Fuel tank leaking through plate mounting screws/nutplates

[flion]

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.

[ghatch]

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

[Vern]

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!

[walkman]

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/...roduct=t-cover
http://www.vansaircraft.com/cgi-bin/...&product=f-385

Thanks!

[flion]

If you are going to use Proseal, ditch the cork gasket.

[rv7charlie]

Originally Posted by flion

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.

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