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  #1  
Old 07-05-2017, 08:17 AM
sbalmos's Avatar
sbalmos sbalmos is offline
 
Join Date: Oct 2011
Location: Maineville, OH
Posts: 538
Default Tank removal - remove pushrods / access hole burrs?

Two steps forward, one step back. I now join the ranks of those who have to re-seal the rear baffle. That was a nice constant drip going yesterday, after filling with fuel for the first time. Admittedly, the first time any liquid had been in the tanks since the balloon, and a water, test four years ago when I built them.

So, now I get to remove both tanks off my wings, which are already attached to the plane. Meh. For the bolts that you have to reach over into the next bay over from the inspection plate blindly, it feels like my aileron pushrod is either in the way, or greatly hampers my ability to rotate a wrench. Should I just go ahead and remove the pushrod for now?

Secondly, when I cut the rear baffle access holes, I'm probably going to do one in each bay. When you go to deburr the drilled rivet holes for mounting the access plates, I was going to try and vacuum out as much as possible. But the first pressure test would be another colored water test, which would then slosh out the rest of the loose burrs when I drain the water. Then let the tank dry out for a few days, and then do another test with maybe a gallon or two of avgas, which would probably be discarded also. Does this sound appropriate?

Maybe a third fuel test after they're remounted to the wings, in case the re-bolting flexes something on the baffle? Not sure how to really test that without filling the tanks full again, since the rear baffle in a mounted position is basically "on its side".
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Scott Balmos
Cincinnati, OH
RV-9a slider - Started 1/12/12
N112SB reserved
IO-320 w/EFII and Catto 3-blade
Beringer brakes/wheels/tires
Dual G3X Touch (Stein's bankrupted me!)
Emp - DONE! (90%) (9 mos, 4 days)
Wings - DONE! (90%) (1 yr, 2 mos)
Fuselage - Almost Done
Finish - Engine Prep and misc
AT THE AIRPORT!!! (KHAO)
=VAF= 2016 paid up
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  #2  
Old 07-05-2017, 08:23 AM
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airguy airguy is offline
 
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Location: Garden City, Tx
Posts: 3,736
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I had to pull my tanks recently to change fuel sender types, I feel your pain. I didn't remove the aileron pushrod but I sure right on the fence about it, not sure if I saved time or not by just fighting through the tight spots versus pulling the pushrod. Access to the bolts will certainly be easier with it out, there's no question there.
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Built an off-plan 9A with too much fuel and too much HP. Should drop dead any minute now.
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  #3  
Old 07-05-2017, 08:55 AM
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RVbySDI RVbySDI is offline
 
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Location: Tuttle, Oklahoma
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Ok, since I have had the glorious experience of removing and "attempting" to patch my left fuel tank 6 times and "successfully" doing so a seventh time I believe I am qualified to give some advice on tank removal. First off, you do not have to remove the aileron push rod. You will be able to get into those bolts via the access plates. Granted there is nothing pleasant about doing so but it is doable. And trust me, the second, third, fourth and every other time after that will be even easier. I am sure though that you will wish to only do this one time.

There are a total of 21 bolts to get to. Some will be easy, some will be difficult. The best thing you can do is get good tools with which to do the work. I use 1/4 ratchets of various configurations. One of the best is a round knurled Kobalt 1/4 ratchet that you can hold in the palm of your hand and turn it. I bought this at the Lowe's aviation tool department. The other is a short "stubby" 1/4 ratchet (similar to this one) that is about 2" long. I am sure there are many like this to find. I bought mine from Bob Avery, who is no longer selling tools. Both are very useful, and might I say, necessary to do the job.

You will be able to reach in to all of the bays from the two access holes. I have a large arm that found the edges of the lightening holes in the ribs very uncomfortable. The thinner your arm the easier it will be for you. You are right, it is a blind activity. You will have to develop a good sense of touch to tell you what is going on. Make sure to not drop any hardware. You will be able to get them out if you drop anything by using a telescoping magnet but do your best to avoid that frustration. Know that each bolt should have a washer on it so make sure to hang on to those washers when pulling the bolts out.

As for getting debris out of the tank. If you plan on using Van's fuel tank repair kit you will have a nice large hole to reach in and access every inch of the interior of the tank bays. Oh yes, while talking about that repair kit, you will need a good hole saw that you will need to cut those 4" holes for the repair plate. I used an adjustable hole saw that I believe I also bought at the aviation tool department of Lowe's. You should not need to worry a great deal about having debris after you seal it back up if you reach in and do a very thorough job of cleaning up any debris before you seal it back up.

Lastly, there have been a great many discussions on this forum about fuel tank repairs. Many of them I have posted to. I have even started a thread in which I detailed some of my experiences (If you wish to read it go here). Do a search and you will find a great deal of information. Here is what came up when I did the search.

Feel free to contact me via PM if you wish to discuss any more details.
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  #4  
Old 07-05-2017, 09:16 AM
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sbalmos sbalmos is offline
 
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Thanks Steve! Hopefully it won't take 7 times for me.

I'm aware of the other threads and have read a good amount of them. Actually did so before fueling yesterday, in anticipation of something happening. There was obvious comfort in knowing ahead of time that this is an extremely common issue - once you get past the "oh ****" moment of seeing fuel dripping out from the skin-spar seam at a not-insignificant pace and the hour or so of draining 36 gallons into cans.

I've got long thin arms also, so reaching won't be a problem, and I don't mind doing things blindly. Thanks for the links for the tools. The palm ratchet I had never heard of, and Lowes doesn't sell them any longer. I'll see if Homeless Despot does, or something similar. Going to definitely pick up a stubby ratchet - been meaning to do so anyway. And yes, I was just going to end up ordering a number of the Vans patch kits, once I got the tanks off and got a proper look at the situation.

