The Brothers factory fit tank...
The Brothers factory fit tank in its gas tank package make up comes with all the 'goodies' such as the tank, straps, and AC Delco sending unit.
It's not high tech, it's not pretty, it's not 'trick,' in fact, you very rarely see it, but without it you are fooling yourself if you think you are going to make it down the road--and back home again! The gas tank isn't a sophisticated piece of hardware and you will probably rarely work on it accept for those obligatory repairs or to make a modification. Keep in mind, it's as important a piece of low-tech equipment there is, yet it will make all the difference in the world when it comes to your truck going anywhere.
On our Project Super Sub working on the gas tank was an after thought, in fact, if it wasn't for all the other work on the underside of the chassis it may never have been addressed. Our '72 Suburban was equipped with an aftermarket gas tank that held 45 gallons of gasoline. Yep, 45 gallons, that is approximately 315 pounds of gas when filled plus the inherent weight of the tank at nearly 100 pounds. In the greater scheme of things that's roughly 8 percent of the Subs total bodyweight. Again, it may not seem that much but it becomes apparent with all that weight hanging out behind the rear axle. Simple driving chores such as driving around town, making lanes changes, (hang on) a quick turn, or any abrupt motion and the 'tail wagging the dog' scenario comes to mind. The truck was a handful during the most mundane of driving, especially when it was about half-full and all that gasoline would get to sloshing back and forth. There had to be a fix.
A quick stop by Brothers in Corona, California, lead us to a fix that also proved to give us some options for modification we wanted to make to the truck later down the road--so to speak. Brothers offers a full line of gas tanks from custom to factory fit. There's a custom stainless steel or aluminum model for under bed installation on the '47-55 (first generation) or '55-59 pickups in a 20-gallon capacity, as well as '47-53 Suburban and panel trucks in a stock location as well as the '68-72 pickups in an under bed model that fills through the bed floor. According to the staff at Brothers, a tune-port injection fuel pump can be added to any of these custom tanks.
There's also a factory fit style for '69-72 Blazer's and Suburban's that holds 21 gallons, the one we selected, as well as new mounting straps which are offered as optional equipment. The tank is made from a polymer plastic thereby offering a lightweight replacement for an original tank. The gas tank package that we opted for (PN GTPDO72) included the tank, the mounting straps, and a sending unit. In our case we know that at some point in the future we will need to plumb the tank with a return line (fuel injected engine) and an external electric fuel pump to supply the EFI.
There are also '47-72 gas tank sending units from AC Delco that are sold by Brothers along with '47-72 gas caps (locking and non locking), a '47-72 gas tank filler grommet, a '47-72 gas tank seals, and a '60-72 gas tank covers. In other words, one-stop shopping for your gas tank needs.
How involved is the process--not very. Probably the single biggest thing to remember is to have as little gasoline in the old tank as possible when it comes time to switch. This makes the job a great deal easier and safer.
The Brothers factory fit tank that we selected was capable of using all of the factory fuel lines, filler tube, sending unit, and electrical connections (sending unit). Our swap took little over an hour from start to finish. The hardest part was getting the old tank out as its mounting points went through the factory wooden floor necessitating the removal of the interior carpeting to get at the mounting bolts. The Brothers tank is held in position via factory gas tank-mounting straps with several J-bolts and a couple of standard nuts and bolts.
Follow along with the photos that show both our Suburban and a '67 pickup with a tank mounted re-arward and under the bed getting the treatment. This is a very easy Saturday afternoon project that can yield lots of benefits down the road--and home again.
 Our '72 Suburban had an aftermarket...  Our '72 Suburban had an aftermarket tank fitted to it. We found this to be way too much gasoline and tank weight to drive around town and still have the truck handle well. Time to remove. |  Remember to detach all of...  Remember to detach all of the existing fuel lines, electrical connections, filler pipes, etc...before dropping the tank. Also, remember now is the time to check these components out and, if necessary, change them. |  Yep, first step is to remove...  Yep, first step is to remove the gasoline, good idea to make sure the tank has as little fuel as possible in it when the emptying process begins. |
 The AC Delco gas tank-sending...  The AC Delco gas tank-sending unit is available from Brothers separately and dialed into the particular truck, engine, and tranny combo that you have. In our case we needed a '72 unit for a V-8 with an automatic (PN GTSV872). |  Removing the old tank wasn't...  Removing the old tank wasn't difficult but it did necessitate removing the interior carpeting to get at the mounting bolts. We then had to fill the holes drilled in the factory wooden floor with a silicone to seal. |  The lock ring assembly starts...  The lock ring assembly starts by bolting the base plate (right) into position. The actual lock ring (left) sandwiches the gas tank sending unit to the base plate. |
 The rubber O-ring is critical...  The rubber O-ring is critical as it seals the sending unit preventing any leakage. It mounts between the sending unit and gas tank. |  You can use straight fittings...  You can use straight fittings on the side of the tank but you will need a 90 degree fitting for use on the top of the tank--necessary for clearance between tank and flooring of truck. |  The sending unit 'locked'...  The sending unit 'locked' into position with sending unit electrical leads in place. |
 The positioned brass fitting...  The positioned brass fitting will eventually be outfitted with a rubber hose that will serve as the tank's vent system when filling with gasoline. |  These holes come in the Brothers...  These holes come in the Brothers tank and accommodate the filler neck (far right), vent hose (center), and return line (left) ideal for a fuel injected engine application. |  Remember the 90 degree fitting...  Remember the 90 degree fitting we spoke about earlier? Here it's in position on the top of the tank and linked to a rubber hose which is part of the emission system on the '72 truck. |
 Since we aren't using the...  Since we aren't using the return line in-tank mounting point we have placed a plug to seal off the hole until future use. |  The tank mounting straps are...  The tank mounting straps are bolted to the frame with conventional nuts and bolts. From here the straps are formed around the bottom of the tank and then to the other side... |  J-bolts are used on one side,...  J-bolts are used on one side, allowing the straps to be cinched tight holding the tank in position. There are lips on the tank that position it between the truck frame rails. |
 This tank is set up for EFI...  This tank is set up for EFI with its fittings. |  The tank, while holding 21...  The tank, while holding 21 gallons, takes very little space underneath and makes a tremendous difference in the handling of the truck. |  An external Holley fuel pump...  An external Holley fuel pump is being used rather than an internal tank pump or a mechanical fuel pump (the latter isn't recommended for fuel injection). |
 Here's the same tank mounted...  Here's the same tank mounted within the frame rails of a '67 pickup. |  Here's an example of an external...  Here's an example of an external fuel filler neck. | |
| SOURCES |
Brothers Chevrolet & GMC Truck Parts
801 E. Parkridge Ave, Dept. CT
Corona, CA 92879
(800) 977-2767
www.brotherstrucks.com |