Hydraulic Lift Platform on SR410DA

M

Max

Member
Jun 26, 2010
55
Iowa
Boat Info
2000 Sea Ray 410 Sundancer
Engines
350 Cat
I have a 2000 Sea Ray 410 with a Hydraulic swim platform on which I park my dinghy. The lift is rated at 800# and the dinghy weighs in at 550# with motor.

The lift had been working fine up until I launched the boat this year after winter storage. While the lift does raise completely without the dinghy, it will not with the dinghy. The port side goes all the way up but the starboard side stops about 1.2 inch short. I believe there is some sort of latching system when it is all the way up, so I am concerned that it will drop while under way.

I have checked the hydraulic fluid and all is good there. My unprofessional opinion would be that the starboard side cylinder is going bad - perhaps some internal seals allowing the fluid to bypass. There are no external fluid leaks, nor does the fluid reservoir level drop.

So I am wondering if anyone has had a similar situation and if so, how was it resolved. The other issue is that none of my manuals deal with the lift so short of pulling the boat, I am not sure what make/model the lift is.

thanks
 
Stupid question, maybe but are your batteries fully charged? My Sea Lift chokes, if not. Although since one side goes all the way up, probably not your issue. Have you tried reversing the dinghy, just to test?
 
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ziekman@cox.net said:
Stupid question, maybe but are your batteries fully charged? My Sea Lift chokes, if not. Although since one side goes all the way up, probably not your issue. Have you tried reversing the dinghy, just to test?
Click to expand...

Thanks, yes the batteries are at full charge. There is additional weight on the starboard side due to the outboard motor on the dinghy. I have davits made for the (v bottom) dinghy so reversing it is not an option. Given that the platform will go all the way up without the dinghy, reversing it would probably work, temporarily. But since it worked fine this way for that past two seasons, I would rather address the problem.
 
Try a search on here..... This has been discussed before, I just can't point you to when it was. It seems like it was a fairly simple fix. Do you know who manufactured your lift? A quick call to them would likely yield the solution.
 
...and you're sure you don't have any leaks from the cylinder itself or with any of the lines and fittings running to/from the pump either inside or outside of the boat? My lift is a Nautical Structures but TNT was put on a lot of boats in this timeframe. I don't think they started putting on GHS until '02 or later but someone will have to verify that. Put a call into SR and I'm sure they can tell you what it is if they put it on. When my lift was sagging to one side, I had a leaking seal. I could refill the fluid and raise it w/ no load but once I put something on it, it would lag the other cylinder and stop short. Some cylinders can be rebuilt, but i couldn't repair mine as it was sealed, had to replace it. iirc, around $1200 per cylinder. I replaced both while they had everything disassembled. I would not put the lift under load and run the boat without the latch engaged.
 
searay40dad said:
...and you're sure you don't have any leaks from the cylinder itself or with any of the lines and fittings running to/from the pump either inside or outside of the boat? My lift is a Nautical Structures but TNT was put on a lot of boats in this timeframe. I don't think they started putting on GHS until '02 or later but someone will have to verify that. Put a call into SR and I'm sure they can tell you what it is if they put it on. When my lift was sagging to one side, I had a leaking seal. I could refill the fluid and raise it w/ no load but once I put something on it, it would lag the other cylinder and stop short. Some cylinders can be rebuilt, but i couldn't repair mine as it was sealed, had to replace it. iirc, around $1200 per cylinder. I replaced both while they had everything disassembled. I would not put the lift under load and run the boat without the latch engaged.
Click to expand...

There are no leaks anywhere in the system. I have been able to identify the system as a Nautical Lift. From what I can tell that is good news since TNT seems to be very troublesome.

i have same symptoms you had, will raise without load. The starboard side has always been a little slower but I never thought anything of it since it would come up all the way. I am convinced that I have an internal bypass leak in the cylinder and it will have to be replaced or rebuilt. Problem now is locating parts or replacement. Would you have any advice on that?
 
yes, very good news. this is a very well designed lift by a company who does a lot of davit/lift work for the luxury yacht, commercial and DoD industries.

I'd call the service dept at Nautical Structures. they were very helpful when I was troubleshooting my problem and had a couple of cylinders in my hands in just a few days. if they can't help you for some reason, I wouldn't think you'd have a problem locating a suitable replacement. there are a lot of people who build hydraulic cylinders for marine use and most boat yards have sources too. If you need a part number for your lift or the cylinder in particular, I have them in my paperwork at the boat (assuming its the same model). let me know and I'll dig it up.

http://www.nautical-structures.com/products/transom-lifts.html
 
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I have a GHS lift on mine and it was going up and down crooked but would latch on top.
I called GHS and they were super helpful! I needed to replace my proportioning valve at about $140 del. I was first instructed how to remove it and clean it to see if that worked before selling me the valve.

