Eos Rudder Bearing Replacement

(Update 8/2004: Apparently the Jefa bearing supplied by PYI failed after approximately one year on Eos. The reason for this failure is not clear, but it leaves open the question of using these as replacement bearings, Paul)

When we bought the boat one item on the survey was a suspect rudder bearing.  From the wheel, everything felt fine, but hand-turning the rudder when the boat was hauled, and hand-turning the rudderstock when the boat was in the water, revealed roughness.  A listing for another J/37 on the market noted that " the J/37 rudder bearing problem" had already been corrected on that boat, so we anticipated that one day we would need a new bearing.  However, the helm was light and sensitive, so we didn't give it further thought.

Fourteen months later we were headed to the start of an offshore race when one of the crew went below for coffee and said, "Hey, is there supposed to be water down here?"  The bilge was full, and with the heeling of the boat, water was pooling at the edge of the cabin sole.  Salty.  Heeled to port almost every through-hull on the boat was a possibility, but we started with a look in the lazarette.  The week before I had first noticed that the boat was built without a seacock on the waterline sink drain through-hull, which is in the lazarette just behind the companionway bulkhead.

The sink drain was intact, but looking aft I saw a steady flow of water from the flange at the base of the rudder shaft, about the volume you would see from a bathroom sink faucet.  That put a quick end to the race plans, and we immediately headed back to the dock.  We were able to stop the leak entirely by tightening the bolts that hold the flange down.  This made the steering very stiff -- it became fatiguing -- but we could still maneuver the boat fully.  The bilge pump then drained the water.

We hauled the boat the next Monday at KKMI in Point Richmond.  On dropping the rudder, it turned out that the packing on the lower rudder bearing was shot.  Rather than just replace the packing it seemed like a good opportunity to investigate the lower bearing.  The upper bearing was fine;  the lower bearing still turned fairly freely, but very roughly.  

It turns out that not only J/37s but probably every J/Boat ever built with Harken rudder bearings and sailed in salt water has a problem with the lower bearing.  That may explain why Harken no longer makes rudder bearings.  J/Boats builder TPI referred me to PYI, which carries a line of Jefa replacements for J/Boat bearings.  On the PYI home page I found a link stating "Rudder Bearing help for J-boats is here!" and on the page for J/Boat replacement bearings was a picture and listing for a bearing advertised as a drop-in replacement for J/34s, J/35s, J/37s and J/40s.  (PYI also has replacements for J/105s and J/120s.)

Concerned that the Jefa bearing would deteriorate just like the old Harken bearing, I spoke with a representative at PYI who told me the Jefa design involves a stainless inner ring, and that although the outer ring is aluminum the rings are separated by an intermediate delrin ring and delrin bearings.  The theory is that the dissimilar metals are never in contact and that the anodizing will protect the aluminum outer ring.  We shall see; there are still dissimilar metals in close proximity.  Edson makes both aluminum and some all-stainless bearings, but none were clearly a drop-in replacement.  Both the PYI and Edson reps were very helpful and responsive to both my questions and questions from the yard manager at KKMI in charge of the project.  In the end, I opted for the $962 Jefa bearing from PYI, and I had it 3 days later by UPS ground. 

Initially, it appeared that the inner ring on the old lower bearing was stainless steel and about 8 1/2" tall, extending well up the rudder shaft above the 2 7/8" tall outer bearing ring.  Based on that appearance, neither the yard manager nor I could understand why PYI thought the Jefa bearing they had sent me was a drop-in replacement.  The Jefa fit over the rudder shaft, but the inner sleeve, which extends only about 3/4" above the rest of the bearing, appeared to be much shorter than the original.  After being quoted $1,700 by PYI for a custom bearing with an 8 1/2" tall inner ring, I considered simply re-installing the old bearing with new packing.  With that in mind the yard crew pressure washed the old bearing, at which point it became clear that what extended above the old bearing was a separate stainless steel collar.  It appeared the Jefa bearing would indeed work, so we went ahead with replacement.

To ensure proper alignment of the new bearing and the old sleeve on reinstallation, the yard first made a 4-piece jig fitted to the old bearing and sleeve.  These consisted of 3/8" plywood sections cut to approximate shape, with wooden trim blades hot-glued in position flush against the old bearing and sleeve.  Each piece was numbered, and a correspondingly numbered outline was traced on the rudder shaft.  The old bearing was then cut away.  Both the inner and outer rings were aluminum, and badly pitted on both sides.  In some places the pitting (caked with crumbly white crud) extend from 1/2 to 3/4 of the way through the ring walls.  This confirmed the decision to replace the 15 year-old bearing.

After removing set screws in the sleeve, the yard drilled a hole on either side of the sleeve, inserted pins attached to a hydraulic puller, tensioned the puller, and heated the sleeve with a torch.  At about 3,000 pounds and who knows how many degrees, the sleeve came free from its epoxy setting.  The tension from the puller was enough to slightly deform the metal around the pin holes.

The Jefa bearing fit right in place.  The sleeve was cut down so that the total height of the new bearing and sleeve would match the original.  (This had the benefit of removing the areas deformed when the sleeve was pulled.)  Because the area that had been under the old packing was slightly pitted, the sleeve was inverted when it was re-installed to put a smooth surface against the new packing.  The bearing was then taped to keep epoxy out of the races, slow curing epoxy was applied, and the jig was fitted and clamped over the new bearing and the sleeve.

Inner and outer bearing rings, showing extensive pitting.  Some pits extended approximately 3/4 of the way through the rings.  Despite the extent of the corrosion, the bearing still turned fairly easily, if very roughly.  In the closeups, the horizontal lines top, middle, and bottom are the races where the ball bearings rode.

 
Sampling of ball bearings.  Some appeared to be pitted but felt smooth to the touch.  Most looked pretty good.

New bearing in place, with old stainless steel sleeve in place above it. Because of the configuration of the inside of the rudder shaft, the set screws supplied with the new bearing were too long and had to be replaced with screws that would lie flush with the bearing surface when installed.  Because the new bearing is slightly taller than the original, the sleeve was trimmed an equivalent amount.  Also, because the sleeve showed minor pitting where the packing material bore on it, on re-installation it was flipped end for end to provide a smoother surface for the new packing.  The stainless sleeve at the top of the rudder post inserts through the top rudder bearing.

New bearing and sleeve being epoxied in place, with alignment set by 4-part jig that was created before original bearing was cut away.

Reinstallation of the rudder required grinding away about a quarter inch of thickness from the underside of a 1" thick flange on the inside of the rudder tube so as to allow the new bearing to sit high enough inside the hull.

Back in the water, the steering is smooth as silk.  If this bearing is as good as Jefa and PYI claim, it ought to last at least another 15 years.