Hydraulic steering failure

**hydroViper235** · 09-08-2024, 02:02 PM

Does anyone know of a hydraulic failure that caused a spill?
I've seen cables break.
Just curious if this can happen with hydraulic system

And why do some systems say 300hp but only 60mph?

**donmac** · 09-09-2024, 07:00 AM

300h.p./60 mph is likely an escape from liability for manufacturer, unlikely to have a boat completely upset under 60 mph!

hydraulic hose/fittings and heim joint failure are the most likely cause of a serious incident, where oil can be expelled at a rapid rate or ram completely disconnect from engine allowing engine/s to alter direction quickly would likely be catastrophic failures.

increased engine h.p./weight and steering geometry all affect pressure applied to the hydraulic fluid,ram,seals. requiring components with higher psi limits.

although it is unlikely to happen where both ends of a cylinder would have a line failure,with one end failing the remaining air free oil would hold the ram steady, if there's air in the system that theory goes out the door! the air can easily be compressed and expanded by engine torque!
I've never seen a complete failure in a cylinder but have seen the external retaining rods rods on a hynautic cylinder break which was likely caused by incorrect assembly torque of the nuts! inspect your system before each ride for leaks and fractures!

**Jim Speros** · 09-09-2024, 09:30 AM

the most common issue I've seen is the end glands slowly leak and system gets air in it and eventually looses enough fluid wheel spins freely. Once fluid gets aerated it tends to expand at rest and overflow.

**hydroViper235** · 09-09-2024, 09:55 AM

Thanks for the info!

**skialot2** · 09-09-2024, 11:46 AM

Something to think about. If you have ever seen a hydraulic failure, they almost always happen in kinda sorta slow motion. If a hydraulic hose develops a leak fluid leaks out, torque slowly turns the motor to the side with some resistance. But if a cable breaks, it's a quick snap to the side. No resistance at all.

**4Speed** · 09-09-2024, 07:13 PM

What about the bolt that holds the cylinder assemble to the motor?

**Jim Speros** · 09-09-2024, 09:19 PM

Its a special bolt. It threads into tiller arm and has a poly loc jam nut. I ave seen the threads in the tiller arm wobble out. Never seen the bolt break.

If it were to break the engine would hook violently right on a single engine application.

**skialot2** · 09-09-2024, 11:04 PM

If that bolt breaks the same thing is going to happen no matter what kind of steering system you are using.

**AlliStan** · 09-14-2024, 07:18 PM

I've had hydraulic steering issues, but never a sudden failure. A trick Michael Dixon showed me once is something that he did before every drag race with Boo or Casper. He rotated the steering wheel lock to lock a couple of times immediately before the race to help ensure any tiny air bubbles get worked out of the cylinder and lines. I do that now as a matter of practice before making a high speed pass, even if everything feels good. The Pro Hydraulic brand steering, that is now on my Allison, is far advanced beyond my old Sea Star, IMHO. It's rated at 700 hp and is much, much beefier. When I replaced the old Sea Star unit with it I left all my steering issues behind.

**AlliStan** · 09-14-2024, 07:32 PM

Originally Posted by Jim Speros

Its a special bolt. It threads into tiller arm and has a poly loc jam nut. I ave seen the threads in the tiller arm wobble out. Never seen the bolt break.

If it were to break the engine would hook violently right on a single engine application.

Amen. That bolt, or the "Jesus bolt", have to shear laterally to fail. Anyone who has any modicum of structural or mechanical engineering understands the huge forces required to shear a 3/8" grade 8 bolt that is tightened snugly. It's far more than any steering torque from a 2.5L O/B could ever generate, even if the lower unit hit a solid obstruction. I know people who replace the "Jesus bolt" every year, just because. That's ridiculous IMO. Those bolts don't "just break". The wrong nut backs off, or some other carelessness happens, but if the right bolt is in there with the right nut it won't just fail for no apparent reason.

**whipper** · 09-15-2024, 12:17 AM

There a clip from a while back were that bolt sheared on a hydrostream at speed. It hooked and barrel rolled. I replace mine every few years after I saw that. lol

**4Speed** · 09-15-2024, 07:06 AM

Does anyone know if the steering hydraulic fluid ever breaks down overtime and warrent replacement? I know in the power plants we use to perform oil analysis, change filters and hook up external filter carts to remove possible containments as a preventative maintenance task. I assume where the steering systems are so small and not a lot of velocity and generally leak free, the quality of the hydraulic issue probably not an issue(?)

**Jim Speros** · 09-15-2024, 08:39 AM

I don't know it breaks down but, some systems do get dirty. Latham power steering systems have a filter but, that system actually circulates. Manual systems don't have filters. Oil doesn't circulate it just goes back and forth. Nearly ever system I changed end gland seals on needed its fluid changed. I would always run a couple quarts thru when bleeding.

**KIRCHNER** · 09-17-2024, 06:07 PM

yes i had a failure. after river running all day,turning under bridges, around 45 55 mph, last turn of the day, just off plane[thank god] ths port bleeder blew out of ram,back of the boat was fluid everywhere ,i hit the bank at about 7-10 mph. instant loss of control. if that blew at speed, wow. angel on my shoulder that day!
,

**PaulR** · 09-17-2024, 07:24 PM

Originally Posted by AlliStan

Amen. That bolt, or the "Jesus bolt", have to shear laterally to fail. Anyone who has any modicum of structural or mechanical engineering understands the huge forces required to shear a 3/8" grade 8 bolt that is tightened snugly. It's far more than any steering torque from a 2.5L O/B could ever generate, even if the lower unit hit a solid obstruction. I know people who replace the "Jesus bolt" every year, just because. That's ridiculous IMO. Those bolts don't "just break". The wrong nut backs off, or some other carelessness happens, but if the right bolt is in there with the right nut it won't just fail for no apparent reason.

I had that bolt snap off in the mid 1990's on a dual Ride Guide system, the bolt was still fully threaded into the tiller arm with the nut still on it, that was the bolt Merc used back then. Luckly I was only running about 50-60mph, but the hard right turn still chucked me out of the boat. After that we all switched are boats to dual opposed cable steering, that way three bolts have to fail all at the same time to lose steering completely.