Water Tight Floats

[ericfo]

I've probably posted the same question years ago, but I can't remember.

I am getting the 1800 amphib floats ready to put back on the Elite (it was 106F today in Redding, CA). So, I'm doing all the float maintenance work that I should have done long before it was 106F in the hangar.

Need to address a leak or two. What is the correct solution for sealing or not sealing the outer and inner float chambers where the lower main gear bolts attach? Since the bolts protrude into these small chambers and you have the nuts on the inside of the chambers, you get some water passing by the bolts and getting into these chambers. There are corrosion issues with these bolts regardless of proper solution to the leak problem, so I don't thing you smother the nut inside the chamber with proseal since these bolts need replacement from time to time.

Do I:

a) Just let the water slowly leak back out around the bolts just like it slowly leaked in?
b) Do I add a drain hole that lets the water get back out faster?
c) Do I add a drain hole and a little bilge-style half cover that are on some boats that helps suck the water out during takeoff run and in the air?
d) None of the above

Thanks,

Eric

N645E amphib and N112R

[irishfield]

I've never had any issues there Eric and I have left my airplane sitting at the dock for over 6 weeks before.

The way that goes together, the clearance should be so slight between the bolt and the spacer sleeve that with a good coat of grease on the bolt no water should venture sideways there. That only leaves the gap between spacer and the attach fitting for water to get in. Again the attach fitting should be a snug fit on the bolt too and grease in there should be sufficient as there is no where for it to go via water pressure due to the washer and nut in the small compartment.

So even if the water gets through all the above.. it then has the washer snugged on with a nut in that compartment. That bolt should be snug and the trailing arm and spacer should be filling the space between the two pick up fittings. If not machine a longer spacer to take up the slop. I can't remember if I bothered to bury the nut in sealant on the last set I built, but I know I did on the first set that were still in operation up until 3 weeks ago when a crane in Guelph put then to their demise lifting them out of the lake.

A thought if you're happy with everything in the wheel well, but are experiencing leakage into the compartment. Take the washer and nut off and see if there is any bolt shank available inside there. If not go up one bolt length, and in ether case find a rubber washer (or o-ring) that is tight on the bolt. Slip if over.. replace the washer (s) and tighten up. The bolts not to rotate anyhow. Snug it down and the rubber will seal the bolt shank to the inner compartment wall.

[irishfield]

BTW.. those little compartments should have drain holes at the fwd end that allow the compartment to drain into the step compartment.

[ericfo]

Thanks Wayne.

Not sure how tight the bolts were since the floats were factory built and it has been years since I initially removed them and reinstalled them.

I think it is time to pull the bolts out and see what I've got. I like the idea of plenty of grease and a rubber washer/o-ring around a longer shank bolt mashed by a washer and then the nut. Keep the water out, and then add small drain hole to the step compartment for small amounts of water that gets there from condensation or wherever.

Thanks again,

Eric

[Walter Klatt]

Eric, if this is the one on the side of the wheel well, I fixed mine about a year ago by just wire brushing off the old pro-seal and totally covering the bolt and nut again with a big glob of sikaflex. Has been good ever since. This is also the location where it has been recommended to add a doubler (I don't have it on mine) to provide more support to prevent flexing.

I notice now that my other side is starting a slow leak there, too, so may have to do the same with it soon as well.

My floats are 15 years old now, with over 1000 hours (and have never been off my plane), so can't really complain.

[ericfo]

Thanks Walter.

I did some front float gear maintenance today but after a few hours above 100F in the hangar, didn't have the desire to start in on the main gear lower attach bolt leaky issue.

Once I get in there and see what is going on, I'll have a better idea of whether to go washer, o-ring or Sikaflex. Don't have nearly the time of the floats as you, Wayne and others. They sealed fairly well for a few years, but now I come home to a steady trickle after some time playing on Shasta Lake or the Sacramento River.

Eric

[skidaddy20000]

Hello All,

The other day I finally got around to addressing a significant leak in the second from the front float compartment on the passenger side. I gently pressurized the compartment with the shop-vac, then ran the seams and rivets and pretty much eveyything else with soapy water, looking for bubbles. No luck. Any suggestions?

Thanks,

John

[Ray Mason]

You can try filling the compartment with water. wait a while and if you can't see anything take a colour paper towel and press it against the rivets and seams

[Ken]

Amphibs have that channel for the front hydraulic cylinder above the second compartment and water can sit in the back of it. I actually put a drain at the rear of mine.

Think it is the third compartment on mine that likes to drain water down the openings for the hydraulic hoses (rain) and also the spreader bar opening if I don't seal them.

If you put water in them I wonder if adding a bottle of food coloring or I think kid's use a water soluble finger paint. This comes to mind after chasing a fuel leak for too long. It was in a hot area that kept drying and leaving no trace at the leak source after shutdown, despite liquid fuel still dripping out of the airframe.

Ken