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Fuel Leaks

T

Thor RV10

Active Member
Anyone have suggestions as to where or how I can efficiently fix or replace the black rubber gasket where my fuel metering is coming from? I wonder how long these gaskets are expected to last. I have pictures I took this morning, but I don't know how to attach it.

Thanks, Thor KAWO, Arlington, Wa

Dues paid 2019
RV10 963TM 820 hrs Hobbs since 09.15.2015
 
Thor RV10 said:
Anyone have suggestions as to where or how I can efficiently fix or replace the black rubber gasket where my fuel metering is coming from? I wonder how long these gaskets are expected to last. I have pictures I took this morning, but I don't know how to attach it.

Thanks, Thor KAWO, Arlington, Wa

Dues paid 2019
RV10 963TM 820 hrs Hobbs since 09.15.2015
Click to expand...

I purchased a 2015 RV8 in 2017, and had to replace the rubber gaskets in April of 2018. I replaced them with cork and some Permatex 80019 Aviation Form-A-Gasket. I've used Permatex 80019 for nearly 40 years on lots of motorcycles(an old Greeves that was a chronic leaker) and cars and it's never let me down. Great stuff. I pumped the tanks out, removed the wing root fairing, removed the sender, cleaned all the pro-seal off the area (being very careful not to get any in the tank) and put it all back together with the cork gasket and a thin film of 80019. Took and evening to do both tanks. Not a drop leaking since.

I'm pretty sure the instructions tell you to throw away the rubber gaskets. Not sure why the builder of my plane used them. If I can find a picture or two, I'll post them.

I used a pump similar to this one.
https://www.amazon.com/Sierra-Tools...red+fuel+transfer+pump&qid=1578782122&sr=8-11

Edit: Adding photos
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Over time the cork will eventually become saturated with fuel and leak again.

The permanent solution is to remove all gaskets, clean thoroughly and reinstall using only pro-seal.
 
Mel said:
Over time the cork will eventually become saturated with fuel and leak again.

The permanent solution is to remove all gaskets, clean thoroughly and reinstall using only pro-seal.
Click to expand...

Bummer. I thought I read somewhere that cork was the solution and that's what my A&P suggested. Two conditional inspections and everything looked dry. When should I expect them to leak again?
 
Northernliving said:
Bummer. I thought I read somewhere that cork was the solution and that's what my A&P suggested. Two conditional inspections and everything looked dry. When should I expect them to leak again?
Click to expand...

The next time it leaks, ditch the gaskets (rubber or cork) and just seal things with proseal. It will still removable, and will have a much lower probability of springing a leak.
 
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Northernliving said:
Bummer. I thought I read somewhere that cork was the solution and that's what my A&P suggested. Two conditional inspections and everything looked dry. When should I expect them to leak again?
Click to expand...

Maximum longevity I've seen for the cork gaskets is around 5-7 years.
 
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Mel said:
Maximum longevity I've seen for the cork gaskets is around 5-7 years.
Click to expand...

Thanks Mel. I'll see what they look like this summer at the conditional inspection inspection and may just replace as a precaution. Best to proseal in the warmer temps unless your work area is heated.
 
Mel said:
Over time the cork will eventually become saturated with fuel and leak again.

The permanent solution is to remove all gaskets, clean thoroughly and reinstall using only pro-seal.
Click to expand...

So to understand you correctly Mel you recommend ditching the gasket altogether and using a layer of Proseal in its place?
 
Mel: you suggested proseal instead of permatex. why? i know proseal is absolutley bullet proof but i really don't want to use it.

i installed the naked cork and the rubber gasket on my 7 (which should be very similar to the RV-10) and thinking about to do something before i put in fuel for the first time.

Permantex should work also and would be easier to remove later on for maintanance/modifications etc. or not? Is there anything against the idea to apply permatex #2 on both sides of the cork and rubber gasket?
 
