Hyd pump stopped working

[LeoKa]

It seems that my hydraulic system is back online. Sunday, I filled up with oil. First, it took 5 gallons and the tank level showed almost half full. I started the main engine and turned on the pump, but not any of the motors. The oil disappeared from the tank, so I added more. It took another 2-3 gallons and stayed at the same level as before.
The pressure was low on the scale, but there was pressure. So, I tested the bow thruster and it worked. I had a feel that it was smoother and faster in turning. I also moved the anchor chain back and forth, but being on a mooring ball, I could not test the anchor completely. Hopefully this weekend I can. See photos.

 

[LeoKa]

It seems that my hydraulic system is back online. Sunday, I filled up with oil.

View attachment 111386View attachment 111387

I thought I was done with this project, but I still have one question.
Since my first run with the new hyd system, I had to replace the oil pressure gauge, because it had a cracked glass. The new one is more sturdy and installed.
Over the weekend, I did a day trip and picked up fuel. At the fuel station, I had to use the bow thruster a lot, because of the tight space and current. It was working fine, but after a longer use, the thruster sounded differently and it seemed that did not do much turning. It was like the pressure was gone. I kept trying to turn it, but not much happened. I had to turn off the hyd pump and start the maneuver all over again. At the second round, I was able to get closer to the dock, but I still needed the thruster, so I turned it on. It worked and I was able to dock.
After fueling, I headed home and did not use the hydraulics. Once at home, I have tested the bow thruster and the windlass and they both worked. I let the anchor down about 5-6 feet and pulled back up. All was fine.
However, when I went to the ER, while the hyd pump was engaged, I could not see any pressure on the gauge. Again, all hyd was working, when I used it. I cannot see the gauge while I am in the PH, so I don’t know what is the pressure during use.
My question is; is this normal? Should not I have some pressure on the gauge all the time, as long the clutch/pump is engaged, even without using any of the equipment? I remember, the previous setup always showed some pressure. The only difference now is the filter assembly on the return high pressure hose at the tank.
Any suggestions?

 

[Irish Rambler]

Did you fit an oil cooler into the hydraulics, if not it will lose power as the oil gets hot.

 

[stubones99]

I thought I was done with this project, but I still have one question.
Since my first run with the new hyd system, I had to replace the oil pressure gauge, because it had a cracked glass. The new one is more sturdy and installed.
Over the weekend, I did a day trip and picked up fuel. At the fuel station, I had to use the bow thruster a lot, because of the tight space and current. It was working fine, but after a longer use, the thruster sounded differently and it seemed that did not do much turning. It was like the pressure was gone. I kept trying to turn it, but not much happened. I had to turn off the hyd pump and start the maneuver all over again. At the second round, I was able to get closer to the dock, but I still needed the thruster, so I turned it on. It worked and I was able to dock.
After fueling, I headed home and did not use the hydraulics. Once at home, I have tested the bow thruster and the windlass and they both worked. I let the anchor down about 5-6 feet and pulled back up. All was fine.
However, when I went to the ER, while the hyd pump was engaged, I could not see any pressure on the gauge. Again, all hyd was working, when I used it. I cannot see the gauge while I am in the PH, so I don’t know what is the pressure during use.
My question is; is this normal? Should not I have some pressure on the gauge all the time, as long the clutch/pump is engaged, even without using any of the equipment? I remember, the previous setup always showed some pressure. The only difference now is the filter assembly on the return high pressure hose at the tank.
Any suggestions?

If you have an open loop hydraulic system, you'll have hydraulic oil flow through the shuttle valves and pipes, through the pump and back to the reservoir. You won't measure much pressure unless there is a load, since any pressure measured would be causing more resistance at the pump, taking / wasting horsepower. When you move a shuttle valve to push the oil flow through the thruster, anchor winch, etc., you'll see the pressure spike, the higher it goes, the more force it is using at the thruster or anchor winch.

 

[LeoKa]

Did you fit an oil cooler into the hydraulics, if not it will lose power as the oil gets hot.

No, there is no cooler in the system. So, that explains the situation.
Thanks.

