Changing Orings on Naiad 252 feedback assembly again???

[ron6785]

Question , when in port do you guys lock your stabalizers in place or just turn them off. The orings on the stabilizers are leaking again. I changed the entire feedback assembely on the Starboard side two years ago and it's beginning to leak and the port side is leaking. Wonder if when the unit is not pressurized if there is no oil at the ring ?? I'm talking about the Oring in the feedback assembly in the Servo Valve. DA had a BF,its leaking stupid of course there's oil at the ring. Anyway how often have you had to change them anyone??

 

[bobk]

Ron,

If I recall correctly, Niad recommends replacing the seals every two years. They also told me more use is better than no use because it reduces marine growth that can damage the seals. This would suggest that letting them flop in the slip is better than not. I've been doing mine every three years when I renew the bottom paint.

Bobk

 

[OBXTucker]

Doing mine every three years as well. I leave them on and let them flop around, but I don't recall reading that in the manual anywhere.

 

[sportfish 45]

He's talking about the hydraulic feed back unit not the sea water seals. Some of those systems have pilot checks that lock the fins on shut down. They are connected in the lines that feed the actuator. If you have them the fins are already locked on shutdown. Either way there should be plenty of oil to keep the FB unit lubricated. When you install the FB unit if you push it in to far you can damage the 0 ring. The bore could be worn or the oil could be contaminated.

 

[ron6785]

He's talking about the hydraulic feed back unit not the sea water seals. Some of those systems have pilot checks that lock the fins on shut down. They are connected in the lines that feed the actuator. If you have them the fins are already locked on shutdown. Either way there should be plenty of oil to keep the FB unit lubricated. When you install the FB unit if you push it in to far you can damage the 0 ring. The bore could be worn or the oil could be contaminated.

Right, I'm talking about the feedback assembly in the Servo Valve. Strangely it doesn't seem to leak when underway, or at least very little. My fins do not automatically lock down, you have to manually do it.

 

[ron6785]

Ron,

If I recall correctly, Niad recommends replacing the seals every two years. They also told me more use is better than no use because it reduces marine growth that can damage the seals. This would suggest that letting them flop in the slip is better than not. I've been doing mine every three years when I renew the bottom paint.

Bobk

Bob,I'm not talking about the sea water seals, I'm talking about the feedback assembly in the Servo Valve. Naiad want to sell you this dang little feed back spool for $ 280 . Not alot of fun to change as you have to take the Servo Valve off which means disconnecting all the lines etc.

 

[sportfish 45]

Right, I'm talking about the feedback assembly in the Servo Valve. Strangely it doesn't seem to leak when underway, or at least very little. My fins do not automatically lock down, you have to manually do it.

Just to be sure we're on the same page. I meant hydraulicly lock not the mechanical pins. If you have a vlave piped into the lines from the cylinder those are lock valves or pilot checks. They lock the fin on shutdown.

Leaking more when sitting is strange. Normally the feed back leaks when operating and not at all when sitting

 

[ron6785]

Just to be sure we're on the same page. I meant hydraulicly lock not the mechanical pins. If you have a vlave piped into the lines from the cylinder those are lock valves or pilot checks. They lock the fin on shutdown.

Leaking more when sitting is strange. Normally the feed back leaks when operating and not at all when sitting

Well my stab's move when shut off if there is wave action etc so there is action to the ram and feedback. Right I realize you ment hydraulicly and I don't have any kind of valve in th lines leading from the Servo to the Ram.

 

[SKYCHENEY]

Are you sure you did not nick the seals upon installation? As stated before, if you push them in too far, you will damage the seal. It is difficult to line up the set screw when you replace these, so you have to be careful.

 

[ron6785]

Are you sure you did not nick the seals upon installation? As stated before, if you push them in too far, you will damage the seal. It is difficult to line up the set screw when you replace these, so you have to be careful.

It's entirely possible Sky, however the one I replaced didn't leak after I fixed it, at least for a year. I really need to get down close and be sure its not leaking out of the ram. I'll do that tomorrow.

 

[jgbowers1]

Hello, New member and I ran across this very old thread. If any of you are still monitoring this, I have a similar issue. I noticed oil pooling on top of my upper seal wiper which appears to be coming from the feedback assembly in the actuator. That corresponds with having to add oil on a recent passage. I can confirm that it is Not coming from the hydraulic ram. In consulting the manual, there seems to be only one Oring on that assembly itself. Then, if I am reading the manual correctly, there are two more in the servo valve assembly. That looks more complicated. Should those Orings be replaced too? It looks like the servo valve however, can be removed in one piece with only four screws. then a set screw holds the feedback assembly in place.

Have any of you done that job and what surprises are in store for me? Do the hoses have to be removed? I think there is enough room to move the servo without taking off the hoses. Will the feedback assembly then push out? How much force would be required? Any pointers would be appreciated. Am I on the right track? I am pretty mechanical and can do this myself but would like to hear from someone who has done it. I haven't called Naiad yet as I fear they will try to sell me lots of high priced items I may not need.

Thanks

 

[SKYCHENEY]

Once the set screw is removed, the feedback assembly will slide out the back. Naiad will tell you to replace the whole assembly and not just the orings as the brass can get scored and still leak even with new orings. As stated, be careful pushing them back in that you don't go past the detent for the set screw as you will cut the oring.

 

[billwilletts]

Looks like I will be doing this as well. Do you have to remove the hoses and the 4 hex bolts holding the actuator on or is there another way? Would be nice not to have to remove all the hoses! what a mess. Photos attached.

 

[SKYCHENEY]

That looks like grease, not oil. That grease coming up is from lower shaft seals leaking. The water gets up there and pushes the grease up. Those lower seals should be changed every few years. When was the last time it was done?

The feedback assembly would just leak a little hydraulic oil (10w40).

 

[jmooney]

• I had to change both feedback units , but only once in eighteen years . I did have one start leaking again within months . I obviously got a small particle of grit in the system. The feedback rod had a tiny scratch which I would not have thought serious. But it was enough to cause a problem. I sanded out the scratch and then polished it . Got a new O-ring from Niad and it has not leaked since .

 

[billwilletts]

Thanks Jerry - the seals and all the bearings were replaced 3 years ago. They shouldn't be leaking but it's possible. I started looking for a leak because my reservoir lost a quart of oil during a 1 hour trip. Only leaks when I am using it and this is the only oil leak I have found. All hoses are new as well so I think this is the culprit. The shaft seals could be weeping as well. I am due for a haul out for bottom paint this winter.