In cab gas tank stuff

[71CHEVYSHORTBED402]

Do the 71 & 72 trucks use the same in-cab gas tank?

I just pulled this tank off my 71 C-10. I'm thinking about installing it on my 72 C-20 driver, which has a bad sender anyway...............I read where the original gas caps differed 71 Vs 72. I don't know, I've got two after markets that fit both tanks. Perhaps the differences were cosmetic?

Other than that, a few captions and questions/comments in the images below. Thank you for any input.

[LongBox]

Can't answer all the questions, but I used carburetor cleaner to clean the filter "sock" on my sender unit, and my brass float had a crack and was filled with gas. I repaired it myself, by making the crack a bit larger, emptying the gas, cleaning the area around the crack with fine sandpaper, then soldering it up using an electric soldering iron. I used a large iron, 250 watts, in order to create enough heat to do the repair.

Six months later, still working just fine. The main filter, in my truck, is under the cab, where the pipe comes through the floor, right hand side. It's a 69.

[71CHEVYSHORTBED402]

No saving my filter sock. Thanks for the response though.

There's more than one way to dry a tank. The blower on my shop vac is one of my favorite tools.

[towbar]

The inside of your tank looks great to me.
I just replaced my 72 tank with an aftermarket tank which was supposed to be for a 72 with the emissions lines to the charcoal canister in the engine compartment. The neck on the new tank was much larger and my original 72 cap did not fit, it was terribly loose to the point it would fall off. No way the cap would have stayed on. I cut off my original 72 neck and tig'd it on to the new tank. I picked up a new sender with filter cheap, and replaced the brass float with a plastic one from a Jeep, fit perfectly, and should never leak and fill with fuel. I found the info on the Jeep float on here as well.

I think the tube from the neck to the tank it to aid fuel filling and allow air to evacuate the tank and not blow fuel like a whale port. May be wrong? if so, someone will correct my thinking hopefully.

[71CHEVYSHORTBED402]

Originally Posted by towbar

The inside of your tank looks great to me.
I just replaced my 72 tank with an aftermarket tank which was supposed to be for a 72 with the emissions lines to the charcoal canister in the engine compartment. The neck on the new tank was much larger and my original 72 cap did not fit, it was terribly loose to the point it would fall off. No way the cap would have stayed on. I cut off my original 72 neck and tig'd it on to the new tank. I picked up a new sender with filter cheap, and replaced the brass float with a plastic one from a Jeep, fit perfectly, and should never leak and fill with fuel. I found the info on the Jeep float on here as well.

I think the tube from the neck to the tank it to aid fuel filling and allow air to evacuate the tank and not blow fuel like a whale port. May be wrong? if so, someone will correct my thinking hopefully.

Where did you get your tank? Brass float? The buoy I called a ball in the pic.?

Tell you what, don't be in a hurry to dry these tanks. The blower has been running 45 minutes or so and it's still damp along the seams.

[71CHEVYSHORTBED402]

Wholly molly look at this tank. All I used was water. Have tempted to use it with the rebuild.

Something to be said for Nevada climate and a garage. I did not expect this though:

[towbar]

Got the tank and plastic float from Summit Racing....fit very well...no issues except the cap fitment. Tank part # SUM-255050......about 200 bucks
Float part # is OMX-1772901........only 4 bucks, originally from any 70's jeep CJ5 model....fit perfect
sending unit came from Brothers.....less than 30 bucks I think.

there was no cleaning or sealing mine...had sat for about 15+ years and was junk.

[towbar]

nice.....id use that tank any day! NV is a good place for survivor pieces that aren't rotted to bits

[71CHEVYSHORTBED402]

Originally Posted by towbar

Got the tank and plastic float from Summit Racing....fit very well...no issues except the cap fitment. Tank part # SUM-255050......about 200 bucks
Float part # is OMX-1772901........only 4 bucks, originally from any 70's jeep CJ5 model....fit perfect
sending unit came from Brothers.....less than 30 bucks I think.

there was no cleaning or sealing mine...had sat for about 15+ years and was junk.

I hear good things about Spectrum tanks. Edit: Spectra

Originally Posted by towbar

nice.....id use that tank any day! NV is a good place for survivor pieces that aren't rotted to bits

Hmmmmm............ It would save me three-four bills.

[FirstOwner69]

First- I'd buy a new sending unit. They are pretty cheap. There does seem to be 2 price points though. Some around $30. Some around $50.

