Help - Trim Tab Stuck

[Matthewb]

Hi, does anyone have any ideas on the possible cause (and fix) for a jammed Trim Tab. Stbdside works fine, both directions, portside is stuck in the up position. I thought it might be a lack of oil so a quick check revealed it was very low. After a top up, the already working side is now very wizzy in both directions but the other is still not budging. I tried to "help it along" by pushing down at the same time as operating the switch. No joy. The pump is making a noise so it seems to be trying.

Does anyone have any ideas what the problem might be?

Thanks in advance,
Matt

 

[bdsweeting]

Have you got any air in the stubborn side ?

 

[Matthewb]

No idea - is there and easy way to check for that?

Matt

 

[Deleted User YDKXO]

First thing to check is if there is oil getting to the ram - just crack a joint on the hose and check if oil weeps out when the pump is running. If there's oil getting to the ram, then the ram must have failed or there is something stopping the tab or ram from moving. Is there any indication of oil in the water 'coz if there is, the ram seals have failed. Is the rod coming out of the ram free of barnacles 'coz that could stop the ram moving (that's why it's a good idea to lift the tabs up when you leave the boat)?. Have you checked around the tab for obstructions?

 

[Questor]

Had similar problem. Pump on mine, operates trim tabs and engine room hatch. One trim tab was iffy and engineroom hatch sometimes would / wouldn't lift, although pump always ran.

Problem was the solenoid valves which open the oil feed to the ram you want to activate. They cost about £15 each. Not alot, especially in boaty terms, so probably why they don't last long. Replaced all three last year, no problem since.

 

[stelican]

If they are Bennet tabbs It is probably the solenoid valve not operating these are mounted on top of the pump.
Easiest way to check is to swap the hydraulic lines over at the pump. operate the tabbs in the bow up postion before removing the lines to release the pressure you will get some spillage. the soleniod should have a single red wire to it

 

[SP2]

Hi - had the same problem with Bennett tabs this year - problem was a leak on the actuator (the arm) so pressure was lost. Tab stayed in the up position but other tab worked fine. Have you noticed oil leaking or on the surface?

Likely cause was O ring failure but as the cost of new actuator was modest replaced whole assembly.

Had excellent service from PH Marine at Wargrave on Thames who supplied replacements overnight.

 

[Matthewb]

Hi,
Thanks to everyone for their advice.

I think I will try checking the relays first, by just swapping them over to see if the broken tab then works. That sounds like a nice clean and easy job.

If that fails then I'll follow your advice Mike and check the lines to ensure that oil is getting all the way down the line to the ram.

I doubt it is a barnacle issue as I always leave them in the retracted position.

I'll take a look this weekend and let you know the outcome.

Thanks,
Matt

 

[robind]

are they bennet trim tabs?
If so mine do this as the hinge allows the non fixed bit to slide a little laterally and jams it on the fixed bit. have a close look through the water and try tapping it gently laterally one way or the other in case it should clear.
hope this helps
Rob

 

[brianrunyard]

Troubleshooting guide taken from Tabman
Forum run by Tom, who works for Bennett Marine, Florida.

Red= Port Valve
Green= Starboard Valve
Blue=Motor Forward (pump pressure)
Yellow= Motor Reverse (pump retract)
Black on HPU=Ground
Orange on Helm=Control Positive

Troubleshooting
1.If one side is not operating reverse hydraulic lines on the front of the Hydraulic Power Unit to determine if the malfunction is in HPU or actuator / hydraulic lines. If after reversing the lines symptom shifts to the other side the malfunction may exist in HPU. If the symptom remains on the same side, malfunction may exist with the actuator / hydraulic lines

2. Is the unit receiving a solid 12 volts? Low voltage will some times cause the solenoids to not open preventing the tabs from moving even though the pump motor is running.

3. Conduct the following test:
Remove the wires from the helm control and touch together as follows:
Operation=Reaction
Orange (+), blue, red= Port trim tab down
Orange (+), blue, green=Starboard trim tab down
Orange (+), blue, red, green= Both trim tabs down
Orange (+), yellow, red= Port trim tab up
Orange (+), yellow, green=Starboard trim tab up
Orange (+), yellow, red, green= Both trim tabs up
If the trim tabs function correctly for each wire grouping then the switch is at fault. Also note that any loose or missing screws on the back of the switch (whether a wire is connected there or not) can cause the pump to malfunction.
This test may also be done right at the pump by substituting a "hot lead" for orange. There is usually a connector to the wire harness within a foot or so of the pump. You want to check this connection for corrosion. You may wish to cut the connector off on the pump side and try the test on bare wires.

4. If you suspect corrosion on the wire connector near the pump, cut it out, test as above and reconnect using butt splices.

5. If you conclude the problem is in the pump, contact me. Bennett Trim Tab Systems carry a five year warranty. We also offer a trade in program for units out of warranty. Contact us for further details after you troubleshoot the system.

6. Check to see if there is a relay in line on the wiring harness near the hydraulic power unit. If there is it is an Interrupter Relay (IR1000). It prevents the system fuse from blowing if you try to actuate one trim tab up and the other down at the same time. After you test as outlined above, try removing the relay from the wiring harness and retest the unit. If it works the IR1000 will need to be replaced