Hole saws are not a problem - Dad's an ex-industrial arts teacher. His basement shop is well-stocked.

Just another task... Was hoping to get to first engine start in the next few weeks, but probably not. Oh well.
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Scott Balmos
Cincinnati, OH
RV-9a slider - Started 1/12/12
N112SB reserved
IO-320 w/EFII and Catto 3-blade
Beringer brakes/wheels/tires
Dual G3X Touch (Stein's bankrupted me!)
Emp - DONE! (90%) (9 mos, 4 days)
Wings - DONE! (90%) (1 yr, 2 mos)
Fuselage - Almost Done
Finish - Engine Prep and misc
AT THE AIRPORT!!! (KHAO)
=VAF= 2016 paid up
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  #5  
Old 07-05-2017, 09:27 AM
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RVbySDI RVbySDI is offline
 
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Just a comment from someone who has been there. If I ever do build another RV fuel tank from scratch I will install the repair plates as part of the initial tank construction. I had a very hard time wrapping my brain around the idea of creating a container with a bunch of holes in it to hold a liquid. However, once I finally drank the Kool-Aid I realized these access plates should be the standard Modus Operandi for building fuel tanks.

Good Luck!
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  #6  
Old 07-05-2017, 09:30 AM
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sbalmos sbalmos is offline
 
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***AGREED PROFUSELY*** With as common as these rear baffle problems are, why not just make the rear baffle Swiss cheese to begin with (in a good sense)? My friend, who has a Diamond, had to have the equivalent done to his tanks last year. His repairman noted these kinds of per-bay access holes are actually now an actual orderable retrofit option.
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Scott Balmos
Cincinnati, OH
RV-9a slider - Started 1/12/12
N112SB reserved
IO-320 w/EFII and Catto 3-blade
Beringer brakes/wheels/tires
Dual G3X Touch (Stein's bankrupted me!)
Emp - DONE! (90%) (9 mos, 4 days)
Wings - DONE! (90%) (1 yr, 2 mos)
Fuselage - Almost Done
Finish - Engine Prep and misc
AT THE AIRPORT!!! (KHAO)
=VAF= 2016 paid up
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  #7  
Old 07-05-2017, 09:35 AM
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larrynew larrynew is offline
 
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Location: In New Braunfels, ist das Leben schön!
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Quote:
Originally Posted by sbalmos View Post
The palm ratchet I had never heard of, and Lowes doesn't sell them any longer.
Here's the link for the palm ratchet at Lowes. In-stock at my local store.

https://www.lowes.com/pd/Kobalt-26-P...ol-Set/3387780
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  #8  
Old 07-05-2017, 09:41 AM
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Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
Posts: 9,524
Default I know this will ruffle some feathers, but.....

It bothers me just a little to find that people consider this all that common.
There are literally thousands of RVs flying that have never had a leak from day 1.
If you pay close attention to building the tanks, leaks should be very minimal.
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  #9  
Old 07-05-2017, 09:49 AM
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sbalmos sbalmos is offline
 
Join Date: Oct 2011
Location: Maineville, OH
Posts: 538
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No offense Mel, and I don't want the thread to diverge - I've got the information I need. And as I mentioned in my first post, the tanks didn't leak - when I tested them after building them 4 years ago. And before anyone asks, yes I gooped on the proseal quite heavily when installing the baffle. I knew that was a problem area to begin with. What happened between then and now, I don't know. It's useless speculation at this point.

I'm human, a first-time builder, not a mechanic or aviation-related by trade or profession, I was paying close attention in building at the time, having educated myself of the pitfalls from this forum... something happened after 4 years. *shrug* "Stuff" happens.
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Scott Balmos
Cincinnati, OH
RV-9a slider - Started 1/12/12
N112SB reserved
IO-320 w/EFII and Catto 3-blade
Beringer brakes/wheels/tires
Dual G3X Touch (Stein's bankrupted me!)
Emp - DONE! (90%) (9 mos, 4 days)
Wings - DONE! (90%) (1 yr, 2 mos)
Fuselage - Almost Done
Finish - Engine Prep and misc
AT THE AIRPORT!!! (KHAO)
=VAF= 2016 paid up
Reply With Quote
  #10  
Old 07-05-2017, 10:58 AM
Michael Burbidge Michael Burbidge is offline
 
Join Date: May 2006
Location: Sammamish, WA
Posts: 537
Default Find where it's leaking...

I've had to remove my left tank twice. One leak was on the cover plate and one in the rear baffle.

I had an RV-expert and A&P friend help me fix the leaks both times. He used the tank test kit, (ballon, etc.) to find where the leak was. Pressurize the tank using the test kit, then use water and soap to identify where the leak is.

Fuel can wick like crazy. It is sometimes not at all obvious where the leak is.

The rear baffle leak was in the bay where the fuel fill hole is. My A&P friend was able to remove old, softened sealant, clean and apply new sealant through the filler hole. He fabricated some make shift tools. 100 hours later, the repair is holding up well.

I had blue fuel stains all along the rear bottom seam of the tank, as well as the inboard edge. It looked like it was leaking all over the place, but it turned out to be one small spot on the outboard bay.

I was very happy that we did not have to tear into the rear baffle!

By the way removing the 21 bolts, is not near as bad as it is hyped up to be, once you've done it. The second time, I had all the bolts installed in less than 30 minutes. There's only 2 or 3 that are painful, even with the pushrod still installed. I fretted over this for some time, and even hired my A&P friend to do it the first time. The right tools, as have been suggested is the key.

Michael-
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