Calling everybody that has switched out a gas tank on a 73-87
 

I know im probably gonna be told just to get under their and take it off but it never hurts to ask some questions
whats are the steps to take them off
my gas tank is been leaking and just got my new one in the mail
want to do it saturday, i dont have any help
its a 74 shortbed 16g gallon tank
i know the sender is their and the wires and rubber lines
whats the best way to lower it
can i lower the tank all the way to the floor with the sender still in it or would i have to lower the tank a bit then take the sender off then lower it?

Re: Calling everybody that has switched out a gas tank on a 73-87
 

i would take the bed off first then go from there. it's alot easier to see what your doing with the bed. you can take the bed off and replace the sending unit with in a coupla hrs. but if this is your first time i would take the bed off. then you can disconnect the sending unit and wires and drop the tank.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

i dont have a cherry picker or any type of forklift or hoist to help
i get what yor saying do, i wanted to get it all done in a day

Re: Calling everybody that has switched out a gas tank on a 73-87
 

i took the frame bracket's off put it all together put all the fuel line on first and put it in ?good luck

Re: Calling everybody that has switched out a gas tank on a 73-87
 

Sometime the lines on the left tank are long enough to allow the tank to drop down enough to make it easier to work with. If they have never been replaced they will hard as a rock and need to be replaced anyway so just cut them, unhook the ground from the frame and then unhook the sending unit wires. Replace the lines with some a little longer and be careful not to kink them when reinstalling. Also make sure it's as close to empty as possible.
Be sure to remove the two brackets that bolt to the frame with the tank, then you can remove the straps and swap tanks.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

It's my left drivers side tank by bracket yall me tank straps
This will be my first tank swap installing a new tank
Sender pretty easy to take off?
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Re: Calling everybody that has switched out a gas tank on a 73-87
 

Put a floor jack under the tank. Unbolt the brackets, then lower a little. Reach in and disconnect the wires and hoses. Then lower the tank all the way down. Sending unit is easy to replace once you can get to it. Basic hand tools, floorjack, and some patience is all you need.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

Exactly

Re: Calling everybody that has switched out a gas tank on a 73-87
 

This ^. I don't know why anyone would want to take 8 bolts off and then lift up and entire bed when they can take out 8 bolts and 2-3 hoses and have it out.

Yeah, with the bed off your not laying under the truck, but the tank is much lighter than a bed.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

That's a ***** of a job, grab 2 jacks, empty the tank, take off the skid plate, unbolt the gas tank and slowly lower with the jacks until you can take off the gas lines, replace sending unit etc...replace in reverse order, I've done this 3 times, not fun, but patience is key.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

DON'T PUT GAS IN IT! Make sure it is as empty as you can. Nothing worse than wrestling one of those things slushing around.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

I have changed out a tank on my 84 with the bed in place. You will have to lower it slightly and disconnect any wires and hoses from the top. Cutting the wires is not a bad thing, so keep that thought in mind. Wires are easy to fix and you do not have to kill yourself lowering the tank. Change out the fuel tank sender after it is on the floor.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

ughhhh. If you can take off the bed. I wish I had.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

If you take off the bed you risk messing up the holes in the bed or the bolts/nuts if they are rusted.

The way I did it (twice).

Get a couple of concrete blocks and short lengths of 4x4s and 2x4s until you have them stacked snug against the tank. Remove the bolts holding on the strap. Remove a couple of 2x4s from the rear of the tank. Now you can get up there and unfasten the hoses and the electrical connection on the sending unit. There is a ground strap on the frame with a big lock washer type eyelet that needs to be removed also. Remove 2 x4s from the front, then the back, one at a time, until you have the tank resting on the concrete blocks. Slide the blocks out from under the tank and remove the tank from under the truck. Use a flashlight and remove the hoses. Replace the hoses with new ones. It is a good idea to clean off the grounding eyelet, bolt, and frame surface where it mounts.

If you have a Spectra brand sending unit it will likely cause your gas gauge needle to bounce some when the truck is in motion (some say this is not true.)

Replacing the sending unit is easy. Just tap that tab sticking up (counter clockwise, I think) with a flat screwdriver and hammer until it backs off the tank - be gentle - you don't want to snap that tab off.