Hope this helps,
WarrenG
 
The folks at Florida Bow Thrusters and Nautical Structures were very helpful in trouble shooting the problem. It is definitely a cylinder problem - requiring replace or repair. Eric at NS said I could pull the cylinders and take to a shop for repairs but he also mentioned some cutting and welding on the cylinders - which I did not understand but given his apparent familiarity with my system, I have to take his word for it. That leaves me with more than a little concern with the final outcome.

Considering the hassles with removing the cylinder, then finding a shop capable of doing the work and having the parts, getting someone to wok on it in a timely manner, not to mention my marina having to block up my boat while all this goes on AND the fact I will be stuck on dry land for who know how long - I decided to bite the proverbial bullet and spend the money for new. Of course that leads to more problems in that the exact same cylinder is no longer available. There is a replacement, but I will have to do both sides - about $2500 for the pair. But, they will bolt right on and I can do the replacement with the boat hanging in the sling.

Having somewhat conditioned myself to spending large amounts of money on boating made this whole thing a little more tolerable, but not much. Thanks to everyone that commented.
 
Yes, their cylinders are sealed/welded and aren't easily repaired. You'd have to cut the end caps off to get to the rod, piston, wiper and seals then reweld the end back on. Unless you have some experience working with hydraulic assemblies I'd be a bit careful here. The lines may/will have air in them when you hook them up to the cylinders. When you operate things to purge the air, the cylinder rods could extend at different rates, not in unison or just erratically depending on how much air is in the lines. This could put the structure in a bind and/or put a lot of stress on your lift arms and points where the rod eye attaches. Getting things to operate smoothly and evenly might be a better job for the boat yard. If they screw it up or something starts acting strange later on, it's on them. Of course, being from Iowa, might be a piece of cake if you're an ol farm boy.
 
Here is a photo of the cylinder:

NSplatofrm cylinder.jpg


THe photo was taken for another purpose, but if you can zoom in on the right end of the cylinder you will see an end cap with the mount made into it. That end cap is TIG welded onto t he cylinder and the weld is visible just under the 90˚ elbow on top of the right end. From the description given, the cylinder is bypassing oil past the piston as it nears the top of its travel. To repair, you have to grind away the weld and pull the cap off the cylinder where you can remove the piston and pull the cylinder rod out of the closed end. From there it is a pretty easy task to get a hydraulic repair shop to repack (i.e. replace all the rubber wear parts) the cylinder. Reassembly is just the reverse of taking it apart but then you have to have a TIG welder reweld the end cap on.

This repair isn't without risks:
1. Too much heat in grinding off the weld or rewelding can damage the cylinder
2. Too much heat in rewelding can burn the new rubber parts
3. The problem may not be (but most likely is) the rubber o-rings & seals leaking, but the cylinder itself may be scored. In that case anything you do will be a very short term repair since the scores will just cut/wear the new o-rings and seals.

Doing the repair right takes some time and skills so it won't be cheap (unless you are a damned good TIG welder). Our dealer had one cylinder repaired about 6 years ago and had very close to the cost of a new cylinder in the repair so they deem it not worth the risk since there is no warranty on the repair but there is on a new cylinder.
 
Now thats funny
 
I also agree with Frank's analysis regarding repairing the cylinders. That said, it could be the cylinders leaking down but it could also be low pump pressure. Most systems have some adjustment on the hydraulic distribution manifold (the lines connect to it). Some don't and have to be replaced as a unit.

Lift systems use a pump/manifold system which equalizes the pressure between the two rams. If the pressure is borderline (which drops with age), the ram with the heavier load will sag. Pressure will be equal between the rams but it will not reach the top of its stroke because the pressure beyond the set point is bled off by the manifold.

It is easy to check with a pressure gauge equiped with a t fitting.

John
 
PlayDate said:
I also agree with Frank's analysis regarding repairing the cylinders. That said, it could be the cylinders leaking down but it could also be low pump pressure. Most systems have some adjustment on the hydraulic distribution manifold (the lines connect to it). Some don't and have to be replaced as a unit.

Lift systems use a pump/manifold system which equalizes the pressure between the two rams. If the pressure is borderline (which drops with age), the ram with the heavier load will sag. Pressure will be equal between the rams but it will not reach the top of its stroke because the pressure beyond the set point is bled off by the manifold.

It is easy to check with a pressure gauge equiped with a t fitting.

