TNT platform problems

[geriksen]

My new (1998) 500 Sundancer has a TNT platform that has problems. First it would not do anything at all. Now we got the pump working but the platform won't raise completely on one side and it intermittently hangs up on either side. It does something different every time you try it.
I have heard that these are junk and that TNT is out of business. I am starting to understand why.....
I am being told that the cylinders are bad and the thing to do is replace all six of them at almost 1K each!
This of course also means i have to re-haul the boat.
It almost acts like there is a large amount of air in the system.
Has anyone on the list had similar experience with these?

 

[Pirate]

My new (1998) 500 Sundancer has a TNT platform that has problems. First it would not do anything at all. Now we got the pump working but the platform won't raise completely on one side and it intermittently hangs up on either side. It does something different every time you try it.
I have heard that these are junk and that TNT is out of business. I am starting to understand why.....
I am being told that the cylinders are bad and the thing to do is replace all six of them at almost 1K each!
This of course also means i have to re-haul the boat.
It almost acts like there is a large amount of air in the system.
Has anyone on the list had similar experience with these?

I've not had direct experience with TNT, but my slip neighbor has a '99 540DA and he experienced similar problems. TNT is still in business, but under new ownership. I can't remember the specifics of his deal, but I seem to remember the new TNT owners distancing themselves from the prior owners and any warranty / liability, but I do think they were able to offer some consideration. Good luck.

I have a friend in Austin looking for a boat. Is your 500 for sale yet?

Best of luck,

M

 

[margarita jane]

Mine had a similar problem last summer only it was consistently low on port side....phoned TNT who were very helpful and said run it completely down and up 10 or 12 times to get air out of system and platform has been OK since...most rams can be rebuilt for a fraction of that price,hopefully TNT's can be rebuilt if necessary!...Tom

 

[geriksen]

Thanks Matt
my buddies are all teasing me about how this boat will be gone in a few months like all the others.
Officially, it is not for sale. But I do have a nice 40DA that is! And about 90 brokerage boats too....
Tell your friend to stop by, if he hasn't already. We were pretty busy last weekend.

I have looked at so many of these boats online and the ones with the TNT platforms all seem to have them sitting crooked or completely gone. The FL broker was supposed to have it fixed before it shipped but you can see how that turned out.....
Now it is my 6K problem. If I fix it before I get any advice here I will post the solution so maybe it can help someone else.

 

[geriksen]

Mine had a similar problem last summer only it was consistently low on port side....phoned TNT who were very helpful and said run it completely down and up 10 or 12 times to get air out of system and platform has been OK since...most rams can be rebuilt for a fraction of that price,hopefully TNT's can be rebuilt if necessary!...Tom

Thanks Tom
I feel like there is massive air in it. But it got worse every time we ran it up or down.
Now it is stuck halfway down. :-(
We are going to try it again in the morning when the fluid is cold.
Do you remember who you talked to at TNT?
I think there may be some type of bleeding procedure I should try first before I drop 6K
The TNT people I am talking to say that rebuild cylinders seldom work right.

 

[Four Suns]

6K? Heck... I spent 2K on my GHS hydraulic platform last year and there was nothing wrong with it.

 

[geriksen]

6K? Heck... I spent 2K on my GHS hydraulic platform last year and there was nothing wrong with it.

At this point I would love to spend 2K and have nothing wrong with mine. ;-)

And at 6K I am not including labor or the haul out.

I do own the yard/travelifts etc, and that helps but you should see what we have to do to launch these things during this drought. We trailer launch off the shoreline. It's nuts!
I'll post pics in a new thread.

 

[margarita jane]

Sorry, never got a name at TNT....let us know the fix...good luck!

 

[Stray Cat]

A 6 cylinder system with trapped air, I feel your pain. Not certain why you would get stuck in the mid point of the lift's travel though...unless the HPU got hot when it was frequently being run up / down.

What pressure does your hydraulic system develop when the cylinders are all dead headed (or stuck)? According to TNT's website, their online manual claims the relief valve is (or should be) set at 2500 psi....It would be good to know you have a stout HPU before replacing cylinders.

Just a few thoughts...

 

[fwebster]

I don't think your problem is on the pressure side. Your lift sounds like there is an air leak on the inlet side of the pump and it is pumping air into the system as you try to use it. Look for a pinched, crimped, cracked tube or fitting................unfortunately, a leak can be so small it will not leak oil out when at rest, but will suck air in when the pump tries to suction hydraulic oil.

Before you ask, I don't have one and don't really want one (guess why?), but I have tried to help others keep theirs operating or to get one home that broke while out on the water.

 

[Stray Cat]

Do the power units for these systems have a manual overide (like a hydraulic jack) incase the DC powered pump take a crap?

 

[Four Suns]

Do the power units for these systems have a manual overide (like a hydraulic jack) incase the DC powered pump take a crap?

Yes.

Doesn't do too much good though if a hydraulic fitting or something is leaking. I also carry a gallon of spare hydraulic fluid for mine. When the boat came from the factory, there were a spare set of exterior stainless lines tie wrapped to the inside... for good reason. These things are not maintenance free and mine has grease points/fittings on it....

