Hydraulic Steering and Autopilot Maintenance

[MikeNZ]

I know very little about maintaining my hydraulic steering and autopilot pump, and that worries me a bit as I do pretty much all my own maintenance. My questions are:

How long do hydraulic hoses last? Should I replace them periodically? Should I replace the hydraulic oil periodically?

I have very slight leaks at some of the joins (a drop over a few weeks). Should I tighten them a fraction or will this weaken the joints?

I have purchased a new Simrad AP28 with a new RPU160 pump. I have an existing older Roberston/Simrad AP also with an RPU160 (installed in 1992) and working fine (I'm keeping the old AP as a backup, so I can switch back quickly to it if my new one fails). At this stage I plan to keep the new RPU160 as a spare and leave the old pump in place, and connect the new AC42 computer to it. Do these RPU160 pumps wear out? Is there anything to look for to check it out?

My steering pump is a Capilano. My steering ram is a Hydrive. There are several flexible hoses in my system leading from under the centre cockpit to the steering gear in the stern.

Thanks, Mike

[forsailbyowner]

There shouldn't be any leaking at the joints. I had my ram rebuilt because there was a insignificant amount of seepage. Probably didn't need to as there wasn't much difference after the ram was honed polished and new seals installed. I replaced all my hydraulic lines when a transmission cooler line failed. All new lines (12) cost $400. Kept old lines for spares. Would probably just give the lines a little bit more torque. They should be just tight enough to seal without over doing it.

[GordMay]

Atbout 10 years.
The Society of Automotive Engineers (SAE) specifications state the shelf life of bulk rubber hose is 10 years from the date of manufacture and is considered unlimited for thermoplastic hose, if stored in subdued light and controlled temperatures with no fittings attached.

See Getting the Best Service Life From Gates Hydraulic Hose and Assemblies

➥ http://www.gatespowerpro.com/resourc...erviceLife.pdf

[donradcliffe]

While you have the new pump as a spare, you might get also get some brushes for the pump motor, as those seem to wear out before anything else on the RPU160 and they are pretty easy to replace.

[David M]

I have a hydraulic system on a research boat that powers two winches and an A-frame..as well as a separate hydraulic steering system and autopilot. Leaks are rare and so are hoses that burst. 10 years seems about right for replacing hoses. You will want an inline filter with your hydraulic system.

[MikeNZ]

Thanks for the quick feedback.

I will tweak the 2 joiners that have slight drips and look to replacing the hoses soon. Given the boat has had little use over the last few years (certainly nothing like 'commercial' use) I feel good about the trusty old RPU160 now. I'll order brushes as spares and hopefully my new RPU160 can sit in the spares locker and get sold when I sell the boat. So far my Simrad/Robertson gear has been totally reliable - really nice to get equipment that just goes and goes. BTW installing the new Simnet gear is a breeze! I also got a Simnet to NMEA 0183 connector so I can interface my old B&G Network Wind into the new Simrad AC42 computer so it can steer by apparent or true wind.

Mike

[sundown]

See if you can get "twist on" fittings for your hydraulic hose. Synflex makes a lined hose that you can get brass "Do It Yourself" ends. I used it for over 30 years and never had a burst steering line. An advantage of this system is that if you carry a couple of feet of extra hose and spare ends you can make repairs if the hose 'accidentally' gets perforated (though that is not very likely to happen).

[GordMay]

Eaton Aeroquip, Gates Hydraulic, and Parker Hannifin also make reusable hydraulic fitings.

Here’s some Aeroquip fittings from Grainger:
➥ Hydraulic Hose Fittings - Hoses - Pneumatics & Hydraulics : Grainger Industrial Supply