Power trim won't move, pump makes noise, fluid full

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Jul 10, 2019
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2008 Volvo Penta 4.3 GL-J S/N 4012238806
2008 Volvo Penta SX-A 1.79 S/N 4202225761

Power trim quit while on the water. It seemed slow before but it wouldn't move at all while trailering but there is noise coming from the pump when the trim switch is moved up and down. We were able to lift it up manually to get on the trailer.

Checked the fluid with the outdrive down all the way. The fluid is full and looks just like the Volvo Power Steering and Trim Fluid in the bottle.

Where do I go from here?
 

alldodge

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We were able to lift it up manually to get on the trailer.

If you didn't remove the cylinders and still were able to lift the drive by hand, then there is a bad leak inside the cylinders, or a check valve is stuck open maybe
 

kenny nunez

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In addition to what A D said this is something else that can happen.
Sometimes when the brushes in the pump are worn or partially stuck the motor will make some weird sounds. If the motor sounds like it is running up to speed and no hydraulic pressure is being made then the end of the lower end of the armature shaft is not engaged and may have sheared off.
 

Scott Danforth

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Most hydraulic shops can rebuild or repair the oildyne pumps for a reasonable price
 
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Jul 10, 2019
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That makes sense. Either way the cylinders wouldn't hold pressure. Any way to isolate the problem between the pump and the cylinders?

What are the chances that both cylinders would develop internal leaks at the same time without leaking externally? Is it possible one could have been broken and the other was doing all the work?

When I first heard it trying to run I noticed the noise from the pump isn't the same and not as loud as when it worked but it's not moving the outdrive either. Does that help narrow things down?
 

alldodge

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What are the chances that both cylinders would develop internal leaks at the same time without leaking externally? Is it possible one could have been broken and the other was doing all the work?

Cylinders work in tandem and if one has a leak, that leak releases thru the other. There is nothing that keeps each cylinder separated from the other
 
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I didn't realize that. So are there any possibilities other than those two? Is there any way to verify which has failed without taking things apart?
 
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I have been away from home at work for several days and haven't been able to do anything with my boat. Someone told me that if the brushes were stuck I could tap it with a hammer while engaging the motor and that might free them.

Is it possible to generate enough force to do that without breaking the plastic cover?
 

kenny nunez

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Jun 20, 2017
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The Oildyne style motor is easy to take apart and to replace the brushes. If the brushes are stuck just clean them and use some dialectic silicone grease to keep them from binding. A 5/16” wrench will remove the 2 mounting screws.
 

Insomnium

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Apr 7, 2017
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54
Mine was noisy and not moving . Took it apart, cleaned it, re-soldered the connections to the brushes (they were coming apart at the connections) reassembled and runs great. I was amazed at how filthy it was inside
 
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I started taking it apart and it looks like I was wrong about the fluid. The fluid that came out was milky. It appears I have water in the system. I looked to see if there was any evidence of leakage and one of the cylinders had a drop of fluid under one of the fittings.

I'll post some pictures after I get them down to 2 mb.
 
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Jul 10, 2019
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This is what the pump looked like. I bought a new one.

There was peeling paint and corrosion under the cover. I need to clean that up and repaint it before I put it back together.

Getting the new wires through that hole looks like a challenge. They’re just long enough to get to where they plug in. Can I pull them through with the old wires?
 

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