Lost Bear
11-13-2007, 01:32 PM
Recently I relocated the gas tank in preperation of doing a 4 link in the rear of my Solid axle Tacoma.
Although this seems as a straight forward modification, there possibly was some "new ground " broken with this project.
First order of business was to decide on an alternate location. It is easy just to throw a fuel cell into the bed and be done with it, but that is too easy! besides my bed is already getting cramped with a full size spare 37" tire, 20 lb Co2 bottle and an ammo box, not to mention my trail trunk that gets anchored to the bed when I go out.
the original goal was to locate the 22 gallon fuel cell over the rear axle. This would provide added traction by placing weight directly over the axle. Problem being is the plans for the 4 link calls for a panhard/trac bar which would directly intersect with fuel cell. Putting the cell further forward was not an option due to the drive shaft.
So with fear of immitating a 1971 ford pinto, the decision was made to locate the fuel cell aft of the rear axle.
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010485.jpg
Once the decision was made, and measurements were taken three times. The frame was begun. Original idea was to make the hanging cradle from 1.5"x1.5" angle iron supported by .75" angle iron, with the front "legs" being supported from my existing shock bar.
What we ended up with (extra stock from a previous build) was 3"x3" angle iron for the cradle. Although this did make the cradle heavier, it did provide more security in regards to the "Pinto factor"
I won't go into detail on how to weld up the frame or supports as most here know the ins and outs of faberication.
I will comment on the skid plate design and application. Since putting the tank behind the rear axle, there is a potiencial of loosing some departure angle (especially on linked rigs such as what mine is intended to become) So with that consideration, I wanted to make a skid that would be able to take the abuse. So I opted for 3/16" plate I found in the drop metal section of my local metal supply (drop metal is cheaper due to it being the yards surplus). So after adding a center support to the cradle, on the outside of the frame using a 1/2"x 2" piece of stock (will explain shortly) I tacked the sheet to the bottom of the cradle.
The reason the support was added to the outside of the cradle frame was so that without having to drill holes into the sheet metal I created a natural valley and gap for drainage,also keeping the support under the plain of the fuel cell so that it remained even. this support being made out of 1/2"x2" also provides a location to locate a floor jack if needed while working on the vehicle, not to mention allows for greater protection to the rocks.
The last comment on the cradle is this. Still being concerned with the "pinto factor" I used more 1/2"x2" stock I had laying around for the back side cradle hangers/supports as well as some excess cut from the bottom skid plate. This extra was welded to the hangers as well as to the angle iron to create a verticle "skid plate" for the back side of the fuel cell. So if a compact car does rear end me, they are not going to get to the fuel cell (I still drive this truck daily) nor will backing into that 3 foot boulder puncture the cell either.
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010490.jpg
After adding a cross member across the rear part of the frame, the basic frame work was in place.
Many have already asked me what I did with the fuel pump situation, since tacos have an internal fuel pump. Did I convert to an exterior pump mounted to a frame rail or some other location on the truck?
The answer is no! We used the stock fuel pump and placed it back into the fuel cell along with all the other stock components placed into the new fuel cell.
We cut a hole into the front left corner of the fuel cell and ran a galvanized elbow obtained from the local hard ware store, along with two electrical conduit nuts the same size. Placed the elbow into the hole cut with one of the nuts on the outside and the other put in place once the elbow was positioned. With the gas cap flange removed reach inside to hold the nut secure while tightening the elbow. (also use pipe dope intended for gasoline around all threads to prevent leaks)
Second while you have the cap flange off, you will want to use it as a pattern to cut a new flange. We used the 3/16" flat stock we had left over from the skid plate, but you could use 1/8" very easily or even an aluminum stock if weight is a conern.
In this new flange you are going to cut, use the stock fuel pump, inlet/outlet flange as a pattern for your inside cut of the new flange. mark the outside edge of the fuel pump flange, and the mark a second edge 1/4" inside the original line for the pump flange. This second line is where you will cut, giving you an edge to anchor the pump flange to the new outter flange that will attach to the fuel cell.
The new flange will be drilled to match the bolt pattern of the fuel cell while you wll use self tapping screws to attach fuel pump plate.
cut one more additiona hole for the vent return line and you are done cutting up your brand new purity fuel cell. (the vent return is in the upper corner of the following photo.
