When replacing spun hubs, care should be taken to prevent
injury, as a great deal of pressure is necessary to perform this operation.
- A hydraulic press rated at ten (10) tons or better.
- The proper installation funnels, drivers and propeller
Several Lubricants will work, you may use any one of these
- P-80 Rubber Lube, supplied by McDurmon Distributing.
- McDurmon 6000 Hub Lube
- Propco P-100 Hub Lube
- Karo syrup
- Liquid dish soap and alchohol, mixed in 1:1 solution.
Whatever lubricant is used, it must be water soluble and
should not have an oil base.
Suggestions to make
- Soak new hubs in hot water, approximately 180 degrees F for a
few minuts. This does not harm the hub and will enable the hub to compress with less
- In cold weather, the prop itself should be soaked in warm
water. This prevents cracking the hub bore under pressure.
- Any hub with a cast flange on top - bevel the rubber at a 45
degree angle 3/16". This helps prevent the rubber from pinching between the flange
and hub bore during installation.
- Use our Rehubbing Alignment Fixture - This
fixture allows alignment to be maintained throughout the procedure.
Steps in Replacing Rubber Hubs
First, determine if the hub needs to be replaced.
If it is determined that the hub is bad, use the following
procedure to press the old hub out.
- Check for burnt or frayed rubber
- If the hub has a cast flange and the rubber is not visible,
you will notice bright or worn areas on the hub or the hub bore.
- If you are not sure a hub has spun - center punch the hub and
the hub bore. Have your customer test the prop on his boat. If the (2) two center punch
marks have moved, the hub is bad.
Now you are ready to press the new hub in. Be sure that the
ram is flat and square with the press table. If the ram is not square with the table the
hubs will go into the prop off center.
- Place the propeller on the correct funnel (measure hub bore to
determine which insertion funnel to use). Use the correct hub driver to push the old hub
out of the propeller and into the funnel. If the rubber cannot be pushed out of the
propeller, cut the rubber in several segments with a sharp wood chisel. This will make
- Inspect the propeller bore for cracks or damage. If the bore
is out of round, the propeller should be replaced - not the hub.
- Using the proper support under the propeller, select the
correct insertion funnel and hub driver you will need. Coat the insertion funnel and hub
with the lubricant and press into the propeller. You will know when the hub is installed
correctly when you can rotate the insertion funnel.
Note: Do not press the hub into the propeller with the prop
sitting on the diffuser ring or blade tips. Once the hub is installed, do not use the
propeller for twenty four hours. All hub replacement should be done at the customers risk.
Breakage of the propeller can occur and is usually caused by brittle metal or casting
Through the years hubs and propellers have been modified by
the manufacturers. Changes such as decreasing the outside diameter of the hub bore to
allow for better exhaust and manufacturing the hubs using a harder rubber to prevent
slippage. A hub is not a slip clutch. Its only purpose is to absorb shock to the drive
train when shifting.
List of Corresponding
Insertion Funnels and Hub Drivers
As styles change and new items are available, Rundquist will
tool up and provide additional insertion funnels and hub drivers.
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