Second- Replace the float with the Jeep float mentioned above.
http://www.ebay.com/itm/Fuel-Tank-Se...VUKs7L&vxp=mtr


Why? I bought the higher priced sending unit and the float leaked almost immediately. I replaced it with the Jeep float. It's not worth the hassle to risk having to pull the sending unit again.

[71CHEVYSHORTBED402]

Originally Posted by FirstOwner69

First- I'd buy a new sending unit. They are pretty cheap. There does seem to be 2 price points though.

Second- Replace the float with the Jeep float mentioned above.
http://www.ebay.com/itm/Fuel-Tank-Se...VUKs7L&vxp=mtr


Why? I bought the higher priced sending unit and the float leaked almost immediately. I replaced it with the Jeep float. It's not worth the hassle to risk having to pull the sending unit again.

Thanks FirstOwner. Any ideas for a filter? Thoughts on reusing the original tank on the project? I only want to do this once. Whichever truck I use it on the tank gets another wash. I didn't spend a lot of time on it. The primary intent was to remove all the fumes.

[FirstOwner69]

Your tanks both look great.

I don't think anyone sells the filters. It seems to me there was a thread about that couple years, but I don't recall the conclusion.

[71CHEVYSHORTBED402]

Originally Posted by FirstOwner69

Your tanks both look great.

I don't think anyone sells the filters. It seems to me there was a thread about that couple years, but I don't recall the conclusion.

Ha, sorry, it's the same tank. Second pic is after water. This came out of the 71. I figure to throw it back in with the rebuild or install it on the 72.

On a rare occasion I have smelled gas. Perhaps after topping off the tank. If I remember right, that's more likely from the gas cap? I didn't see any leaks, obviously, and the hoses looked good.

[FirstOwner69]

So... what do I know? Check these out. I think you'll need the 3/8" version.
http://www.ebay.com/itm/for-GM-model...1X~l4t&vxp=mtr

http://www.ebay.com/itm/for-GM-model...pX~pBd&vxp=mtr

Smelling gas is not unusual when the tan is full.

[71CHEVYSHORTBED402]

Originally Posted by FirstOwner69

So... what do I know? Check these out. I think you'll need the 3/8" version.
http://www.ebay.com/itm/for-GM-model...1X~l4t&vxp=mtr

http://www.ebay.com/itm/for-GM-model...pX~pBd&vxp=mtr

Smelling gas is not unusual when the tan is full.

Thanks again Mr. J. You are correct, 3/8" line. I wonder if those filters go on like "Chinese handcuffs". Edit: Okay, maybe not Chinese handcuffs..........HA!...........Looks like they just twist on until they can't go anymore. I pulled the old one off.

[FirstOwner69]

Friction fit.

[FirstOwner69]

Hmm... Looks like Tamraz's is out of the 3/8" size. Probably temporarily. Just search eBay Motors for "GM sending unit filter" to see others. You'll even see some genuine GM filters.

[71CHEVYSHORTBED402]

Originally Posted by FirstOwner69

Friction fit.

I actually looked that up..........Yep, "friction fit". That makes for 20ish things I learned today.

Originally Posted by FirstOwner69

Hmm... Looks like Tamraz's is out of the 3/8" size. Probably temporarily. Just search eBay Motors for "GM sending unit filter" to see others. You'll even see some genuine GM filters.

I'll be checking, thank you.

[71CHEVYSHORTBED402]

Foam rubber:

[71CHEVYSHORTBED402]

Appreciate all the help. Perhaps paying it forward with lots of notes. Feel free to correct etc.............Thanks for the help

Fuel Tank & Fuel Sender NOTE: Install the filler hose line before installing the tank. See below.

Fuel tank pads: The fuel tank uses three 1/8" thick pads that glue onto the floor, wall, and where the floor pads meet. The floor pad is 1.1/2" x 4', which are two 32" strips. The RH strip lays on top of the LH strip along center. These fit along the top front edge where the tank sits. The wall pad is 5.3/4" x 30".

Fuel tank installation: The fuel tank mounts to the cab using seven 1/2" head tapered screws with integrated tooth washers, and washer plates. The screw threads are 5/16-18 x 1.1/8. The lip on each washer plate faces front. The fuel neck uses a gasket that inserts from outside the truck.

Fuel sender:
• A filter sock is friction fitted onto the bottom hard line of the sender. The sender uses a float ("buoy") to measure the fuel level.

