water in trim hydraulics, sticky ram

[tommr]

Is there a way to diagnose good or bad out drive trim rams and water infiltration?
I have a 1989 Wellcraft with the 120 mercruser and alpha drive. Yesterday we had a problem where the out-drive would not go to the lowest position when the switch was pressed. It goes to the full up position no problem but seems to stick at about 80% when extended which is just a bit above the bow up attitude. The pump tone changes to the sound as if the rams are fully extended, but they are not. I checked the reservoir and discovered the fluid was milky, but full.
I stood on the out-drive while my wife cycled the pump up and down and after several cycles it finally would go to the lowest position.
I assumed the water came from a recent rain storm where the reservoir cover was exposed to weather since the back seat was out.
After reading several posts regarding flushing the system I wondered if the water problem might be something else. For example a seal or a connection.
Earlier this year I had the whole thing out and apart to replace the bellows and seals and water pump and I had the rams off but not disconnected.
When I was re attaching the rams I discovered that one would only extend to about 80%. We managed to get them both attached and it worked OK, I figured the "good" ram was helping the "defective" ram to go the extra distance, and it seemed to be function OK and we have been using it all summer with out obvious issue.
I do not see any obvious fluid leaks around the rams or fittings.
So is there a way to find water leaks and what could cause one ram to stick.

 

[Scott Danforth]

water wouldnt come from a rain storm unless your boat filled up and the reservoir was under water, however most likely came from a failed seal in the rams.

if you have water in the system, you need to get it out ASAP. corrosion is the death of hydraulic components. if you do have sticking from corrosion, the rams need to be rebuilt

I suggest a complete fluid change as first step.

 

[tommr]

I am purging the system now. Is there a way to check the seals in the cylinders?
A while back I bought a tool box with tools including a set of snap on break line wrenches. I couldn't think of why I should keep them but I am glad I did. Some of those fittings are TIGHT.
If there were a failed seal in the ram would there be fluid leaking? Because I see no evidence of fluid leaking. It did rain hard and the top to the reservoir has a hole and it rained quite a bit the other day. I did not check to see how much water was in the boat but it drained for a long time.
Anyway, purging the pump and cylinders and hoses. One flaming hoop at a time.
Thanks

 

[Scott Danforth]

NEVER keep your boat on a trailer with the plug in it.

 

[tpenfield]

You can isolate the trim cylinders from the pump by connecting the hydraulic lines together.

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You will want to set the outdrive part way up and support it before you do this. then once the lines are connected, see if the outdrive lowers over the course of hours/days. If it lowers within an hour or even a few hours, it is a good sign that the trim cylinders are not holding their seal.

If the outdrive stays put, it is an indication that the pump is the issue rather than the trim cylinders.

the fact that you have water in the fluid points more to the trim cylinders though.

 

[tommr]

Thanks for the detailed answer.

If it lowers within an hour or even a few hours, it is a good sign that the trim cylinders are not holding their seal.

I do not see nor have I seen any fluid leaking around the cylinders but then again I have not investigated to see what hoses go where on the way from the pump to the manifold.

In your opinion, if the cylinder(s) is leaking, is this a seal as in what I can fix with a 25 dollar seal kit or a seal as in a 125 dollar thing with all the springs and parts that I would rather avoid until winter if possible.

The drive does settle, sometimes in a 24 hour period and other times not for a few days but I will preform the test to narrow the cause.

 

[JASinIL2006]

Don't forget to check the connections between the hydraulic lines and the cylinders. I had a water intrusion problem that turned out to me nothing more than a hydraulic line that had a loose connection.

 

[tommr]

Don't forget to check the connections between the hydraulic lines and the cylinders. I had a water intrusion problem that turned out to me nothing more than a hydraulic line that had a loose connection.

I am pulling everything apart to cleat out the gunk so I will make sure they are clean and tight. Thanks!

 

[wahlejim]

Alpha rams can be done with a seal kit, mercruiser part 25-87400A2

 

[tommr]

Well we are back in business and I have no earthy idea why.
I flushed all the milky fluid out by disconnecting the lines, at great difficulty, and ran the pump up and down.
It was still not working properly. It would go up but not all the way down. We cycled it numertous times with me standing on the out drive and Phyllis running the pump. But the pump made a strange sound like it had air in it when functioning down. Up was OK.
I tried it this afternoon and nothing doing.
This evening I went out and while I was waiting for Phyllis I checked the fittings and connection on the pump. Fitting appeared tight. Everything seemed fine. For good measure I gave the housing a sound thump with the back end of a heavy screwdriver.
She came out and ran the drive up all the way and down. The pump now sounded the same up and down and the drive went all the way down and up several times with no issue.

 

[wahlejim]

When you flushed the system, you introduced air bubbles, which is why the pump was sounding like there was air in it. Full up and down cycles will bleed the system. You may have also had a stuck valve inside the pump. The thump may have loosened it.

 

[Bondo]

Well we are back in business and I have no earthy idea why.

Glad to hear that Tom,....

I do have those rams I told ya 'bout, there's also a couple ole beat up short trim lines, 'n a pair of plugs to cap off the holes,....
Thought I had the lines, forgot 'bout the screw in plugs though,....

If ya wanta do more "Testin' ",... Feel free. 'n give me a call,....

 

[tommr]

Thanks Bill,
It was giving trouble again this evening and I wiggled wires to the pump and that seems to be it. That big round connector with the rubber boot. Must be a loose connection and maybe it got wet from the "great flood".
I hate to bug you, seems like the only time we talk anymore is when I am having trouble or I need to use a tool!