I have a leak in the left main fuel cell. Both Left and right fuel cells were replace last I can tell in 1986. I have the left fuel cell in hand, scheduled to go in the end of this month. My question is, should I replace the right fuel cell at the same time as it is the same age or wait until it fails?

Let your credit limit be your shopping guide.

William, depends upon your tolerance for having the plane down for maintenance. The only economies of scale are the travel time to and from the shop and disruption from any planned flying trips. With the black wing walk, the right one usually goes first but not always.

That being said, since I don't have much patience for that - when one main went, I did it immediately and the next annual I did the other three.

Thankfully I only have two fuel cells, plus tip tanks. I not sure how much I should trust a 26 year old fuel cell. This is my fist plane (only had it for 4 months). I have found a few things which needed attention before I could fly it.

I'm sure this is typical for a new owners, but it seems to need a small new fix every other week. I don't want to waste money, but not have too much down time.

She sure is fun to fly.

Ah yes - flying these wonderful planes sure makes the thoughts about spending too much money on them go right into the wind

The aux fuel bladders went 41 years and were not leaking when removed - however the plane was hangared when not out of town and always topped after flying and flown weekly - most of the time - all help to lengthen the service time of bladders.

I would probably wait. When they fail, they do not do it so quickly that you can't take a flight or two while the tank is on order. Any reasonably competent mechanic should be able to replace one in a day, unless something really weird crops up.

Hi William, I bought my Comanche 2 1/2 years ago and on the flight home the left tank would leak when topped. This was not unexpected as I had noticed the fuel smell and the fact that 1986 was the last rebuild for both tanks, same as yours. We replaced the left tank as soon as I got home and took the cover off the right side to check the top fasteners and tank condition and it looked OK! Webco had everything we needed for the replacement plus gaskets for the right side delivered UPS by the time I had the tank out and the bay cleaned and ready for install. 400 hours and 2 1/2 years later right tank still doing fine. Old 6659P has been hangared since at least '88 that I'm aware of, but that right wing walk is exposed to the sun when I'm out flying and at weekend events, which is a lot, because the old bird is so much fun to fly. So, I wouldn't give up on the right tank till ya need it. You'll probably smell it before you see any stains under the wing and Comanche tanks are fairly easy to change, so I'd spend the money on gas to get to all the Comanche Fly-ins that are just beginning for this season, but that's just me. If your mind is continually on that tank in the air you may want to take another tack. Ray B

If a new ( not overhauled) tank is replaced properly it will probably out last your flying career. If one is leaking now I would think that the other is not far behind. The only questions are new or overhauled, and now or later. I hartily recomend new, and if down time is a concern, and now money is not, I would do it now with new bladders. I found that Floats and Fuel Cells of Menphis were a bit less money, and were easy to install. I got mine through Airparts Of Fort Lauderdale. ( 954) 739-3575. I deal with Keith there.

I replace the one so far. It turns out it was an overhaul one at that, and it was the worst one the AP has ever seen. I looked at the cell. All the seems could be torn open the repair patches were pealing off.

Dear William,

My two cents worth: The biggest factor in fuel cell deterioration is whether the tank was left in a full condition of left less than full. The lower the fuel level, the faster the deterioration. That is why the tops tend to leak first and the fuel smell comes when the tanks are full. There is no way to determine how often the tanks were left down and how long in the past. That is history that you can never know except during the time that you are the owner.

The second biggest factor is the cleanliness of the interior of the wing cavity that the fuel cell is mounted in. It is very important that the cavity be very clean and that any edges are covered over amply with the special tape that cushions the outside of the rubber cell.

If a tank is not leaking, there is no reason to replace it. My opinion is that age of a tank is not nearly as much a factor as the previous two points that I made. I also have had good experience with Floats and Fuel Cells. They seem to have good fit and pliability for installation. That's not to say other companies don't make a good cell. It's just my personal experience with one company that I have dealt with. I wouldn't waste time or money getting rebuilt. Go for new and keep the tanks full as often as possible. If you buy during Sun-N-Fun or Oshkosh, you can usually get a discount. If you need it right away, bite the bullet and get the tank.

Sincerely,
Skip Dykema