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010488.jpg
A major note must be made at this point! Typical RTV or any other silicone will not work with gasoline. I found a product called Tacky gasket that works great! (I'll have to get the complete name later and edit)
But this "sealient" is not enough to prevent leaks. What I used was rubber pond liner, again found at the local hardware store along with rubberized paper gasket material. using the gas cap flange again as a pattern I cut these materials and placed the Tacky gasket on all surfaces to create an air tight seal. (too much air into the tank and you will throw a check engine light)
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010489.jpg
the yellow snot looking stuff is the tacky gasket sealiant…you want to be liberal with your use of it.
For the fuel "delivery" I used a 1" stainless steel wrapped fuel line hose from Russell. Ideally 2" would be better suited as the 1" does not allow me to fill up at the gas pumps as I used to. The pump will "overrun" the 1" hose causing the pump to click off. I merely have to slow the rate down manually to fill the tank.
The RCI sprint car plastic fuel cell was selected because it fit perfectly between the frame rails of the tacoma, maybe a little too perfect for someone with leaf springs. With my springs the shackle bolts needed to be "trimmed"
Another note regarding using the stock fuel pump and this particular RCI fuel cell. The stock tank is 14" deep. the RCI cell is only 10.5" deep. So if you want use the stock fuel pump bracket, it must be shortened. I would go into detail, but my friend that helped with the project wants to take these brackets into production and offer them as a product
Let me know if there are any questions regarding this mod. I have been running my truck for one month since doing the relocation and I am actually really liking the difference. It makes the truck a bit more stable on the road giving more power to the rear axle due to the weight out behond the rear axle.
Once I replace my front axle shaft, I'll take the truck out to the trails (at this rate it won't be until snow wheel'n season)
Here are some additional photos not used for illustrations above:
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010491.jpg
shot from infront of rear axle viewing aft of the vehicle from the drivers side
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010486.jpgshot from passenger side looking back toward rear of truck. notice the tight clearence between the tank and the shackle?
One final note: an access hole was cut into the bed of the truck. We had issues with the fuel pump (that have been resolved) after I filled the tank up. so instead of unbolting the full tank to lower it to work on. I decided to cut a hole in the bed. Later I will be replacing the metal cut from the hole to make a "trap door" using hinges and dzues clips.
so do I need to let the mods know where to send my decal?:smokin:
Although this seems as a straight forward modification, there possibly was some "new ground " broken with this project.
First order of business was to decide on an alternate location. It is easy just to throw a fuel cell into the bed and be done with it, but that is too easy! besides my bed is already getting cramped with a full size spare 37" tire, 20 lb Co2 bottle and an ammo box, not to mention my trail trunk that gets anchored to the bed when I go out.
the original goal was to locate the 22 gallon fuel cell over the rear axle. This would provide added traction by placing weight directly over the axle. Problem being is the plans for the 4 link calls for a panhard/trac bar which would directly intersect with fuel cell. Putting the cell further forward was not an option due to the drive shaft.
So with fear of immitating a 1971 ford pinto, the decision was made to locate the fuel cell aft of the rear axle.
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010485.jpg
Once the decision was made, and measurements were taken three times. The frame was begun. Original idea was to make the hanging cradle from 1.5"x1.5" angle iron supported by .75" angle iron, with the front "legs" being supported from my existing shock bar.
What we ended up with (extra stock from a previous build) was 3"x3" angle iron for the cradle. Although this did make the cradle heavier, it did provide more security in regards to the "Pinto factor"
I won't go into detail on how to weld up the frame or supports as most here know the ins and outs of faberication.
I will comment on the skid plate design and application. Since putting the tank behind the rear axle, there is a potiencial of loosing some departure angle (especially on linked rigs such as what mine is intended to become) So with that consideration, I wanted to make a skid that would be able to take the abuse. So I opted for 3/16" plate I found in the drop metal section of my local metal supply (drop metal is cheaper due to it being the yards surplus). So after adding a center support to the cradle, on the outside of the frame using a 1/2"x 2" piece of stock (will explain shortly) I tacked the sheet to the bottom of the cradle.
The reason the support was added to the outside of the cradle frame was so that without having to drill holes into the sheet metal I created a natural valley and gap for drainage,also keeping the support under the plain of the fuel cell so that it remained even. this support being made out of 1/2"x2" also provides a location to locate a floor jack if needed while working on the vehicle, not to mention allows for greater protection to the rocks.