 

[LeoKa]

If you have an open loop hydraulic system, you'll have hydraulic oil flow through the shuttle valves and pipes, through the pump and back to the reservoir. You won't measure much pressure unless there is a load, since any pressure measured would be causing more resistance at the pump, taking / wasting horsepower. When you move a shuttle valve to push the oil flow through the thruster, anchor winch, etc., you'll see the pressure spike, the higher it goes, the more force it is using at the thruster or anchor winch.

This makes sense.
Thanks for the explanation.

 

[C lectric]

Install a cooler. It may not always be needed but as you found if conditions mandate extended use you may lose some function if the oil gets to hot.

If it is really hot for long enough seals can be damaged. I doubt they would leak immediately but longer term any heat damage to a seal will allow leaks and maybe inproper function at some point.

The cooler would be installed in the return line, near the filter, coming back from the loads. That way the cooler does not have to withstand full operating pressure.

I would also install a HYDRAULIC rated shut off valve at the guage so it can be isolated. THey can fail allowing leaks and if used only when checking the pressure they will last far longer. ALso if it does fail then the valve can be shut.

I agree about the lack of or more likely very low pressure when the system is not actively operating something.

The pressure may be so low just circulating oil that the pressure will not be shown on the guage.

 

[LeoKa]

Install a cooler. It may not always be needed but as you found if conditions mandate extended use you may lose some function if the oil gets to hot.

The pressure may be so low just circulating oil that the pressure will not be shown on the guage.

I don’t know much about oil coolers. Would it be a specific cooler for hydraulic oil/system?
The problem is, I had difficult time to figure out where to position the tank/filter/shut off valves combination, so I am not sure, if an oil cooler can be fitted in? I can certainly try.
Now that I know, what could happen; I will be more careful with overusing the thruster. Do you think, pulling/dropping the anchor would also heat up the oil significantly, just like the thruster did?

 

[Portage_Bay]

How big is your hydraulic reservoir? If it's large enough and there is good ventilation around it a cooler may not be needed. Check the temperature next time you use the system for an extended time. You don't need a cooler designed specifically for hydraulic oil. It won't see much pressure if on the return side near the tank. But it does have to have enough capacity to not restrict the flow. A cooler will be another potential failure point.

 

[LeoKa]

How big is your hydraulic reservoir? If it's large enough and there is good ventilation around it a cooler may not be needed. Check the temperature next time you use the system for an extended time. You don't need a cooler designed specifically for hydraulic oil. It won't see much pressure if on the return side near the tank. But it does have to have enough capacity to not restrict the flow. A cooler will be another potential failure point.

The reservoir tank is 10 gallons. I think the rest of the system is no more than 3-4 gallons (pump, hoses, valves).
The tank has a side gauge, which shows temp, as well. The oil level normally sits around mid gauge. This time, the level went up to 3/4 level, due to the temp rise, I suppose.

 

[Portage_Bay]

You said you worked your thruster hard. I'm thinking that's minutes not hours. You also said you made a second approach and it worked better. I'm thinking there wasn't enough time between approaches for the hyd oil to cool off.
In my opinion there's something else going on besides thermal expansion.

10 gal tank + 4 gal system = 14 gal.
Tank level going from 1/2 to 3/4 = 2.5 gal
2.5 gal expansion is 17.9%

That's signifies a huge temp increase in your system.

I'd contact a good hyd shop to see what you need. Before doing that I'd get a buddy to help. Run the system hard, record initial level, temps and pressures. When the system seems to get weak note those values. And the time it took for that to happen. The hyd shop will be better able to help you with that data.

I used to run a much bigger system than yours. A winch, sometimes two winches and a crane working for hours. Then pick up a 300 lb hook and hundreds of feet of 5/8 chain and cable. We never lost power due to hyd oil temperature and didn't use coolers. We did have about 45 gal in the reservoir. But as I said, a much larger system working a lot harder.

I'm not a hyd system engineer so I could be wrong about not needing a cooler. Hence my recommendation to contact a good hyd shop. I've used both Max Performance Hydraulics and Puget Sound Hydraulics near Fisherman's terminal.

