Fuel tank removal on the “B” model

[snellbob]

Has anyone ever needed to remove the fuel feed fitting in the fuel tank in order to remove the tank from the wing bay?
I have read thru numerous posts and don’t see that listed as a “have to”.
Having a tough time with clearance and the fitting ain’t coming out even after soaking overnite.

[jlwild]

There is a power point presentation in the MX Library that may help you. Do search “fuel tank removal” .

[snellbob]

Thanks Jim.
Yes I saw that excellent powerpoint presentation and thanks for putting that together. This project first started as just to remove the covers and replace the cork gaskets. Once the covers were removed I found that both tanks were chaffing hard on the inboard forward spar cap. It was then that I decided to remove both tanks and get a good look at all structure. My problem was a clearance issue with the right tank at first. I tried everything to remove the fuel feed fitting (penetrating oil, heat gun, hammer, etc) with no luck. Probably had never been out! Finally after enlisting a few more hands, the right tank came out without removal of the fuel feed fitting. Thankfully!!
Left tank, was tighter than the right side. NO WAY was it coming out without the fitting being removed! So finally after much mouse milk, heat cycles and precision tapping the left fitting broke loose and tank came out without too many new cuss words. I have some work ahead of me with a possible tank repair. Looks like someone over pressurized the right tank to leak check it perhaps. I’ll attempt to attach some pics.

Curious if anyone who has had the tanks out have experienced the tank chaffing from the spar cap. It could be that the clearance was never checked prior to strap tightening.
Thanks again

[n2582d]

Bob,
It looks like the plywood spacer, p/n 523524, located on the back face of the front spar, might be missing.

Spacer, p/n 523524

[ghostflyer]

This wooden spacer was rotten on my aircraft and has started corrosion on both tank and spar. Both[spar and tank ] were cleaned up and a strip of rubber was glued to the tank instead of the wooden block and due to the 2 retaining straps tank doesn’t move .

[DaveF]

That forward inboard corner is the tight spot. You have to put tape on the tank to avoid scratching it during R&R. Tank removal wasn’t the simple lift-out operation I expected.

Replacing the wooden block is also not easy. It’s held by two screws that insert from forward of the spar, and there’s no way to get at them.

[snellbob]

Well both wooden blocks were in place and doing there job. I can see contact points on both blocks where the tank was making contact. All blocks removed with minimal corrosion. Making new blocks from marine plywood as we speak.
My current dilemma is that both tanks were hitting hard on the fwd inboard spar cap angle as shown in previous photos.
Looks like I’m going to need either a serviceable right tank or have it repaired. Somebody over-pressurized it apparently doing a leak check it appears. Anyone have a serviceable right tank out there for a B model?
Looks to me also that the spar cap angle needs a little modification but I would not even think of doing that without Cessna engineering data. Perhaps there is some data published by Cessna on this but have not found it yet.

[jlwild]

Your fuel tanks rubbing on the spar is scary. Where the tank straps loose when you removed the fuel tank cover from wing? Did the wooden blocks have the rubber pads on them when removed from the spars? Snug tank straps and rubber pads on wooden spar block should keep fuel tank from shifting.

I would assume many of our club members planes have never had the wing tanks inspected. Due to our aircrafts age, perhaps this should be flagged for an item to inspect. So, Thanks for keeping us posted.

[snellbob]

The right tank (distorted one due to over pressure testing) had the fwd strap snug but the rear one was loose. All wooden blocks appear original with cork glued onto them. The left tank straps were snugged down securely but tank rubbing as well on spar angle. Yes, fuel leaks are never a good feeling! I found a post from another member in 2004 in which he stated he had to replace a tank due to this same issue and that the used replacement tank had a minor chafe area as well. I have also seen used tanks on Ebay that appear to have rubbed as well. This perhaps is just maybe an installation issue where the tank slips during tightening of the hold down straps? I’ll report back after I’ve re-installed the tanks but in the meantime if someone has a good right tank I may be interested in buying it. IF I cannot get mine back to a serviceable shape. Probably less expensive than a repaired tank.

[cessna170bdriver]

Sounds like a good subject for a 170 News article.

[GAHorn]

If that spar cap angle isn’t damaged... before I modified that I think I’d “modify” my tank inward a bit so as to avoid contact between it and the spar cap ( if the tank couldn’t be adjusted away from the spar.)
Those angles are known for intragranular corrosion and can be replaced while the tank is out.

[ghostflyer]

I used scotch bribe to clean the area where my “wooden”block was located and cleaned the area of potential contact with other parts of the internal wing structure . Then a coat of PR1440 B2 [BMS 5-26 type 2 ] was applied to all surfaces that had the potential contact with the wing structure . My wooden block was replaced by a block of rubber. So far so good after a number years . My rubber block was made from a blown out truck tyre I found on the side of the freeway.

[GAHorn]

I used scotch bribe to clean the area where my “wooden”block was located and cleaned the area of potential contact with other parts of the internal wing structure . Then a coat of PR1440 B2 [BMS 5-26 type 2 ] was applied to all surfaces that had the potential contact with the wing structure . My wooden block was replaced by a block of rubber. So far so good after a number years . My rubber block was made from a blown out truck tyre I found on the side of the freeway.

.... So.... I guess it could be said you’ve made that tire Air-worthy again.....