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Fuel tank leaking through plate mounting screws/nutplates

G

ghatch

Active Member
Hi all,

I am having issues with fuel leaking through the screws mounting the float plate to the tank. Since my kit was a QB, I did not have the option of using sealed nutplates. I now have a conic leak no matter how tightly I tighten the screws. Is there any sealant that I can put on the screw threads (LocTite or otherwise) to prevent the seepage?

Thanks,
Gerry
 
I'd be interested in seeing how the fuel lube will work in the long term....I'd go ahead and re-install the screws, encapsulating them with pro-seal. Thousands are done that way, and you never have to worry about it again.

Paul
 
We used the Permatex Aviation Form-a-Gasket (sticky brown stuff) on the screws, nutplates, and cork gasket. No leaks in a year and a half on the RV-8. Also no leaks in 7 years on a similarly-prepped RV-4.
 
Thanks guys for the quick and varied solutions. I need some pro-seal on hand so, I think I'll start there.
Thanks again,
Gerry
 
Gerry
The proseal is the way to go, I put a little on the threads screw it in and then cover the head with a bead of the stuff. If you want to make it look neat as the sealer begins to set wet your finger (rubber glove maybe) with a little soapy water and push/mold the bead to a nice rounded dome over each screw.
Jerry
 
Fuel leaks

For my 6A, the fuel system is the weakest link. In the course of removing the slosh, I cut new access ports in the rear tank wall. I installed the stock cork gaskets with 'fuel lube' and they held so far. The rubber gaskets for the fuel senders leaked when installed with the lube. I must have torked them too much. I removed the rubber gaskets and prosealed the senders metal to metal. On the up side, I can remove a tank in 40 minutes but I don't enjoy it as much as I used to. The old cork was seeping very badly at 10 years and 700 hours.
 
Cadstat said:
...In the course of removing the slosh, I cut new access ports in the rear tank wall. I installed the stock cork gaskets with 'fuel lube' and they held so far...
Click to expand...

John,

I just cut four access holes in the rear wall of my RV-4 left tank. I have a number of leaks and figured it was best to open the tank, clean everything, then pro-seal all seams. I cut four plates to rivet over the holes, and was going to pro-seal metal to metal. I am unclear from your comment above whether you used the cork gasket on the rear wall access ports, or on the rib access hole and fuel sender hole. If on the rear wall, can you elaborate on why you used cork instead of pro-seal the covers on?

Thanks,
 
Gerry, before you break out the proseal, I am not clear from your question whether you mean the large plate with the cork gasket or the small plate with the fuel sender and synthetic gasket. If the former, while I have had no problem with mine using Fuel Lube, many people get good results using proseal. On the other hand, I don't think I'd want to glue the senders themselves in, though I notice the instructions for the RV-10 tanks tell you to do exactly that. My technique with the screws and Fuel Lube is to get some on the screw threads and under the head, but not on the head itself (or the screwdriver will have problems). It doesn't take a big gob, just enough to seal under the head. Also, don't squeeze your gaskets to death. That doesn't make them work better, it makes them work worse.
 
Thanks Pat. I meant both plates. I ended up putting proseal on all the screw threads. It's been a couple of weeks.... problem solved.
Gerry
 
Pro Seal gun / Tubes of Proseal

These are the cat's meow if you never used them before. Tubes of both parts of the proseal in one tube cost about $20 bucks and you have the correct proportion in the tube. Very similar to a caulk gun and caulk.

Wish I'd use them during my initial build!
 
I have fuel leaks on both sides on my -6 from both the fuel tank end plate and around the fuel sender. This airplane sat with no/minimal fuel in for a year or more, I think the gaskets just dried out. Looks like they were assembled with no sealant on.

This is what I'm planning on doing, please correct me if this is not the right procedures:

-Drain tank
-Remove sender
-Remove end plate
-Clean up mating surfaces with acetone and inspect for any nicks, deep scratches etc
-Apply light layer of proseal on outside of tank where end plate sits
-Apply light layer of proseal on the gasket, both sides
-Apply light layer of proseal on the face of the end plate and reassemble
-Same with the fuel level sender

Questions:
-Is there a torque value for these or is it a case of "tight is tight, loose again is too tight"? I realize with gaskets they don't really need to be cranked down as it will cause the gasket to tail up, split etc

-My feeling is the little bit of sealant that gets on the bolt/screw threads as I reassemble is sufficient to seal. Correct?

-Is the 3.5oz tube going to be enough for both sides plates and senders?

-Are these the right parts:
http://www.vansaircraft.com/cgi-bin/catalog.cgi?ident=1328713862-372-30&browse=misc&product=t-cover
http://www.vansaircraft.com/cgi-bin/catalog.cgi?ident=1328713862-372-30&browse=misc&product=f-385

Thanks!
 
Old thread, perpetual topic

flion said:
Gerry, before you break out the proseal, I am not clear from your question whether you mean the large plate with the cork gasket or the small plate with the fuel sender and synthetic gasket. If the former, while I have had no problem with mine using Fuel Lube, many people get good results using proseal. On the other hand, I don't think I'd want to glue the senders themselves in, though I notice the instructions for the RV-10 tanks tell you to do exactly that. My technique with the screws and Fuel Lube is to get some on the screw threads and under the head, but not on the head itself (or the screwdriver will have problems). It doesn't take a big gob, just enough to seal under the head. Also, don't squeeze your gaskets to death. That doesn't make them work better, it makes them work worse.
Click to expand...
Quote: We used the Permatex Aviation Form-a-Gasket (sticky brown stuff) on the screws, nutplates, and cork gasket. No leaks in a year and a half on the RV-8. Also no leaks in 7 years on a similarly-prepped RV-4.

Found this post from a couple of years ago about using fuel lube (ezturn) to seal the 8-32 screws on fuel tank access covers.

Can anyone offer a pirep on the long term effectiveness of fuel lube and/or Form-a-Gasket, vs o-ring screws or just prosealing over the screw heads? If you ever need to re-enter the tank, cleaning up the external proseal is not fun (I'm doing it now, on 20+ year old tanks).

Has anyone who used either compound on the screws, run auto fuel with or without ethanol?

I'd like to avoid the mess of proseal and the expense/delay of buying o-ring screws.

Thanks,

Charlie
 
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