I think the sending unit will have installation instructions. I bought genuine OEM Delco o rings because they were rounded like a a traditional o ring and seemed to fit the groove better than the one size fits all type o ring supplied with the Spectra sender.

2 BIG CAUTIONS:
1) WEAR SAFETY GOGGLES, NOT SAFETY GLASSES. THE DIRT AND CRUD IN AND AROUND THE TANK WILL FIND ITS WAY INTO YOUR EYES FROM THE OPEN SIDES OF YOUR GLASSES. AT LEAST WEAR SAFETY GLASSES WITH SIDE SHIELDS.
2) YOU WILL GET VERY DIRTY - WEAR COVERALLS OR DISPOSABLE CLOTHING, OR CLOTHES YOU WILL EXPECT TO GIVE A HEAVY DUTY WASH AFTER THIS PROJECT.

This project is not especially difficult, just time consuming and dirty. If you take your time it will be easy - don't expect to rush through it - allow a full day. I always make arrangements for alternate transportation when I work on my truck just in case something goes wrong and the truck is inoperable.

I forget the exact sizes of the replacement hoses - a cheap digital caliper from Harbor Freight is always handy to have around to measure the nipples on the sending unit to get the correct size.

The LMC catalog has a good picture of the tank, straps, and hoses, wires.
I am attaching a pic of my 83 C20 dual tanks.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

Thanks everybody for the help, i will try to take pictures as i go about this
dont worry i would have either used up all the gas by then or it would drip out by then

piecesparts
Thanks for that tips about the wires, was looking between my frame and he gas tank and saw where the ground wire goes to the sender but theirs one of those yellow caps(for like household wiring? lol) thats probably a good time to fix the ground wire

tucsonjwt
You think the local auto parts store should have it
wha type of hose should i be looking for?

another question
could i still use my sender hasnt given me any problem or nothing

Re: Calling everybody that has switched out a gas tank on a 73-87
 

This is exactly what i did


http://forum.73-87chevytrucks.com/sm...ic,9294.0.html

Re: Calling everybody that has switched out a gas tank on a 73-87
 

i was googling for like a hour and never found this
maybe the way i worded it
that will help me out to along with all yalls great advice

Re: Calling everybody that has switched out a gas tank on a 73-87
 

As long as your bed bolts aren't junk they should come loose easy enough. At a minimum I would take the bolts out and secure the bed a foot or so high, at least the front. Watch cab and bumper clearance on the paint, duct tape over masking tape can help significantly. The clearance of the lifted bed is well wortht he minimal anout of time to create it. I have done many tanks/sending units in a lot of different set ups and in a lot of different ways over the years and when I can gain extra clearance I take the time to do it, it generally saves me time in the long run but it definitely save me aggreviation.

As with anything I try to think of projects I want to do in the same area so I maximize my efforts, for instance if I wanted to clean and coat the bottom of the bed it would be a great time to tackle both, pull the bed for access to the tank and flip it over and do the bottom of the bed while it's off. Maybe, frame work, shocks, wiring, brake lines, just what ever is int he area.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

It was quite easy for me to siphon as much gas as possible from each tank, support the tanks with wood blocks, and unbolt the brackets from the framerails (the strap bolts are too easy to break). Spray the bolts thoroughly with penetrating oil, or similar, prior to starting. I removed the attachment screws for the filler necks from the outside of the truck, and by removing wood blocks one at a time, I lowered each tank enough to disconnect the sender and hoses. Then I lowered each tank to the ground and slid them out from under the truck. You can remove, and install, the senders by tapping them in a rotating manner with the edge of a flat-blade screwdriver (it'll be obvious once you see them up close). I then washed each tank thoroughly with the garden hose, and allowed them to dry completely. Installation was easy with the help of my rolling floor jack, and I just reversed the process.
Here's the two 20 gallon tanks ready for re-installation:

Attachment 994053

Good luck, Frog!
Todd.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

One last thing: If you have the plastic tank shields that are under the tanks. It is good to keep them, they do protect the tank from road rash. HOWEVER cut some large holes in the bottom, so that they drain water out of them, the rust issue goes away if there is no wet dirt built up against the tank iteself.

I used a large hole saw to make my holes in mine---many years ago, no issues since.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

Just as an added measure of safety, I would use something other than a screwdriver, something made of aluminum or brass, or even wood if it will hold up. Steel can cause sparks, but aluminum won't.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

Good point on not using a metal screwdriver. A piece of hardwood like oak or maple will work.

