Trying to solve a leak

[pirate]

Now trying to solve a WTC leak in my Ohio.

I've completely redone my O ring seals and the end caps. I'm sure they are good. Has anybody ever experienced SubTech control rod seals or shaft seal go bad and start leaking? They've been on there 4 years. I've got others on different WTCs that have been used a lot longer.

[thor]

Re: Trying to solve a leak

Pete,

I have had one that leaked on me after several years of use. You need to put some light oil on them every few months and they will last a VERY long time. Sometimes a small burr or foreign matter can get into the seal and scratch the sealing surface. They are very easy to replace.

[bigdave]

Re: Trying to solve a leak

Normally if you get any leaks it will be around the seal mounting.
If done right the seal assembly is installed in the opening with RTV so it can rock a bit with the servo arc.
After a while the RTV can leak overtime.
But they can dry out as well like Matt said.
I use STP oil treatment on my seals.
A trick Skip told me years ago.

Always use a synthetic oil too, never petroleum based oil.
I use the STP on my end cap rings as well.
BD.

[wlambing]

Re: Trying to solve a leak

Plumbers grease!! Dab a liberal coating around the outside of the seal and exercize the pushrod a few times. Make a good fillet of grease around the seal. Besides lubricating, it'll help the seal wedge itself around the rod. Helps the water pressure push the seal lip inward. And, it won't wash out!!!!

B^)

[pirate]

Re: Trying to solve a leak

Thanks guys.
I always use the STP oil treatment too. But it's not working any more.
Matt, how is it easy to replace? Didn't think you could get them any more. Do you have a guide on how to make one, or teplace the O ring inside?

I'll try the plumber's grease, Bill, if I can't make a new one some how.

[thor]

Re: Trying to solve a leak

Pete,

There are still, very much, available. I will pm you the website where you can order them. They are exact replacements and very inexpensive! They are quite easy to replace.

[raalst]

Re: Trying to solve a leak

sounds like you do not know what is leaking.

a) can you pressurize the wtc and see bubbles come out ? maybe fit a bicycle tire valve just for that purpose, as this ia a good pre-mission check in general.
b) failing that you could fill the wtc with toilet paper, hold it under for a while and see where it got wet.

then decide on a fix.

[pirate]

Re: Trying to solve a leak

I put it in the water close to the surface and turned on the power this time. While running the servo that controls the rudder I saw bubbles come out from the gasket. When I pushed it deeper, no more bubbles, but bringing it up showed water inside. The higher outside pressure should seal it, but that deeper water was able to force water in through it.

Pressurizing the WTC with SubTech BHS linkage seals would show leaks from all of them. There needs to be positive pressure from the outside for them to seal, that wouldn't work. But good idea.

I know I have a bad O-ring on that linkage seal now. Have to replace.

[pirate]

Re: Trying to solve a leak

Do any of you know from who I can order some new SubTech BHS-1 seals?

[bigdave]

Re: Trying to solve a leak

Mikessubworks still makes and sells them.
Greg in our subron ordered some a few weeks ago. BD.

[pirate]

Re: Trying to solve a leak

Part of the problem I'm noticing with this seal is the pushrod is scewing a little from throw to throw. The bad seal is allowing that--didn't start out that way. Doubt I'll have time now to get a new pushrod seal to install before Subregatta, so what I'm going to do is make another seal using an O-ring in urethane plastic and put it backwards on the inside to act as a guide for the pushrods to keep it going through straight. Then use Bill's idea of packing the outside with plumber's grease. This inside seal will also allow room between the inside and outside to possibly pack it with the grease, like a grease-packed shaft seal to hold the water out.

What do you guys think, good or bad idea?

[bigdave]

Re: Trying to solve a leak

Pete.
Sent you a PM. BD.

[raalst]

Re: Trying to solve a leak

This type of seal (Norbert Brueggen sells it over here) is not very forgiving on play.
if you can eliminate the play by e.g. bending/tweaking the pushrods then they are very good.

the solution you propose will be ok I guess, but it is just as easy to go with a bit of pipe on the dry side of the wtc
so that that pipe takes the sideways movement.
for a quick and dirty solution you could try to find a cable socket and simply mount over the seal and onto the pushrod.
graupner sells them, but they seem to be in use for bicycle and moped cabling too.
see http://www.quartel.nl/webshop/productde ... ?id=GR3356 for an example

another quick and dirty option is to try to limit the play on the dry side of the seal. I have no experience with it but it might be enough just to roll up a bit of (greased?) paper and slide it inbetween the seal and the pushrod (on the dry side).

the last resort is to tighen the nut a bit more so the O-ring grips the pushrod more aggressively (and with larger friction)
you might have done so already and therefore worn out the o-ring to become a ellipse-ring.

In any case have fun at the regatta !

[greg w]

Re: Trying to solve a leak

I have 2 spares in my box and I will be at carmel at the hilton thursday night. They're your if you want them. Greg

[pirate]

Re: Trying to solve a leak

Thanks Greg. Mike Schubar is supposed to be there. I plan on buying enough to cover my next model too from him. I he doesn't happen to come, then you'll be hearing from me.