Inboard fuel tank

[jhickam]

Skyking

Well we got the inboard tank removed and and it was cracked as we thought it would be. We had to remove the top fairing of the boom to access the hoses and tubing between the inboard tank and the middle tank. We hope to have it flying in about a week with any luck. One problem with removing the top of the wing over the fuel tanks was that at a previous time somebody drilled a few of the screws and broke off screw extractors in the screws. The best thing I found to do was to drill out the broken extractor with a small masonary bit with a sharp cutting edge ground on it. You must use a green stone to grind the carbide on the masonary bits or a diamond wheel.

Thanks to everyone for the help.


Jim
N1871M

[GMAs]

hate to say it... but, you have to cut the hoses ... to get the tanks out... else you will bend the fittings that are welded on the things... it works the best... using a hacksaw blade by itself... and making sure you don't get the fitting on the tank... split the hose...

They get hard with age and you can't get them out any other way... now when you put them in...use new hoses and lots of engine oil... on the inside and around the fittings... I use a mixture of 50/50... engine oil and stp...and makes the hoses slide on...

On the inside tank... their are some little buttons on the underside of the wing... that we used to call chassis plugs.. then you reach in with a screwdriver and undoo the clamp....

Now when you go to put them in... or take them out... start with the outside tank and work towards the wing root... and when you put them back.. start on the inside one and work out to the tip... even though you only have to remove one tank... it is a lot less time to break them all off and re-do them... with new hoses...

AS to tightening the clamps.....Don't go using a lot of pressure on the clamps... the hose clamps will make a flat spot on the inlet/outlet fittings... try and put the clamp back exactly where the old one came out... and when you tighten it up... only 1 to 1.5 turns after tight... only....

You can always go back and check it if its leaking and tighten it up.. but, if you do too much... you will crack the fitting and then you get to take the tanks back out again...

As to the gaskets up on top for the inspection cover... and fuel sender... New...New... new... and use the right sealant... and torque on the bolts and then safety wire.. as you can't do it after the wing cover is back on...

While you have the inboard tank out... make sure you check the flapper inside that seals the pocket... you may want to replace it if it looks old...hard... or shows signs of cracking...

and use plybond on the cork tank straps... with masking tape...only... other stuff will cause the alu to start to corrode... clean the bottom of the wing where the tank sets is a good time while they are out... and when you go to put the tank straps back in... you don't again torque them up to where the tank starts to flex... just tight enough to keep the tank in place when empty... empty.... the wing top and bottom keeps it from going up and down... and if you torque the straps up too much.. your going to see the bottom of the wing start to show signs of stressing at the rib... (bending)

do not use actone or mek... on any of the wing pannels... as they have the hat section epoxied to the sheet... if you cause it to break free... you have more problems... so only stodard solvent or a product called aluaprep... and then real weak solutions... paint brush and lots of flushing after you get done cleaning the wing panels... just use water... it will delute out... and not hurt a thing... but, it will clean the alu....

Sorry that I didn't get back to you sooner... but, this is the only computer that seems to work... to get in to the board... the second and third one still can't make it... and even though I was reading the mail... could not get back to respond to you... but, were working on it... G.M>

By the way... here is a little trick we learned from boeing.... they dip the screws in zinc cromate.. the good stuff... and then put them in wet... it keeps them from rusting... and taking the cad plating off... when you run them in... then next time you have to take them out... they will come a lot easier... smile... G.M>