If your sending unit is working just reinstall it. You might need to replace the o ring - just a few dollars at any parts store. Be extra careful taking that sending unit out of the tank and re installing it. It has fragile parts on it and a nylon sock on the end. If the sock is shot you can get a replacement.

I forgot about unscrewing the fuel inlet hoses prior to tank removal. I have a dump conversion so my fuel inlet hoses are just sitting there not hooked to the bedside.

When you take the short hoses off between the sending unit and the hard lines you can take those hoses to the parts store when you pick up a new o ring and just have the store clerk measure them up. Depending on your truck, I think you have 3/8", 5/16", and 1/4" hoses etc. As I said, the best bet is to measure the outside diameter of the sending unit nipples, but you can just match them up at the parts store - they do this all day at the store. The only issue is if the hoses are ballooned out of shape you have to guess at the true diameter. If your new o ring does not fit well, just clean up the old one and re install it. The aftermarket o rings seem to be extra fat and don't fit well in the factory recess.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

I just did my 83 and for me I lifted the bed with a block of wood and a floor jack. I also had to drop the tank. You can do it with just dropping the tank, but I had a very hard time getting the fuel lines back onto the tank pickup with the bed in place. At least on mine, you cannot get the tank pickup out without dropping the tank. The cab corner is in the way. It wasn't difficult, just kind of a pain. Make sure you tank the tank group out before you drop it. I had to solder mine back on because I broke the ground wire off before I realized it wasn't unbolted.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

My tank came with a oring
im gonna have to use scissor jacks my floor jack went out'
my truck didnt come with the shields

Re: Calling everybody that has switched out a gas tank on a 73-87
 

Granted your sending unit may still be good and you don't want to spend the extra money...BUT...once you figure out how much of an @$$ pain it is if you ever have to replace it, you'll probably want to do it now.

I'm a stickler for watching my pennies and not spending them when I don't have to, but it's just one of those things where you bite the bullet now and not have to worry later down the road.

As for taking it off, everyone's just about got it covered. Just have to get in there and do it. Take your time and don't get frustrated. It's been a while since I did it and the only mistake I made was either putting it back up backwards or putting the wrong strap on the front. We didn't realize it until we had it hooked back up and trying to strap it in place.

That's when it was time for a break, a cold one, and a new plan. The 2nd time around though it was much easier :D

Re: Calling everybody that has switched out a gas tank on a 73-87
 

im a try and take as many pictures or record as much of it as possible
patently waiting till sunday

Re: Calling everybody that has switched out a gas tank on a 73-87
 

http://i1105.photobucket.com/albums/...k/IMAG0765.jpg
http://i1105.photobucket.com/albums/...k/IMAG0766.jpg
http://i1105.photobucket.com/albums/...k/IMAG0767.jpg
http://i1105.photobucket.com/albums/...k/IMAG0768.jpg
http://i1105.photobucket.com/albums/...k/IMAG0769.jpg
the 2 scissor jacks i used to lower the tanks
http://i1105.photobucket.com/albums/...k/IMAG0770.jpg
http://i1105.photobucket.com/albums/...k/IMAG0771.jpg
http://i1105.photobucket.com/albums/...k/IMAG0772.jpg
http://i1105.photobucket.com/albums/...k/IMAG0773.jpg
This one with my finger is the direction you hit the oring to take it off, counter clockwise, clockwise to put it on
http://i1105.photobucket.com/albums/...k/IMAG0774.jpg
http://i1105.photobucket.com/albums/...k/IMAG0775.jpg
http://i1105.photobucket.com/albums/...k/IMAG0776.jpg
this was the reason i was getting dirt and rust in my filters this thing was barely holding on
http://i1105.photobucket.com/albums/...k/IMAG0778.jpg
http://i1105.photobucket.com/albums/...k/IMAG0779.jpg
http://i1105.photobucket.com/albums/...k/IMAG0780.jpg
just primered my tank on bottom black and etched the date on there, for future refrence or workers
http://i1105.photobucket.com/albums/...k/IMAG0781.jpg
http://i1105.photobucket.com/albums/...k/IMAG0782.jpg
jb welder my homeade strap extension, jb welded the nut onto the old thread and just used a new bolt
http://i1105.photobucket.com/albums/...k/IMAG0783.jpg
http://i1105.photobucket.com/albums/...k/IMAG0784.jpg

