water ballast leak

I have an LS4A glider that has developed a leak in
the left wing. The bags do not leak and I have had
the bags out of the wing and checked for the cause
but cannot come up with the answer. If anyone has
had a similar problem I would like to hear from you.


thanks Bob Harvey

Bob,

I had an LS4 with a leak. Actually, several leaks:

1. If it still has the factory original shower curtain (tan) bags
(highly unlikely by now, but I guess still possible), then really make
sure they're not leaking. One of mine had a pinhole leak that only
showed up when I put about a 4 foot head of pressure on it. It was
very small, but over a couple of hours...

2. I also had a leak where the hose clamp attached the bag to the
valve. This was a simple matter for reattaching the bag with a wider
clamp and adding a layer of RTV sealant.

Items 1 and 2 contributed to water in the wing.

3. Finally, I had a leak through the dump orifice due to the valve not
seating properly. This was a nightmare job, requiring disassembly of
the valve through the root rib on the wing. It's a sliding ball valve
with a wide o-ring. IIRC, the o-ring on mine had somehow been pinched
and wasn't seating. I took it apart, greased everything up, and it
worked fine. It still helps to slap your palm over the dump orifice
after filling the bags to help seat the ball valve firmly.

Though item 3 wasn't an issue inside of the wing, it was a problem on
cool days where a brief climb above the freezing layer would result in
a little ice patch around the valve.

Hope one of these is the cure.

Erik Mann
P3

Robert Harvey wrote:
I have an LS4A glider that has developed a leak in
the left wing. The bags do not leak and I have had
the bags out of the wing and checked for the cause
but cannot come up with the answer. If anyone has
had a similar problem I would like to hear from you.


thanks Bob Harvey

I owned an LS-3 for many years, which has the same water ballast
system, I believe. [I was also a moderately willing participant in
Erik's "nightmare" job on his LS-4 ].

I've heard from other LS owners that the little rubber boot that seals
the valve pushrod where it enters the valve body can leak, either from
a crack or hole in the boot or from loose clamps at either end of the
boot. The difficult part of any work is getting the valve assembly out
of the wing. I can't recall the specifics but if you've had the bags
out of the wing, you've already conquered loosening the big nut that
secures the bag/dump tubing to the valve. The rest of the difficulty is
working nearly blind through the hole in the root rib to remove the
valve. No cutting required, just long skinny arms with powerful
fingers. I know the factory had at least one special tool (a
long-handled wrench to loosen/tighten the aforesaid nut) and there may
have been others.

One question I would ask is whether the leak occurs anytime water is in
the tank or only during filling/dumping? Is it better/worse when the
left wing is up/down/level? Etc. This could help indicate where in the
system is the leak.

Chip Bearden
"JB" ASW 24