John
Click to expand...

Thank John:
What you're saying makes sense. Eric as NS said the switch the lines - Port to Starboard, Starboard to Port - and if the Starboard side continued with same problem it would be the cylinder and not the manifold. However if the pressure equalizes between the two ramps as you explained, it could be pump pressure. I guess I will find out as I ordered the two cylinders from GS. Given they (Eric) essentially did the trouble shooting, I should be able to return if I find that was not the problem. I just didn't want the boat pulled without having parts.

I will do the pressure test before replacing. Would you be able to expand on how to do the pressure test? As noted, my marina is not much help here so I am pretty much on my own.
Rick
 
Rick,

Did Eric recommend anyone who could give you a hand? The reason why is that even swapping the lines creates an "Exxon Valdez" moment with hydraulic fluid in the bilge. First you have to trace the lines so that you can see which ones are associated with each ram and then for each ram determine which provide "raise" pressure versus "lower" pressure. Eric may be able to give the directions on how to identify the lines and swap them without having to trace them out.

This is a critical step because swapping the lines so that one ram goes up and the other goes down is really bad.

Does your pump manifold have a gauge port on it? Some do and Eric could also tell you where it is. That makes the job a lot easier than opening a line and putting a gauge between the line and the manifold or the line and the ram. If you have a gauge port, ask Eric the size and then get a hydraulic gauge to fit it. You can get them on Ebay for $30 and they are a great investment you can leave installed on the manifold. It should read from 0 to 1000 psi.

Eric can give you the psi specification for your lift which will help answer the issue if it is the pump/manifold. If there isn't a gauge port, let me know.

-John
 
PlayDate said:
Rick,

Did Eric recommend anyone who could give you a hand? The reason why is that even swapping the lines creates an "Exxon Valdez" moment with hydraulic fluid in the bilge. First you have to trace the lines so that you can see which ones are associated with each ram and then for each ram determine which provide "raise" pressure versus "lower" pressure. Eric may be able to give the directions on how to identify the lines and swap them without having to trace them out.

This is a critical step because swapping the lines so that one ram goes up and the other goes down is really bad.

Does your pump manifold have a gauge port on it? Some do and Eric could also tell you where it is. That makes the job a lot easier than opening a line and putting a gauge between the line and the manifold or the line and the ram. If you have a gauge port, ask Eric the size and then get a hydraulic gauge to fit it. You can get them on Ebay for $30 and they are a great investment you can leave installed on the manifold. It should read from 0 to 1000 psi.

Eric can give you the psi specification for your lift which will help answer the issue if it is the pump/manifold. If there isn't a gauge port, let me know.

-John
Click to expand...

Thanks John:

Actually switching the lines was quite easy. I switched them where they come through the transom which was much easier than tracing and working in the tight area around the pump. Only had to catch a couple drops of oil. I have not yet checked the pressure but have new cylinders on the way. Eric was very helpful and in his opinion the problem is the cylinder. I will know in a couple days.

-Rick
 
Re: Hydraulic Lift Platform on SR410DA - UPDATE

Nightmare.....
I have finally completed the repairs and the platform is raising properly. This however did not happen without a great deal of stress and 2 pulls by my marina. Eric at Nautical Structures was very helpful through the process however he did miss one important step that could have saved me a lot of work. To his defense, maybe I should have figured it out on my own too.

After replacing both cylinders per Eric's recommendation (just south of $2500 for parts), the lift operated fine with the boat on land both with and without a load (I later surmised there has to be some additional twisting when the boat is in the water and not supports by blocks). The lift would still not go up far enough to latch with the boat in the water and my dinghy loaded. Checked pump pressure (no easy process) to assure correct pressure which was right on.

After further discussion with Eric, he advised that there could be a problem with the bushings. This is the point that I think he could have mentioned before or during the cylinder replacement. There are 40 bushings on the lift ($16.50 ea) and you cannot see a problem just by looking at them externally. So out comes the boat again and with new bushings in hand, I began the process of replacing - which is not easy. Once you pull a pin, then you can see the bushings with the problems. I didn't have to replace them all, about half were replaced. After discovering the bushing issues - which is what ultimately fixed the problem, I am not sure that I needed new cylinders as the new did not actually fix the problem. Operating mostly on the advice of NSI, I just did what they suggested and I should have dug a little deeper on my own. But as I mentioned, you cannot see a problem with the bushings until pull pins and I was intently focused on the cylinders.

So, my advise to anyone having a similar problem is check/replace the bushings before spending over 2 grand on cylinders. Or just contact me for a couple of used cylinders.
 
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