Trojan Boat Forum

I think one or both of my trim tab cylinders has a small leak. I am consistently losing a small amount of trim tab fluid when I run the boat. Insta Trim (Boat Leveler) sells replacement hydraulic cylinders. It looks like the cylinders are just held in place with pressed pins. Has anyone replaced trim tab cylinders? How hard is it to get out the old pins and put the new pins in? Thanks for letting me know.

The pins are plastic and only take a few seconds to drive out with a hammer and punch.

For not very much money, you can buy replacement seals and rebuild your cylinders. If you do that, you might want to consider putting some high pressure lithium grease on the seals and cylinders before re-installing the pistons. That got rid of some chattering that I had during retraction and was done on the advice of Insta-Trim.

The folks at Insta-Trim, especially Brian, are great to work with and took excellent care of me a few weeks ago when I had multiple problems with my system!

Had a similar fluid loss problem a few years back, turned out that the hydraulic hose had cracked where it connected to the cylinder and was not a cylinder problem. These cylinders are pretty robust. [embarrassing - going for a walk around a marina at night I saw a slick and commented to my wife about some arsehole dumping fuel; realized 2 days later it was probably my fault when I discovered the leak from the trim tab hose hose... !!!]

How I figured out I had a problem (and may help you figure out which side to look at) - I was on a run that was 1hr+. I trimmed both tabs down to where they needed to be for the run, but noticed that the boat took on a list and had to re-trim (pushing one of the tabs down) several times during the trip. The tabs were not holding their position. The one I needed to keep adjusting was the one that was leaking. Lost fluid, lost pressure, tab raised, boat listed, needed to push that tab back down again...

If you try that test, remember things are opposite... port tab down pushes starboard bow down... starboard tab down pushes port bow down. So of the boat starts to list to port after a while, the port tab/cylinder/hose is probably the problem.

Three years ago my starboard trim tab hose disintegrated where it connected to the cylinder. I replaced both hoses and things were good for the rest of the season. Two years ago the original trim tab motor failed and I replaced it. Everything is new except the cylinders. After a 6 hour run my trim tab fluid reservoir is at about half full. I checked for seepage at all of the connections and they all seem tight. I can't feel any leaks and there is no fluid in the bilge. The only other place I can think the leak would be is in the cylinders themselves.

My trim tab cylinders look like the original cylinders from 1971. I would not be surprised if one or both of them have developed a small leak when the system is under pressure. There are no obvious leaks when I lower the trim tabs when the boat is on the trailer. When the boat is running underway, however, I do need to "goose" the trim tab buttons every 15 minutes or so to maintain the proper running angle. The starboard trim tab cylinder may be leaking a little bit more than the port side, but I have to "goose" both buttons so it seems both are leaking somewhat. Given the age of the cylinders, I think I will replace both with new and be done with it. It doesn't seem like replacing them will be too difficult.

Agree will all the above. Could be an actuator leak or a bad hose. It's common for the hoses to crack just before the hose collar. If it's a bad hose, you can replace just a section but I prefer replacing the entire run. This is a good time to remove the hose trim/cover where the hose goes through the transom in case water is getting through. Remove the old caulking and reseal to ensure it's properly sealed. It's okay not to use the hose collar at the actuator and use a hose clamp instead. The collars are next to impossible to put on again.

It's also common for the hose nipple on the actuator to crack. If that's the case, replace the cylinder.

If oil is leaking at the actuator shaft, you can dismantle the cylinder and replace the seals however, check the surfaces inside the cylinder and the cylinder. If they are scratched/scored, they will continue to leak with new seals. You can contact Insta-Trim for a set of seals, they may send them out to you free of charge or a good marina parts store may carry them.

If water has gotten into the system and your oil is milky, replace with fresh oil. I like removing the old, adding new, cycle the system several times then dump the oil again and replace. Short of dismantling the system including washing out the pump, I find this is the next best way to help get rid of most of water contaminated oil.

I changed my boat leveler cylinders over the bennett cylinders. Bennett has a conversion kit for this, brackets included. What's nice is they there are no exposed hoses. The hose connection attaches where the cylinder attaches to the transom. Also I use the bennett trim tab zincs and change them without getting in the water by laying on the swim platform. Very happy with them.

I was constantly battling hose leaks where the hoses attached to the boat leveler cylinders.

Do a google search for "bennett V351CK"

I forgot to get a picture of the finished install, but here's the existing boat leveler tabs with the brackets installed so the bennett cylinders could attach to them. Notice the white marks on the hull above the trim tabs. The lower ones were where the old cylinders attached, the upper ones are where the bennett cylinders attach. Pretty much at the water line.

I think most would agree that the F26 was a timeless design. It's not easy to do.