plastic gas tank warpage

hey guys, have any of you had this problem? My jeep came with a plastic gas tank. The tank is warping so that the top of the tank sags more than an inch and a quarter. This kinda messes up the fuel gauge. is there a fix for this ..... besides replacing it with a steel tank?

 

I believe that MTS is the usual supplier for these tanks. If this is an MTS tank, you could give them a call or send an email and ask if they can help you.

One of two things may be happening. First, this may be the normal shape of the empty tank, and the weight of a full tank of gasoline pushes out the sides and puts the top in tension, raising the sender. Or, it could be that the strap is squeezing the tank, and without a full tank of gas, the top is being pushed down.

If it's the former, you could put a brace across the top of the tank that holds the sender up and level.

 

Mine did the same thing. Probably typical of the plastic tanks. I made a bracket that mounted to the sender housing and lapped over the tank strap. Helped some but not perfect. I just have to live with it. Seriously considering lining my old metal tank and putting it back in.

 

Just a wild*ss thought... How about opening the sender port and wedging a spacer, jammed inside the tank, to support the top? A vertical leg, perhaps a section of ridgid plastic pipe or some such.

 

If that hold down strap is to tight that would happen. Its a easy fix, Remove the strap drill a hole in it lining up with one of the holes on the gauge reinstall it with a longer screw . this might give the tank a little more support. If the strap is flimsy just add a 8" long piece of flat stock on top of it to give it some added stiffness..my $00.02>>>>>>>>>>an yes i agree it should not happen, but it did<<<<<<<<

 

I have seen gas tanks collapse because they were not properly vented ?

 

thanks for all of the input guys. here is a little more info. the tank was only bowed down less than a 1/2" when dry. Now bows down when full of gas. Yes, I thought of the vent issue, but my cap does not seal well. My fear of anything attached to one of the screws in the sender is that they are small and would just strip out of the plastic.

I really like the idea of putting some PVC pipe in it to hold it up. I will give that a try and let you all know how that turns out.

 

As long as you can get the brace clear of the sending unit float swing and can somehow get it to anchor in place I think that would be an excellent way to correct this problem.

 

I'd suggest putting a piece of your shoring material in the gas you will encounter before doing this. That way you know whether it will deteriorate before potentially having issues.

 

Iv got two and havnt had this problem but my straps are pretty loose. Id put a few metal pipes in there to keep it up. thick and round ones so they dont fall over. And make sure its venting but by the looks of those straps I think thats what caused it

 

That would be a much better choice

 

>>>>>>>>>>>>>>>>thanks for all of the input guys. here is a little more info. the tank was only bowed down less than a 1/2" when dry<<<<<<<<<
Here is the problem, The sides are bulging out, an are causing the top to draw down. I would treat the cause. use some wood , say oak, an strap it to the sides of the plastic tank . this should stop the flexing...

 

well, the spacer wedged inside the tank did not work.
it was very hard to pry the tank upwards while pushing the PVC back away from the 1.5" diameter hole. The PVC ended up falling over inside the tank. Now it is just floating loose inside the tank and I cant find it..... not that I would be able to fish it out anyway. Oh well, I tried.

 

Sorry it didn't work. But those all sound like problems that could be solved.

 

I suppose that there are very good glue to stick to pvc.
Why not fix 2 or more screw to get it at the good shape? Of course must be a good glue.
Easy to make, a screw, a part above to fix and turn until the good shape; needs some screws in plastic too...