The complete seating system has proven to be quite durable, as all components of it on my boat are original and are in good working condition after 28-years of use, but this year (2018) the first component failure was experienced: the plastic seat bushing that intercedes between the aluminum 2-7/8-inch-diameter pedestal post and the cast socket on the seat base mounting plate failed on one of the two seats.
The plastic bushing--perhaps made of nylon or some similar material--lost the upper rim that bears onto the flat surface of the seat post. This area was abraded away, apparently aided by some rough surface on the top of the seat post that had gone unnoticed. The seat with the failed bushing was the port seat, not the starboard helm seat where I am normally seated, and the wear had probably been occurring for some time without my notice.
The bushing chose a bad time to fail: we were about halfway in our passage upwind in some rather rough head seas. With the failed bushing the seat became very loose and unstable, and could not be used for sitting.
Once we got into calm water, the seat was able to be returned to service, as long as the seat base was tightly clamped to the pedestal pole, but this eliminated any ability for the seat to swivel. Complete repair required replacement of the bushing.
Searching on-line for a replacement bushing, I found that Springfield Marine was making several types of pedestal seat bushings for their 2-7/8-inch pedestal posts. For guidance on which particular part to use for this c.1990 (and thus 28-year-old) Springfield seat base socket, I called Springfield Marine (Telephone: 417-725-2667) and was able to speak to a long-time employee who was very familiar with this product line and its history.
The appropriate replacement bushing is Springfield part number 2171001, and this bushing is available from West Marine at a very modest price of $12.99. Although West Marine is often cited as being an expensive source, their price was the best I could find on-line for this part. (Other sellers had it listed for about $22). I was also able to avoid shipping costs by having the bushing sent to a West Marine store near me.
About one week elapsed before the bushing was delivered to my local West Marine. Another few days elapsed before I got around to installing the new bushing.
The replacement part was not completely identical to the original, from what I could tell. The new bushing has a small molded post that projects upward, apparently intended to be seated in a locating hole on the inner lip of the seat base socket. On my c.1990 seat bases, the socket for the pedestal has no such locating hole. To resolve this problem, I called Springfield Marine for advice.
Again, their long-time employee (over 40-years with the company) explained how to remedy this problem; there were two options:
--cut off the little post on the bushing; or
--drill a hole in the casting socket to locate the bushing in a fixed orientation relative to the slide base. (This is the preferred solution.)
Both the original and replacement bushing were asymmetrical. The bushing has a varying thickness around its circumference, which is intended to impart a particular tilt angle to the seat base relative to the pedestal post. By orienting the bushing in one manner, the seat base will have a tilt-back of about 1.5-degrees; by orienting in the 180-degree opposing rotation, the seat base will have a tilt-forward of about 1.5-degrees.
Using the embossed part number of the seat slide base casting as a reference, if the thick portion of the bushing is oriented toward the casting number side, the seat tilts back; if the thin side of the bushing is oriented toward the casting numbers, the seat tilts forward.
The bushing also has a split, and the socket has two small bosses or ridges that the split can be oriented to sit on, oriented 180-degrees apart. The bushing also has a small relief notch to accommodate the second ridge when the main split is located on the first ridge.
My older socket lacked any drilled hole for the bushing post to locate on, and I decided to add one. To accomplish this the seat base was removed from the seat.
Using the new bushing as a guide, and with the new bushing inserted into the socket in the desired orientation, I established the position for the locating hole in the socket's lip. A small pilot hole was then carefully drilled, and the bushing placed in the socket to check the accuracy of the newly drilled hole location. The hole was then enlarged to about 5/32-inch to allow the bushing post to completely seat into the hole in the socket and the bushing to bottom out in the socket.
Before reinstalling the seat base with its new bushing onto the pedestal post, the top surface of the pedestal post was carefully refurbished with a metal file and progressive sanding with 200-grit and 400-grit emery cloth until it was restored to a flat and smooth surface. The pedestal top had received some damage, probably from those ridges in the seat base socket hitting the pedestal post top surface after the bushing failed. To further reduce abrasion between the aluminum post and the nylon bushing, I applied a small amount of teflon grease to just the top surface of the post, being careful to not get any on the post itself where the bushing will be compressed to fix the seat in place at a particular rotation.
The restored seat was placed back on the pedestal post, and it seems to work well.
- Fig. 1. Springfield Seat Base with new hole drilled for alignment pin
- SpringfieldSeatSocket1.jpg (44.77 KiB) Viewed 4175 times
- Fig. 2. Springfield Seat Base with new bushing installed and bushing alignment pin protruding through newly drilled alignment hole
- SpringfieldSeatSocket2.jpg (39.04 KiB) Viewed 4175 times