Hydraulic user offers maintenance tips
|From Ocean Navigator #118 |
In 20 years of use, I have gained some experience with this device and disagree with the author somewhat. I have only had two failures. The first to fail was the lip seal around the shaft of the helm pump. This is a very slow failure item that begins to weep after some years of use. Personally, I think that sunlight and time are the culprits. In any case, the seal is easy to change by draining the pump, drilling two small holes in the seal rim to take two sheet metal screws that are then pried out with two pry bars. Then tap in the new seal and replace the hydraulic fluid. This failure is very slow and can be ignored for months. There are no other parts in the helm pump that are not made of metal. There are two bearings, but because of their low-stress conditions they should have a long life.
The major failure was the seals in the hydraulic ram's piston. This happened to me about 15 years after the unit was built. Fortunately, I was on a river when the boat suddenly would not turn left. We turned right and anchored. I got out the spares and learned a big lesson: these seals deteriorate at the same rate whether they are in use or on the shelf! The shaft seals were not leaking, so I left them alone. The two piston seals were shot and came off in pieces. These seals consist of a ring with a square cross-section but with a bit of a lip on the outer diameter facing the pressure side. When I tried to stretch the spare seal over the piston, it broke into three pieces. I put the pieces in the groove, cut the second seal into two halves with a sharp knife and placed them in the groove. After putting everything back together I proceeded to port and had Wagner air-ship me a new set of seals the next day.
The lesson is obvious. Spare ram seals deteriorate at the same rate as the seals in use. For me, both went bad in 15 years. I think one should change seals every 10 years and not bother with spares.
I don't know how long the hoses will last. I have copper from helm to about two feet from the ram, where there is a section of rubber hose. I believe the same situation is in effect with the rubber hoses, but I don't know the time factor - at least not yet.
A similar situation is in effect with engine hoses and v-belts. I changed them five years ago and they still seem to be quite robust. Would 10 years also be a good replacement period? Here heat is a factor, unlike the steering system, so perhaps it would be a shorter period, or perhaps these items are built to resist the heat.
Although the article I am responding to says that steering system manufacturers specify automatic transmission fluid be used only in an emergency, the manual that came with my Wagner equipment told me to use ATF without the "emergency use only" specification, which I did for years. Although I eventually did change to normal hydraulic oil on the advice of people experienced in the field, this may have caused a premature failure of the piston seals. I still had to pay Wagner for the new seals and FedEx charges.
Norm Johnson was in Maine this past summer aboard his homebuilt, 63-foot motorsailer Bandersnatch, designed by Bill Luders.