 

[Xsbank]

What temperature did you witness on the tank gauge? Mine sits at 120* and although it radiates a lot of heat into the engine room, that's about right.

I noticed that there is no valve on the return filter, that will cost you a lot of fluid when you do filter changes. Your oil will soon turn black but that's pretty common and not sufficient reason to change it. But the filters I change when they get black. That's a year or more.

Did you clean out all the supply hoses when you overhauled? You may have plugged the filter a bit after your startup? Presumably with no services being used and your pump running, you will see a bit of pressure if the filter clogs. The lines and the motors may be harbouring some spooge.

How do you run it? I have an hydraulics on switch, I select crane or windlass with a manual selector. When I move the lever at the crane, it works (well it did when I last used it...) and I select up or down there.

Have you adjusted the pressure selectors? They might be incorrect for the new pump?

I hope this works out for you, hydraulics are excellent!

 

[LeoKa]

You said you worked your thruster hard. I'm thinking that's minutes not hours. You also said you made a second approach and it worked better. I'm thinking there wasn't enough time between approaches for the hyd oil to cool off.
In my opinion there's something else going on besides thermal expansion.

You have a point. I will do the test you have recommended.
Just a note; all equipment I have replaced comes from the same manufacturer as the previous one. The hoses were professionally made by the local fitting shop. Except the solenoid valves, everything is new. I had only one new item, the filter. It also has a gauge and shows normal conditions. Hyd grad ball shut off valves were added at the tank and at the solenoid valve in the bow.
It will be interesting to know, what cases the significant temp change of the oil? Or, what is the reasonable limit of my system, before things heat up too much?

 

[LeoKa]

What temperature did you witness on the tank gauge? Mine sits at 120* and although it radiates a lot of heat into the engine room, that's about right.

Have you adjusted the pressure selectors? They might be incorrect for the new pump?

I hope this works out for you, hydraulics are excellent!

Everything is new to the solenoid valve and back. Hoses, pump, clutch, safety valve, ball valves. Oil was replaced twice. It looks very clear.
There is a ball valve before the filter, it is just hard to see on the photo.
The hydraulics is turned on in the PH with a switch, which engages the clutch in the ER to the pump.
The windlass has a separate up/down rocker switch.
The bow thruster also has a separate rocker switch for function.

I was in a difficult docking situation and I used the thruster a lot. It came back fine, after few minutes.

I will check the temp next time.

What pressure selector are you referring to?

 

[Xsbank]

I see I missed a whole page of posts, sorry if my last post is peculiar.

I have pressure adjusters (that I have no idea how to adjust them or how to tell how they're set) that, I believe, are adjusted by installing coloured rings (voodoo). That was a stab in the dark, hoping that was something you might have found out.

I suspect that your system might be too big for your pump; you might need a selector valve, to shut off the unused system. My system can only supply fluid to the crane or the windlass, not both, so I have a selector that just slides back and forth.

 

[LeoKa]

I see I missed a whole page of posts, sorry if my last post is peculiar.

I have pressure adjusters (that I have no idea how to adjust them or how to tell how they're set) that, I believe, are adjusted by installing coloured rings (voodoo). That was a stab in the dark, hoping that was something you might have found out.

I suspect that your system might be too big for your pump; you might need a selector valve, to shut off the unused system. My system can only supply fluid to the crane or the windlass, not both, so I have a selector that just slides back and forth.

I have the exact same pump (new) as I had before. The reason for the replacement was a pressure breakdown. First I thought it was the pump and the clutch, but it turned to be a hose in the bilge. It was leaking. I replaced everything, including the hoses.

I do not have them both online (windlass and thruster) I never had to. I use the thruster for docking only. Windlass is only used at anchoring. Again, everything moves and works, I just had this one moment, when the thruster did not turn enough. Possibly, due to overheated oil.

 

[C lectric]

I don’t know much about oil coolers. Would it be a specific cooler for hydraulic oil/system?
The problem is, I had difficult time to figure out where to position the tank/filter/shut off valves combination, so I am not sure, if an oil cooler can be fitted in? I can certainly try.
Now that I know, what could happen; I will be more careful with overusing the thruster. Do you think, pulling/dropping the anchor would also heat up the oil significantly, just like the thruster did?

