Under truck bed gas tank relocation

[gag1025]

I removed the stock gas tank from behind the seat on my '53 Chevy truck and bought a new rectangular shaped tank. The instruction to relocate the new gas tank say to bolt it to (hang it) under the frame and put a rubber pad between the tabs on the tank and the frame. Does it make a difference if I lay it in the frame, put the rubber pad in between and bolt it down?

[Rude Dude]

Posting a picture of what you are trying to do would really help

Originally Posted by gag1025

I removed the stock gas tank from behind the seat on my '53 Chevy truck and bought a new rectangular shaped tank. The instruction to relocate the new gas tank say to bolt it to (hang it) under the frame and put a rubber pad between the tabs on the tank and the frame. Does it make a difference if I lay it in the frame, put the rubber pad in between and bolt it down?

[mknittle]

Can you post some pictures? it's hard to say not knowing what the the parts look like.

That said it sounds safer the way you are thinking.I don't like the idea of the tabs under the frame in case a bolt comes out and putting the stress on the remaining tabs. if the tabs are on top of the mount and a nut comes loose the bolt may stay in the hole keeping the tank located. If the bolt comes out at least the tank is still supported.

[mr48chev]

I'd rather have the tabs supporting it on the frame rather than have it hanging by bolts below the frame. I think the main issue is will it clear your bed if it is higher in the frame and if there isn't any interference I don't see an issue with doing it the way you would like. Photos and more info sure would help though.

[gag1025]

I will do one better. Here is a link to what the truck frame looks like from the company that sells the tanks. This is the instruction sheet I was referring to. My truck frame looks just like the one in the two sets of pictures. The second set of pictures at the bottom shows the tank installed. Clearance is not an issue because the frame is probably no thicker than 1/4". The side tabs are half way down the tank and fit on the bottom of the frame which is channel which gives it a top and a bottom support attachment point.

http://www.docskustom.com/PDF_Files/...%20install.pdf

[mr48chev]

I think the theory for putting the tabs below the frame is that it would be possible to drop the tank without pulling the bed.

I think I would see if it fits and is simple to get above the frame so the tabs rest on the frame then if that is a go and there has never has been any gas in the tank I would consider having gussets welded on the top side of the tabs. Make sure you can get it in and out of the frame first though as the tabs may not fit inside the frame rails and that may be why it needs to be attached from below.

[BIG CHEVY 3600]

I didn't use the rubber under the tabs and really don't see a need for it. Most anything you use will deteriorate with time and the results will be a loose fit.

http://s729.photobucket.com/albums/w...CTHEIGHT-1.jpg

[gag1025]

I think you are correct in that they recommend that the tabs be placed on the underside of the frame member because it is easier to drop the tank if needed. I probably would never have thought of that until the day came when I had to drop the tank. I was telling the guy at Advance Auto (who has several hotrods) about the rubber pad and he said the same thing that he had never used a rubber pad but recommended that if I wanted to use a rubber pad that I use a 1" heater hose and split it (which would give me a little over 3 inch wide pad which is what I need plus the fact that this rubber pad would be much tougher than ordinary rubber. Doc (the guy I bought the tank from at http://www.docskustom.com/) recommends that I also use 2 medal straps around the tank attached to the frame members as added security.

[mr48chev]

A piece of smooth sidewall out of a junk tire makes a great insulator for things like that. The fabric helps keep it from pulling apart and it's free.

[gag1025]

Thanks. This is probably a better source of rubber than the heater hose and you can cut it to any shape and size you want.

[mr48chev]

I used to buy muffler hangers that had the rubber part made out of the sidewalls of tires. The bad part was that I was working in a Firestone tire store at the time and could cut the sidewalls out of fairly new warranty tires any time I wanted to.

[gag1025]

I have another question about the rubber pads between the tank tabs and the frame. Doc recommends using rubber pads. I have talked to many people who have used various after market aluminum and SS tanks and they indicated to me that they did not use rubber pads for various reasons and have never had any problems. Second question is this. Doc recommends using tank straps for added security. Several people have told me that they have never used straps because the 4 tabs are all that is necessary for support, plus the fact that the straps make the tank look bad regardless of what the straps are made of.

[mknittle]

Maybe get some gussets welded to the tabs. and use the rubber. whatever you end up doing I would use nylock nuts.

[gag1025]

Nylock nuts definately.

[OrrieG]

Bolted mine to the bottom of the frame rail with G8 bolt and lock washers. The receiver hitch shares a couple of the bolt locations for extra support. I did not use any separating material.

[gag1025]

Another question. My plans are to use 3/8 SS bolts and nylock nuts. Is it necessary to use grade 8 bolts or will the SS work just fine? My thought on this is that SS will not rust which makes for a neater job. I also realize that the SS has hafl of the strengthas the grade 8, but is the grade 8 overkill since there is probably not a sheer problem in this application.

[BIG CHEVY 3600]

Grade 8 are not necessary nor is any material between the tabs and frame if you have it bolted down snugly. Straps are also not necessary. A 20 gallon tank when full will weigh somewhere in the neighborhood of 20 X 6.175 lbs = 123.5 lbs not 500 lbs. Forget the straps.

[gag1025]

Thanks Big Chevy 3600. I actually went to Fastenal today and bought 3/8" x 1" SS bolts. He (manager who is a friend) was telling me that grade 8 used in this application is overkill, but that if I feel it necessary to use them and it puts my mind at ease then by all means use them. He also went on to say that the grade 8 bolt has a shear capacity of 130,000 -150,000 lbs. per square inch. whereas SS has between 65,000 - 100,000 lbs. per square inch. which will work fine for what I am using it for. I think I have those numbers correct but may be wrong, but the point is made. I also did not use a rubber pad nor the straps. The straps were an even bigger issue because they would make the tank look as ugly as some of my blind dates. Thanks because you verified what many have already told me.

[xaircav]

Got mine from Classic Parts, followed the instructions and used the supplied hardware.

[Kid]

just some food for thought..
1. aluminum against steel, dissimilar metals touching WILL cause corrosion in time, hence the suggestion for insulator between metals
2. Bolting the tank on with flanges nested to frame puts the bolts in a tension load, not shear (unless your rear ended). Use a quality bolt /nut that has proper tension strengh. I have built a few tanks with this style of mount, including the one mounted in my sons 71 P/U that was rolled during high speed & totaled in Colorado a few years back. The fuel tank survived the crash un scathed, but not much else.. my boy was not so lucky, but he's fine now.
Larry

[beanyard]

Originally Posted by xaircav

Got mine from Classic Parts, followed the instructions and used the supplied hardware.

XAIRCAV, would you go this route again? Does the tank have a pickup tube built in? What type of pump did you use?
Posted via Mobile Device

[xaircav]

Yes, it's a great tank. The mounting tabs followed the contour of the frame perfectly. The tank had pipe threaded holes for supply and return fuel lines, a top vent and a fill neck. I got a flush fill cap from Speedway or you get use a door like Classic products sells. I'm running the traditional engine driven mechanical fuel pump.

[Old Crow]

Hate to drag up another old thread, but we're also doing this mod to the '58 I have in the shop.
XAIR, where did you route your vent line? The flush fill cap I got from Brother's doesn't have provisions to run it to the filler neck.
If this was a wide bed truck I could just run it up inside the bed side., but not really any way to do that with a step side truck.

[gag1025]

Kid, I did go back and put some rubber pads (I made from a truck tire liner) between the frame and the tank.