okay well i got my tank switched out saturday
everythings went good, except a bunch of little things
it was a pain to do my tanks bymyself
after i took my tank off
i was like im just gonna use my original sender
only to see that my filter was barely hanging on, so decided to get a new one
wanted to get it done today so i went to the local autozone only to find out they didnt have one and they could get it here tomorrow, they had one at a store 40 miles away so guess where i went, i needed to get this done so i just went and got it
primered the bottom of the gas tank black and ethced the date for refrence, so just incase i sell the truck or something happens where i have to part it out or whatever(knock on wood) the future owner would know
i guess my new tank was wider well the straps didnt fit
so i went to homedepo and got some 10mm bolts and nuts
jb welded them on they would have to do for now
its easier to install the tank with nothing in their lol
installed one new fuel line, didnt do the other one cus i cut the wrong one lol, but the other line looked good

im curious aout one thing i thought now that i installed my tank my gauge would work and it still dosent????

Re: Calling everybody that has switched out a gas tank on a 73-87
 

Did you hook up the sending unit ground and the sending unit wire?

I forgot my ground the first time, then while hooking up the ground I bumped loose the lead wire so it wasn't connected (it just slips over the peg on the sending unit).

Re: Calling everybody that has switched out a gas tank on a 73-87
 

Where in the world can I buy the straps for 87 3/4 ton, factory dual tanks? Please help!

Re: Calling everybody that has switched out a gas tank on a 73-87
 

LMC truck has them. Far as I know the straps are the same for either the 16 gal or the 21 gal

Re: Calling everybody that has switched out a gas tank on a 73-87
 

local parts stores .online places . lots of options .

they are riveted in place tho . so be prepared for a little work .

Re: Calling everybody that has switched out a gas tank on a 73-87
 

The bed bolts aren't that big a deal. If they're seized don't bother with horsing on em... cut em off and replace them.

One to three buddies and the bed comes off and sits on sawhorses in less than a minute. Costs some beer and maybe some hamburgers and potato salad.

I don't see the short ground wire that goes from the sender ring on the tank to the frame. The gauge won't work without it.

Your straps fit the old tanks so it's something about the new tanks or how they're installed on the hangers.
Look at the pinch welds on the old tanks. They're probably slightly bent on both sides at the hanger area to accommodate the straps.
The other thing that'll make the straps too short is using something that's too thick for anti squeak padding. I use a strip of 15# roofing felt under each strap and between the tank and the hangers. It's tacky and just thick enough to keep the tank from rubbing but thin enough that it doesn't interfere with the straps.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

The exception is that the square holes in the bed tend to round out. If the bed has been swapped out in the past, and a bolt is tight now, there's a good chance that one or more of the bolt heads will spin free. On an 80's Ford, I used an angle grinder to flatten the sides of the bolt heads, and had someone grab them with a vice-grip. With my Chevy, I tack welded the bolts to the bed.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

If you're worried about it weld a nut to the top of the bolt and use a box wrench in a section of pipe or a buddy on a breaker bar to hold em still.
I usually don't bother even putting a wrench on em... cut em off and re-install new bolts with Never Sieze... with hand tools. The T800 & T400 service manuals specifically say DO NOT USE POWER TOOLS on the body mount bolts and the bed mounting bolts. The same applies to the Squares. You round out the carriage bolt holes in the bed or round out the square sheet metal cage the body nuts sit in.

The flat belting or mud flap material or tire or whatever he used for insulator is why the straps are not fitting. I'd bet breakfast on it.

Re: Calling everybody that has switched out a gas tank on a 73-87
 

Dropped the tanks on our C30 by myself and will throw in another vote for sliding the bed back on some 4x4 blocks, loosening the wiring and hoses from up top, then bringing them down with a jack while hopefully they're empty. Like others have said, replace at least the sending unit sock while you're in there since they don't seem to do too well especially if the tank they're coming out of doesn't get used too much. Initially tried dropping and reinstalling without moving the bed, but leaving the fuel lines long enough to attach to the sending unit before putting the tank back up resulted in those lines being kinked and folded over themselves with the tanks in place. With the hoses the proper length (about 6" long), they're too short to allow the tank down far enough to secure them.