• The sender uses an O-ring where it attaches to the tank. The O-ring has a tab on the interior. Couldn't tell you where this is placed, but there is some clearance on the base of the sender.

• The fitting on the sender is the RH portion of the sender. Secure the sender to the fuel tank using a lock ring. This ring installs by striking each of four tabs on the ring (clockwise for installation). Insert the ring underneath the fuel tank ring, and strike evenly to maintain center.

NOTES:
It's been recommended to replace the fuel sender float with a Jeep OMX-1772901 (a.k.a. 17729.01), because they last longer.

Replace the float, filter sock and lock ring when re-installing a sender.

Fuel sender wire: An 18 AWG tan wire routes from FUAL GA. on the fuse box down the LH floor gutter to the pin on the fuel sender. This wire is retained using the J-clip on the dimmer switch, the bottom retainer behind the door jam, and two rubber coated clips placed onto the top edge of the fuel tank. NOTE: The retainers on the tank are the same clips used for the RH door jam wire.

Fuel & EEC Vent Lines Fuel & vent lines:

Fuel: The line to the fuel pump is 3/8" ID. (Routing: Fuel sender line to hard line using a 5/8" nut > through rear hole in the cab floor > rubber hose with pinch clamps > hard line along the RH frame > rubber hose to the fuel pump inlet using pinch clamps).

Vent:
• The line for fuel tank ventilation is 5/16" ID. (Routing: Rubber hose from top RH corner of fuel tank to top port of vent pipe assembly > rubber hose on the bottom port of the vent pipe assembly to the hard line down the side of the tank, across the floor and through the front hole in the cab floor > rubber hose with pinch clamps > hard line along the RH frame > rubber hose to the vapor canister using pinch clamps).

• Vent pipe assembly: The vent pipe assembly inserts into the upper RH pocket of the cab. The assembly uses a retainer that mounts to the back of the sheet metal below the pocket. The retainer portion faces rear. The retainer is secured using a 1/2" flathead bolt, and a K-lock nut. The bolt thread is 5/16-18 x 5/8. The bolt inserts from the rear. NOTES: The vent pipe assembly won't drop but an inch because it should "hang " near the top of the pocket. Push the assembly up and the bottom toward the corner for removal. The pipe assembly was installed when painted from factory.

• Vent line - retainers: The vent hard line attaches to the tank using three retainers. Two retainers mount on top of the washer plates using the bottom two screws for mounting the fuel tank. The retainer portion faces down and front The third clips onto the edge of the fuel tank, with the retainer portion facing front. This retainer was placed approx. 7" from the bottom of the bend in the hard line.

Filler line: A 3/8" ID rubber hose runs from the filler neck to the top LH corner of the fuel tank. This hose was 3.3/4" long. This hose attaches using two 5/16" head screw clamps.

NOTES:
The holes in the floor use split grommets.

The upper hose for the vent pipe assembly was 11.1/2" long and is stamped "EVAP" in places. The lower hose for the vent pipe assembly was 5.3/4" long.

The rubber hoses for the vent line inside the cab use four slot head screw clamps.

The vent line on the floor must clear belt buckle placement.

Foam rubber was inserted into the upper pocket along where the vent pipe assembly was installed. Course there wasn't much left of it. I suspect foam rubber was used in both upper cab pockets.

The vent line was run as outlet from the rear fuel port on the fuel pump to the fuel tank, because the vapor canister had been removed.

Apparently an EEC system requires a un-vented gas cap to work properly, while without EEC would require a vented cap. Word is some caps vent one direction for allowing air in, which is unconfirmed. I've also read "all caps have some type of ventilation", also unconfirmed.

See http://67-72chevytrucks.com/vboard/a...1&d=1368198856

Vapor Canister (a.k.a. Charcoal Canister) The vapor canister bracket mounts using the same screws that mount the RH fender to the gusset.

The belt mounts the canister to the bracket using two 7/16" head tapered screws with integrated washers. The screw threads are 1/4-20 x 1/2. Correct positioning of the canister is the valve ports face the rear.

See: https://www.youtube.com/watch?v=8HmiBp9ibfU

[71CHEVYSHORTBED402]

Here's a picture I was asked for. It's a fiber of some sort. From here I'd think rubber is a good option, you can buy whatever length and thickness and cut as required.


For what it's worth post 20 is probably a decent guide, but no doubt needs to be revised/simplified as I rebuild her