As another data point: When I built my 8, I used the cork. At my last annual (December) I noted that the right wing was leaking at that area. I pulled the cover, removed the cork gasket, and used pro seal at the union and screws. Since it was cold, it took a while for the pro seal to cure...I ended up covering the wing/fuselage with a moving blanket and putting a shop light under it for warmth. After a couple weeks I refilled the tank and all is well. I will probably preemptively do the same thing to the left wing this summer when it is a little warmer. The task wasn?t that difficult...couple of hours work.
 
Cork baskets will work fine in this application - for a while, maybe a little longer if you schmooze it over with permatex, but it will leak eventually. Same with cork rocker box covers - eventually. Vans doesn?t even recommend using those rubber gaskets on the fuel tanks. While nothing is permanent (forever), proseal is the best way to go. It will probably outlast your ownership.
 
Based on this thread, I just pulled my rubber gasket out of one wing?s sender and replaced with tank seal. Will do the same to the other wing soon.

Given that the steel to aluminum joint, held in place with screws, is similar to the new joint I just created for the HotelWhiskey Extended Range Tanks (aluminum bung to aluminum tank held in place with solid rivets) I have a lot riding on this technique. But tank seal is what is specified by the HW ER folks, so there?s that.

Background: Been flying 9 years, 1200 hours with rubber seals. At some point it appears I had a slow leak that I must have fixed by torquing down the screws a bit. The original rubber seal I just removed was in good shape except for some tearing around two of the screw where I might have over-torqued it a bit. But no current leaking was evident.
 
KayS said:
Mel: you suggested proseal instead of permatex. why? i know proseal is absolutley bullet proof but i really don't want to use it.

i installed the naked cork and the rubber gasket on my 7 (which should be very similar to the RV-10) and thinking about to do something before i put in fuel for the first time.

Permantex should work also and would be easier to remove later on for maintanance/modifications etc. or not? Is there anything against the idea to apply permatex #2 on both sides of the cork and rubber gasket?
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Yes. The permatex will provide a good seal between the gasket and the surface. However, it doesn't help with the overall deterioration of rubber and/or cork material. When that happens, the leak is directly through the seal itself. These are thick gaskets with a substantial unsealed side.

Larry
 
Another very good, long term, solution that doesn't involve Pro-Seal is a flat Buna-N gasket (as opposed to natural rubber, Buna-N resists ethanol and 100LL) coated on both sides with Hylomar Blue or Permatex 85420 - comparable products and both are readily available and inexpensive (Amazon...). Unlike most gasket sealants, Hylomar Blue cannot be removed with alcohol, so resists all engine fuels, even ethanol.

An excellent sealant that can be removed later and cleaned up with MEK (if you can still get it) or acetone.

If you can't find a flat gasket already sized for your application, you can always buy a sheet of it (I recommend 1/16" for fuel senders) and cut your own.
 
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The pro-sealed senders can be removed by working a sharp putty knife into the joint. There really isn't a downside to using pro-seal.
 
Sam Buchanan said:
The pro-sealed senders can be removed by working a sharp putty knife into the joint. There really isn't a downside to using pro-seal.
Click to expand...

Aside from needing to have an unexpired kit on-hand and having to work with it, pro-seal does the job.

But a gasket and fuel sealant works very well too with less hassle at a lower cost. Life is full of options.
 
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Permatex 80019 spec

Found these instructions on the Permatex website for 80019.

"When used as a gasket dressing, spread product with a spatula to a uniform film on one side of gasket and then position it on the assembly. Coat the second side of gasket and re-assemble. Slower drying formula increases work time.

Assembly is operational after 4 hours, full cure is effective after 24 hours."

I used Permatex RTV 22071 for my truck thermostat. It suggested 24 hour cure, no leaks.

I used Permatex 81180 RTV for a Dodge transmission pan. It suggested 24 hour cure. No leaks.

I gather that the cure time is important.
 
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