Bennett Trim Tab Not Retracting

[Phil D Cooler]

My starboard trim tab will not come up all the way with the switch. Stops trying at 2 units. Port works fine. Starboard will come up when I turn the key off. Takes a longer than usual time, but it does come flush with the bottom. Hydraulic reservoir was just a little above minimum. Screws were a little loose on the top of the reservoir and it looks like it was leaking a little. Added hydraulic fluid and tightened screws. Didn't make any difference. Any ideas?

 

[Halfhitch]

Switch the lines to see if the problem stays with the starboard tab or if the port then starts acting up. If the port starts acting up after moving the line, then you know the problem is with fluid flow not the ram. First though, make sure you have plenty of fluid and cycle the tabs fully up and fully down through 3 or 4 cycles, making sure to continue holding the switch on in both directions for 5 or 10 seconds after they hit their travel limit to make sure all air is purged. It does not harm the system.

If the problem stays at the starboard tab after switching the lines then either the cylinder or the tab itself are binding. Figure it out from there.

 

[Phil D Cooler]

Thanks Halfhitch. On the road right now but will try it when I get home in a couple days.

 

[wspitler]

Could be electrical based on your description. I have had two rocker switches go bad on one side. If they both come up normally when they auto retract (key off) it points that way. The switches open a valve and run the pump either up or down. Key off puts power, through a timer, to the pump up direction and opens both valves. Try holding both switches (port and starboard) in the up position and see if starboard comes up. If so, you'll need to change out the rocker switches as the problem is with one of the switches activating the pump. See an electrical schematic for details. This troubleshooting is easier than messing with the hydraulics. You can actually remove the switches and short across if you understand switchology and wires to isolate it as an electrical problem versus hydraulic.

 

[Phil D Cooler]

I replaced the switches last year. Doesn't mean they're not bad, so I'll check. Thanks.

 

[seasick]

My starboard trim tab will not come up all the way with the switch. Stops trying at 2 units. Port works fine. Starboard will come up when I turn the key off. Takes a longer than usual time, but it does come flush with the bottom. Hydraulic reservoir was just a little above minimum. Screws were a little loose on the top of the reservoir and it looks like it was leaking a little. Added hydraulic fluid and tightened screws. Didn't make any difference. Any ideas?

What does it mean "Stops trying at 2 units"?

When it 'stops' is the pump motor still running? If so, your problem is not the switch.
I would try to pull the tab up manually while someone is pressing the switch. You might be able to use a boat hook to pull it.
In addition to a bad actuator, or a weak pump or check valve, the hinge on the tab itself might be binding.

By the way, it is relatively easy to remove the pump solenoids to check for debris and to clean them. They screw out of the pump housing and should be color coded, red for port tab, green for stbd.
Be careful not to lose the check valve ball bearing. It may fall out as you remove the solenoid.

Your tab may be working fine. It may be your indicators that are the issue especially since the tab retracts when the ignition is turned off ( auto retract)

 

[Phil D Cooler]

What does it mean "Stops trying at 2 units"?

When it 'stops' is the pump motor still running? If so, your problem is not the switch.
I would try to pull the tab up manually while someone is pressing the switch. You might be able to use a boat hook to pull it.
In addition to a bad actuator, or a weak pump or check valve, the hinge on the tab itself might be binding.

By the way, it is relatively easy to remove the pump solenoids to check for debris and to clean them. They screw out of the pump housing and should be color coded, red for port tab, green for stbd.
Be careful not to lose the check valve ball bearing. It may fall out as you remove the solenoid.

Your tab may be working fine. It may be your indicators that are the issue especially since the tab retracts when the ignition is turned off ( auto retract)

By 2 units I mean 2 indicator lights. They seem to be fine because when I physically check the tabs, the starboard one is definitely down a little (about an inch) and the port is up. When I turn off the ignition the tab does fully retract and the lights are out. When it stops at the 2 light indication, the motor is off. When I turn off the ignition it starts up again and brings the tab up and stowed.

 

[wspitler]

By 2 units I mean 2 indicator lights. They seem to be fine because when I physically check the tabs, the starboard one is definitely down a little (about an inch) and the port is up. When I turn off the ignition the tab does fully retract and the lights are out. When it stops at the 2 light indication, the motor is off. When I turn off the ignition it starts up again and brings the tab up and stowed.

That really points to an electrical problem, try running both switches up and hold the port switch in the up direction and it will run the motor and the starboard switch will open the valve. It may be the port tab is slightly faster than starboard and you are letting go of it when it gets full up, but the starboard switch will not run the motor alone.

 

[Phil D Cooler]

Tried all the suggestions but none worked. I had tried to squirt water between the tab and the bottom. Didn't work, but then got the idea to use a pressure washer. That did it. Whatever was in there got dislodged. Now the tabs working just fine. Thanks for all the suggestions.