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RV-4 tank leaks

DR_Ranger

Member
Hello all,
first time posting on the active side. This week I bought a new to me RV4 with a fresh condition inspection by Base Leg aviation. Unfortunately upon landing back at home base the left tank showed leaks on the aft side of the tank, pics attached (According to the seller it was just repaired a few weeks ago). My hope is, that the the area in the 3rd pic is from the puddle of the first 2, not sure yet.

My questions for the ones that had to deal with this type of leak before:
What is the most effective way to fix limited leaks like that? Does one have to go inside the tank or can it be fixed from the outside?
Does the old pro-seal have to be removed or just cleaned before applying new sealant? Whats the best way doing this not causing damage to other sealing areas? Is there some wonder sealant that can be used for small leaks like that?
Any other hints?

Thanks in advance for any help!!
 

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I had a small leak similar to that. I was able to get away with using a wire wheel on a drill and scotch Brite pads to get the metal perfectly clean, then apply some proseal to the outside. So far so good. I figured I'd try that before I opened up the tanks. If it starts leaking again I'll have to seal from the inside.

Opening the tank is the correct way to do it, but it's also about a weeks worth of work and alot more opportunity to damage the tank.
 
Step 1

First thing I would do is pressure test per van's glove protocol.
Then, when the leak/ leaks are identified with soapy water, remove all old the proseal in that area, get it really clean, and re-seal. Then, after three days, repeat the pressure test.
 
Leaks

Might want to talk to the people at Weep No More in Minnesota. RV tank leaks are extremely common and a real aggravation…. I had several and eventually sent them my tanks. Over 5 years ago, no leaks.
I should also add that my tanks were sloshed and they cleaned that out so it was a no brainer for me.
 
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Dont tighten

Don't try tightening them. I did that knowing the risk and mine leaked worse after and I had to take them apart to reseal.:rolleyes:
 
Fixing it on the outside doesn’t work try this

Easiest and quickest is what someone mentioned earlier and try to fix it from the outside. It probably will start leaking again in a few months to a year. If so remove the tank and cut a hole in the rear baffle. It took me 30 hours total to remove the tank, remove slosh and proseal from the entire tank and reinstall the tank on my RV6A. You can redo the entire baffle or redo a few inches on either side of each leak. Instead of cutting a round hole I cut a rectangular hole. Before cutting out the rectangle I drilled a 1/2” hole using a step bit in each corner of the rectangle for each baffle. The reason I used a rectangular hole is to give me more room to work. Professional Strength Goof Off easily wrinkled the slosh in 20 seconds and was easy to scrape off. It will also soften proseal, but takes awhile, but you need a plastic putty knife to scrape it off a little at a time. Removing the proseal takes the most time and if I had to reseal an entire tank I would spend the $100 or so and buy the polygone to remove the proseal and save time. You can buy closed end Pop rivets but you still need a dab proseal on the end before inserting the rivets used to attach the patch plate on the rear baffle.

Chemseal is 1/2 the price of Proseal and is the same stuff. The best way to apply proseal is to use it tight rubber glove and use your fingertip. Don’t worry about being neat. The goal is to fix it right and not worry about making it look pretty.

To remove the screws holding on the tank to wing make sure you use a good quality #2 bit screw driver or bit on and impact screw gun. Stripping the heads and having to drill it out is a real pain.
 
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Thanks!

Thanks for all the input so far!!
My target is to get to flying and checkout ASAP, so I will try to confirm the leaks with the soap/balloon test. If the baffle is not leaking I will try to reseal the screw/rivet leaks from the outside with lots of pro-seal after a good cleaning. If the rear bottom baffle is leaking the size of the leak will have to decide if I use the vacuum method from the outside or if I go in.

Longer term I think I will try to build a set of spare tanks and/or get on the schedule for weep no more. Have been trying to reach them without success for the last few work days. Does anyone know there current prices and back log?

Thanks again!!
 
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