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Coupla Tank Leaks

StuBob

Well Known Member
Just finished my first fuel tank (RV8) and, not surprisingly, have a couple of leaks. One is at the top, outboard corner of the baffle. The other is around the fuel sender plate:

2016-08-19%252020.18.18-XL.jpg


Right where I'm pointing. It's an audible leak.

2016-08-19%252020.18.09-XL.jpg


On the baffle, I think I'm going to cut a hole in the end rib and access the baffle from there. Those ribs are very close together. I don't think I can make a hole in the baffle between them that's big enough for my hand. But is there any reason I can't slather some ProSeal on the outside instead?

On the inboard rib, that plate is ProSealed on good and tight. Can I make a fillet of ProSeal around the outside of it? I really don't want to try to get that plate off if I don't have to. I wouldn't know where to start.

Thanks in advance.
 
Repair

The best repair would be a hole and baffle plate. The tanks are off the plane. Best time to get it perfect. Vans sells them. Reach in and dab the proseal.
The the other option is to thin some proseal, pull a vacuum on the tank, apply and hope it sucks into the hole for good. Other probably have more ideas.
 
Why cant you just drill out a few rivets, slop some pro seal on there with a Popsicle stick, then rivet it back up?
 
You are way to clean!

Seriously, you need to have proseal oozing out from the plate and every #8 screw attaching the plate. I would consider removing the screws and heating the plate with a heat gun then pry the plate away, clean it up a little and be more generous with the proseal.
 
Why cant you just drill out a few rivets, slop some pro seal on there with a Popsicle stick, then rivet it back up?

I'm having trouble picturing this. Do you mean drill out the skin-to-baffle rivets, pry the skin out, and ProSeal in that gap?
 
The best repair would be a hole and baffle plate. The tanks are off the plane. Best time to get it perfect. Vans sells them. Reach in and dab the proseal.
The the other option is to thin some proseal, pull a vacuum on the tank, apply and hope it sucks into the hole for good. Other probably have more ideas.

On this hole and plate idea: Would you use closed-ended blind rivets or nut plates to attach the plate?
 
I had similar issues. I didn't want to cut more holes, so I rigged up some copper tubing on a grease gun (new and clean) with Pro Seal in it. I could bend the tubing where it needed to reach, and used an inspection mirror and a flashlight to see what I was doing to pump Pro Seal in the area with the leak. Since I needed at least three hands, I used some tape to help hold the light and mirror in place while I worked the gun.

Kind of hard to visualize, but it worked like a champ. And I just threw away the grease gun when the fix was done.
 
Fix it right!

I had the same exact problem. I researched the forums for days to find the easiest fix. Decided to use the "loctite" fix. It worked and was very easy to do. After a few days more I decided it was "to easy". Just as Wirejock says, the tanks are off the plane now, fix it right! Drill hole and use a cover plate on the baffle area. Remover the sender and reseal with a good bit more pro seal.
 
Thinned proseal/vacuum has potential for the back baffle, but be cautious with the vacuum. You can use a water column 'in reverse' to prevent pulling too much vacuum on the tank.

For the cover: To each his own, but for me, there's a reason it's supplied with platenuts & screws. I went off script when I reworked the tanks on my (purchased) -4. Bead on both; match head size dollup in each screw hole.
https://www.permatex.com/products/gasketing/gasket-sealants/permatex-permashield-fuel-resistant-gasket-dressing-flange-sealant/

Works fine; lasts a long time. And easy removal when (not if ;-) ) needed.

Charlie
 
idea for easy tank fix

Stubob - For the outside bay, top baffle / skin area ... as an alternative to cutting into the rib or baffle - I would get some A type 2 hr proseal as it is pourable and will flow into the cracks (spruce has it).

get a vet syringe from the local TSC, rural king or place like that. get a piece of leftover 1/4in aluminum tubing from your kit.

place the tank on your work bench so the leak area is on the bottom and you have access to the filler hole (tilt the leading edge of the tank up so the proseal will flow into the baffle skin joint at the lowest point). a borescope works great here or use a small mirror and penlight to see the baffle skin joint through the filler hole. if you don't have another set of hands to hold the mirror and light for you... tape them in place. I taped a small led penlight inside the tank just inside the filler hole on the top skin when I did this same fix.

bend the tube slightly to be able to touch the entire tank bay area upper baffle to skin joint through the filler hole and still have 6inches or so sticking out of the hole. fix the tube to your syringe with gorilla tape or similar. mix the sealant and apply it along the entire top seam of that bay over the current bead of sealant there. Get the top corner baffle joint good while you are at it. Pull a vacuum on the syringe and retract it out of the tank quickly. The Type A sealant is pretty runny coming out of the tubing.

the type A sealer will flow out into the seam to baffle / skin joint well. let the tank sit for a few days like that and it should be good to go. I fixed a top seam like this in the same bay area and it worked very well.
 
I've ordered a plate, but I'm pretty excited about this Type A ProSeal. Just ordered some from Spruce. I bought the pint, figuring the cartridge is only a 50% discount and there's a good chance I'll need it again.
 
Bluesky's trick for the back baffle is a good idea; I used a similar trick with Flamemaster pourable sealant (I used Flamemaster brand to build the tanks, too) on my -7 tanks. I forgot that you said the leak was at the outboard end, which gives good access through the filler neck. I used 1/4" nylon tubing with a coat hanger for a stiffener; the aluminum tube should be easier to position accurately.
 
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With my amazing $140 amazon-purchased borescope, I was able to find what looks to be the problem:
Photo%20on%208-20-16%20at%202.30%20PM.jpg


I'm pretty sure I can get the ProSeal back there with a syringe and some tubing. But I'm struggling to figure out how to spread it around. I need some way to manipulate this thing from 8" away through a 3" hole:
2016-08-20%252017.40.49-XL.jpg


I could do it with a colonoscope, but I don't think I could get away with borrowing one!
 
Had almost the same baffle leak on my -8 tank . I used a semco gun and cartridge filled with standard proseal, a piece of semi-flexible plastic tubing and a plastic threaded plumbing union which threaded into the end of the cartridge. Use a #10 solid copper wire as a stylet and practice before you mix any sealant. Use gravity to your advantage and it should flo out fine. Worked out well for me...Good Luck
 
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