The last comment on the cradle is this. Still being concerned with the "pinto factor" I used more 1/2"x2" stock I had laying around for the back side cradle hangers/supports as well as some excess cut from the bottom skid plate. This extra was welded to the hangers as well as to the angle iron to create a verticle "skid plate" for the back side of the fuel cell. So if a compact car does rear end me, they are not going to get to the fuel cell (I still drive this truck daily) nor will backing into that 3 foot boulder puncture the cell either.
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010490.jpg
After adding a cross member across the rear part of the frame, the basic frame work was in place.
Many have already asked me what I did with the fuel pump situation, since tacos have an internal fuel pump. Did I convert to an exterior pump mounted to a frame rail or some other location on the truck?
The answer is no! We used the stock fuel pump and placed it back into the fuel cell along with all the other stock components placed into the new fuel cell.
We cut a hole into the front left corner of the fuel cell and ran a galvanized elbow obtained from the local hard ware store, along with two electrical conduit nuts the same size. Placed the elbow into the hole cut with one of the nuts on the outside and the other put in place once the elbow was positioned. With the gas cap flange removed reach inside to hold the nut secure while tightening the elbow. (also use pipe dope intended for gasoline around all threads to prevent leaks)
Second while you have the cap flange off, you will want to use it as a pattern to cut a new flange. We used the 3/16" flat stock we had left over from the skid plate, but you could use 1/8" very easily or even an aluminum stock if weight is a conern.
In this new flange you are going to cut, use the stock fuel pump, inlet/outlet flange as a pattern for your inside cut of the new flange. mark the outside edge of the fuel pump flange, and the mark a second edge 1/4" inside the original line for the pump flange. This second line is where you will cut, giving you an edge to anchor the pump flange to the new outter flange that will attach to the fuel cell.
The new flange will be drilled to match the bolt pattern of the fuel cell while you wll use self tapping screws to attach fuel pump plate.
cut one more additiona hole for the vent return line and you are done cutting up your brand new purity fuel cell. (the vent return is in the upper corner of the following photo.
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010488.jpg
A major note must be made at this point! Typical RTV or any other silicone will not work with gasoline. I found a product called Tacky gasket that works great! (I'll have to get the complete name later and edit)
But this "sealient" is not enough to prevent leaks. What I used was rubber pond liner, again found at the local hardware store along with rubberized paper gasket material. using the gas cap flange again as a pattern I cut these materials and placed the Tacky gasket on all surfaces to create an air tight seal. (too much air into the tank and you will throw a check engine light)
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010489.jpg
the yellow snot looking stuff is the tacky gasket sealiant…you want to be liberal with your use of it.
For the fuel "delivery" I used a 1" stainless steel wrapped fuel line hose from Russell. Ideally 2" would be better suited as the 1" does not allow me to fill up at the gas pumps as I used to. The pump will "overrun" the 1" hose causing the pump to click off. I merely have to slow the rate down manually to fill the tank.
The RCI sprint car plastic fuel cell was selected because it fit perfectly between the frame rails of the tacoma, maybe a little too perfect for someone with leaf springs. With my springs the shackle bolts needed to be "trimmed"
Another note regarding using the stock fuel pump and this particular RCI fuel cell. The stock tank is 14" deep. the RCI cell is only 10.5" deep. So if you want use the stock fuel pump bracket, it must be shortened. I would go into detail, but my friend that helped with the project wants to take these brackets into production and offer them as a product
Let me know if there are any questions regarding this mod. I have been running my truck for one month since doing the relocation and I am actually really liking the difference. It makes the truck a bit more stable on the road giving more power to the rear axle due to the weight out behond the rear axle.
Once I replace my front axle shaft, I'll take the truck out to the trails (at this rate it won't be until snow wheel'n season)
Here are some additional photos not used for illustrations above:
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010491.jpg
shot from infront of rear axle viewing aft of the vehicle from the drivers side
http://i208.photobucket.com/albums/bb211/Bear4x4/truck%20modifactions/P1010486.jpgshot from passenger side looking back toward rear of truck. notice the tight clearence between the tank and the shackle?
One final note: an access hole was cut into the bed of the truck. We had issues with the fuel pump (that have been resolved) after I filled the tank up. so instead of unbolting the full tank to lower it to work on. I decided to cut a hole in the bed. Later I will be replacing the metal cut from the hole to make a "trap door" using hinges and dzues clips.
so do I need to let the mods know where to send my decal?:smokin: