a slow process and one should make time to make the cut. I first tried it with a saw blade but this is not easy plus the fact is that it is very difficult to keep the saw blade straight in line with the bearing..

The following two pictures show the end result of the cut in the actual bearing.

When the cut is made it is easy to knock the bearing out of the housing with a hammer and a piece of wood, this since the tension is gone from the bearing which holds it in place in the housing.

 The bearing housing is cleaned and checked for damages. Then the new bearing needs to be inserted and as mentioned in the beginning it is not a good idea to try to hammer with force the new bearing into the housing, For example if it is not lined up properly it will result that the new bearing will get stuck in the housing which will result most likely in removing it and having to buy a new one.
In my opinion the best method is to slowly pull the new bearing into the bearing housing. This was done with a threaded rod and some plates covering the bearing at one side and the bearing housing at the other.

The bearing was lubricated with some oil and by turning the nut on the threaded rod the bearing slided relatively easy into the bearing housing without getting stuck. It is important with this method that the threaded rod is exactly in the middle to get an even force onto the bearing when it is pulled into the housing. As well as that the rubber of the bearing will not get damaged by the threaded rod.

As can be seen from the next picture the bearing housing is fitted with a new bearing which will last for several years. This was done for both propeller shafts.

 The removal and installation of the actual propeller shafts will be another chapter of this blog.
  Propeller shafts are planned to be installed this summer 2016 .

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