I've read a bunch of the threads on gas tank cleaning. They all say to remove the sending unit. My problem is that the screws on mine are rusted in, and those little philips heads won't take much torgue. I may have to drill them out. Anybody got a better idea?

I thought about cleaning the tank with it in place, but I don't know what effect water, detergent, acetone, and all that stuff would have on it. Also I expect I'll need to recoat the inside.

Removed three gallons of the most vile looking and smelling 20 year old gas from the tank before dropping it. Yuck!

 

This may sound strange, but pour some coke on the screws. It may eat enough of the surface rust to let you loosen them.

 

Screw extractors. If they're that stuck, you'll want to replace them anyway.

 

Impact screwdrivers work really well usually for this kind of stuff. If you don't have one you can kinda replicate what it does, but usually takes 2 people to do it. One person turns the screw driver, while the other tapping away at it.

I have also had good luck with just vise grips before too.

 

/\ X2

I usually hammer my screwdriver into stubborn rusty screws before even turning them.

Sometimes this will break the rust lock (as I like to call it), or at the very least it gives the screwdrivers tip a bit better bite on the screw.

Penetrating oil can also be helpful!

Good luck!

 

I bought a Hitachi cordless impact for carpentry purposes years ago, and I use it for mechanic work more than anything else. I highly recommend them for any sort of rusty fasteners.


Isaac

 

mini vice grips.

 

I cut off the heads and pulled of the unit. Then used a vice grips to remove the screws.

 

Thanks. Lots of good suggestions, and a couple that can be attempted as fall backs if the first one fails. I've been spraying on penetrating oil for a couple of days. I think I'll try the impact driver first.

 

You can rent (at no cost) an impact screwdriver at most auto part stores. Works like a charm if you have never used one!

 

Here's an update. I got a hammer/drill driver, which worked fantastically drilling some holes in concrete for another project. All it did on the sending unit screws was turn the slots into smooth holes.

So we're on to plan B. Either screw extractors, or cut the heads off, remove the SU, and use vise grips. The latter has the advantage of maybe being able to get more penetrating oil into the threads, once the sending unit is out of the way. I'll sleep on it for awhile.

 

How about using a dremel and putting a slot in the screw or making two flat slots along the edge of the screw across from each other so that vise-grips hold better.

 

^--------+++++

That would be my next recomendation.

 

We ground the heads off of ours, lifted off the unit, soaked the remaining studs in penetrating solvent and then removed them with vise grips. This was the only way that worked, although it did work well. Remember it's a fuel tank, so watch out for sparks!

 

I was able to loosen mine by grabbing the heads with some small vice grips.
Learned that from RX7carl who used that method on troublesome carb screws.



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These SA sender units seem to suffer a lot from corrosion, more so than the FBs I think. I had the same problem and after stripping them, slotting them with a dremel.

I finally had to drill em out. I was still unable to remove all the studs but I got enough that I could refasten safely.

I used allen head screws this time so it will be easier to get it off if theres a
next time.

A solution from Re-Speed would be nice, either new tanks or a way to fix the
sender units.

 

Thanks for all of the good suggestions, but after trying Vise Grips, filing flats so I could use a wrench, screw extractors, etc., etc., I had to move on to plan F (for Fail) and just drill them out. I'll likely have to tap them all to a bigger screw size.

At least now I can move on to cleaning out the tank!

 

Hi everyone. Back again!

So here we are 6 months from the start of my tank cleaning project. After removing the sending unit, I found a thick mat of sludge/varnish stuck to the bottom of the tank. I added a couple gallons of fresh gas, and several bottles of carb cleaner, plugged up the holes and let it sit for a couple months.

That succeeded in breaking the mat free of the bottom, but didn't dissolve it as I'd hoped. A lot of shaking caused it to break up into some chunks that could be removed. I tried cleaning with Simple Green, which was useless. More water and lots more shaking kept breaking it up and getting more out. The big problem was the baffle in the middle of the tank, that prevented getting chunks to the openings where they could be removed.

Once I felt I'd gotten about 90% of it, I moved on to rust removal through electrolysis. Two weeks in the tank, removed the rust inside and out. Several more water fills and draining along the way allowed me to get 99.5% of the junk out.

On to tank repair and painting.