There are coolers made for hydraulic systems. THe place you got your hoses from should be able to help size and supply it . I am going to guess a bit but it may not need to be very large so could be mounted on the tank top or side with some additional plumbing, darn.

It will need some water supply to carry off the heat which could be from the raw water supply. Probably only a small supply needed. Engine coolant will be too hot.

The suggestion to do a serious test with the help of a friend to cycle the windlass and thruster to heat the oil. It took a while before I saw the temperature guage mounted on the filter.

Hydraulic systems ALL develop heat especially when they are working but even just idling they will heat the oil. On our machines at work the heating system was the pump itself for 10 to 15 minutes at something like 1500PSI to get to the minimum working temp.

Just as important was the cooling system when the machine was working or it would have boiled and burned the oil damaging seals. Yes, it happened. We had machines ranging from 20 gallons to about 700 gallons.

So if your system is running all the time that the engine is running then even if you do not use the system it is warming up and eventually MAY overheat. As mentioned it may not as direct heat radiation to the engine room may be enough but when working maybe not. The test should give you an idea.

While you are monitoring the system keep track of the idling pressure and the working pressure with all of the devices as you exercise each and keep notes.

For mounting the cooler I see the tank has a lip that overhangs the tank sides. Your hydr. shop should be able to help here again with the use of some UNISTRUT which with the various clamps and strut sizes should be able to make a solid mounting base for the cooler on the tank top. There may be other options that I cannot see.

DO the test, monitor the temperature and pressures as you exercise the system. ALso idle the engine for approx. the length of time the engine was idled the day you went to refuel. Keep track of the time as the temp rises.

Enough for now, see what happens.

Happy hunting.

 

[plittle2005]

This is probably just a stone-axe simple gear pump/gear motor 2-spool directional control valve circuit. Any fishing boat hydraulics guy could restore it as needed. It is a very common circuit design



Find a fishboat repair hydraulics guy, he could fix it in short order. But it must be done properly. If you have never serviced this corroded mess, then just start from scratch with disassembly, cleanup, new components as necessary (FishBoats-R-Us-Supply, or ForceAmerica) new filters, fluid,...just get a competent fishboat or industrial/mobile equipment mechanic,tell him fix it, go have coffee!


They really are simple systems, but ya gotta know hydraulics and then take care of the system.

 

[LeoKa]

They really are simple systems, but ya gotta know hydraulics and then take care of the system.

Fix what?
I have everything new installed.
FORCE pump/clutch. Hoses, valves, tank, filter. All new.

 

[plittle2005]

Fix what?
I have everything new installed.
FORCE pump/clutch. Hoses, valves, tank, filter. All new.

You need to understand how the hyd. system works and how to service it. Get a competent hyd. guy to show you exactly what you need to know,help you put it together. It's a simple system but you must know certain things about industrial fluid power to keep it working successfully.Just get the tutoring.

 

[LeoKa]

You need to understand how the hyd. system works and how to service it. Get a competent hyd. guy to show you exactly what you need to know,help you put it together. It's a simple system but you must know certain things about industrial fluid power to keep it working successfully.Just get the tutoring.

I did not design the system. The original builder of the boat did it 20 years ago. I just replaced everything with the same items, from the same manufacturer, as the original was, due to a broken hose. Did you read the whole thread here?
There are lot of competent guys here on the forum, who understand hyd systems.

 

[Xsbank]

This is my hyd. Pressure regulator. Sorry for the tilted photo.
The upper thing is the on/off solenoid. When it opens the pressure rises and that small line that turns 90* left tells the pump it needs pressure and it then supplies more fluid and pressure to run whatever my system requires. Above that hose is the pressure reg., it looks like a knurled knob. Below it is the crane/windlass selector. It moves in and out by about 3/4."
I never use that cooling fan because it howls so loud I can't stand it. In fact it is nearly history, I am redoing the engine room cooling.