I had mine completely taken apart, the metal parts sand blasted, primed and repainted, all the lines replaced, and everything greased up.

this was "before" with the stainless lines removed:

and after:

 

[Stray Cat]

I see a 3rd line on your smaller pic, does that run to a single acting cylinder? Those 37 deg. JIC fittings are notorious for coming loose or being overtightended. I have not used these in an industrial application yet, but it looks like they have merit if one of the flare faces gets scarred or the hose flare swivel were to be overtightended.

http://www.flaretite.com/

Thanks for the pics, I am always interested how fluid power is used in marine applications.

 

[Four Suns]

I need to find the bigger picture of the cleaned up one... Don't know what I did with it. Too many damn pictures.

The 3rd line goes to a locking cylinder that controls that stainless locking cam you see in the last picture. It is over a locking pin... so if the hydraulics fail, you can try and get it up on the pin/cam (I carry a come-a-long on the boat). I replaced both of the locking cylinders last summer as one one leaking...

I can't complain though. We really use and like the hydraulic platform. It's a great addition to our boat. It's just not "maintenance free"... not by a long shot.

 

[Jaws]

Gary,

You didn't mention the coolest factor of all with the GHS system.

Idling toward the mothership in your R.I.B./PWC you hit the remote switch and the platform lowers into the water allowing you to drive onto it. Problem is, the alarm sounds like the "Waster Management" truck emptying the local dumpster.

James

 

[geriksen]

Yes.

Doesn't do too much good though if a hydraulic fitting or something is leaking. I also carry a gallon of spare hydraulic fluid for mine. When the boat came from the factory, there were a spare set of exterior stainless lines tie wrapped to the inside... for good reason. These things are not maintenance free and mine has grease points/fittings on it....

I had mine completely taken apart, the metal parts sand blasted, primed and repainted, all the lines replaced, and everything greased up.

this was "before" with the stainless lines removed:

and after:

Thanks Gary but it looks like you have the newer design. Mine is the previous version designed by Mr. Rube Goldberg.

http://www.rubegoldberg.com/

 

[earthmover17]

Thanks Gary but it looks like you have the newer design. Mine is the previous version designed by Mr. Rube Goldberg.

http://www.rubegoldberg.com/

Geriksen,
I also have the rube goldberg design. I haven't had many problems other than it comes up lopsided. I just have to hold the up button until in levels. As i understand it has mutual pressure for both cylinders so if one has a slight resistance it will come up slower.
Did you get yours fixed yet? I would like to know how you come out.
Also how do you like the Detroits?
Jack

 

[geriksen]

OK
Here is an update.
The problem with the early TNT cylinders is that the seals dry out when the lift is not used for a long period of time.
(So if you have one cycle it up and down periodically)
The replacement cylinders and seal kits have seals made from a different material that solves this problem.
The reason my lift got worse with every cycle is that every time we tried it more seals fell apart.
After making, many, many phone calls, a different lift company referred me to a guy who specializes in these. In the next two weeks, I am going to fly him up here, haul the boat and have him rebuild all six cylinders.
This will still cost less than just the parts alone for new cylinders.

I will post the results after we get it done.

 

[fwebster]

That sure seems like an expensive solution to a fairly simple hydraulic procedure....i.e. rebuilding cylinders. I don't have a frame of reference for the cylinders used on a TNT lift, but on a Case backhoe, I can buy rebuild kits from Case for the 5" dia boom cylinders for about $75 ea and if I pay Case to rebuild the cylinders, it takes about 45 minuted per cylinder.

Also, most OEM manufacturers don't make hydraulic cylinders....unless it is Cessna or Beechcraft.......but I wonder about sourcing a generic cylinder for the lift by bore, stroke, diameter and mounting. A reasonably simple double acting hydraulic cylinder roughly the same size used on a lift is about $125.

Just a thought.........

 

[geriksen]

I thought the same thing. The ultimate solution would be to find the original vendor for the cylinders and buy new cylinders directly from them. Of course nobody is saying who that is.
Buying them from TNT was going to be $800.00 each. That is just the parts with no labor. This platform has SIX cylinders, where the newer ones seem to do the job with just two large ones and a better mechanism.
Florida bow thrusters will replace my mechanism with theirs for 25K. Ouch!
Buying new cylinders and having my own techs put them on would still cost me 7 to 8K by the time it was done.
I had the boat on blocks for a month and a half getting it ready for the lake. Unfortunately I waiting on a lying broker who was supposedly sending me a pump, or pump parts that he never ordered. When I finally gave up on him and fixed the pump myself, the boat was already in the water. He assured me that they had checked it out and the problem was in the pump. Of course, as soon as we got the pump working all the seals failed in the cylinders. This has truly been a nightmare.
If I had known the parts were never coming, I could have fixed the pump while the boat was out and I would have done exactly what you are talking about, remove the cylinders and try to source some directly.
Now, my main concern it not having the boat sitting back out of the water for another month. If you saw my other thread, you can see why I am so unhappy about pulling the boat back out again. At this point, to me 3K-turn key to have someone that knows all the tricks fixing all six cylinders is the best thing I have seen yet. Assuming he can do it.