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Discussion Starter · #1 ·
Is it possible to replace the fuel sending unit without dropping the tank? If so how hard is it. Anyone ever done this and know how long it takes to drop the tank? I ftopped her off at the gas station the other day and fuel started pouring out the top.
 

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If you cut a hole in your cargo area to reach through to the top of the tank. However if your leaking fuel the sparks from ANY cutter could set that thing off and you'd be cancelling Christmas, if you know what I mean? I'm not to sure that I under stand just what your getting at, in your post, unless that you think the gasket on the sender/pick-up to the tank has gone bad? It may be a hose has some dry rot or a crack. Or the forward vapor canister return gromet for that hose fitting going back into the tank is leaking because it was just over filled when you topped it off last. Or the tank it self has a leak? I have changed the sending unit/pick-up on my 86 twice. It is a PITA. Big thing get your tank drained as close to bone dry as you can, drop in a well ventelated area away from the garage/houses and don't allow things that make sparks when your getting inside the tank. When did the leaking start and was it forward, left on the filler side aft, or to the center or the right? Or the back side? Can you even tell? Or has it stopped leaking and your driving it again?

It has usually taken me about 2 hours to drop, tend to what ever and re-install my tank. But in the 2 sender/pick-up's that I've changed, my tank has been down at least 10 times, trying to get the new sender calibrated the best way it can. Lets just say that I've got good at doing that part. That in it self is a whole other topic. I personally beleive that the new replacement sender/pick-ups are not manufactured correctly from Dodge any longer and will never work right what ever you do to calibrate them, its all BS. Poor engineering for a no longer supported year/model on behalf of Dodge. My tank is a 35 gallon, also.
 

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Discussion Starter · #3 ·
yeah I believe that the gasket on the sending unit has gone bad. but I'm not positive on that. What does in take to calibrate one of those things?
 

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Adam D said:
yeah I believe that the gasket on the sending unit has gone bad. but I'm not positive on that. What does in take to calibrate one of those things?
Good luck on calibration, I have a FSM (factory service manual) for my 86 RC and it does not have a single word of what is really going on to calibrate your 35 gallon sender/pick-up, other than making sure you have like 12 ohms when the pick-up is to the top and 78 ohms when at the bottom. (little tabs on the side of the resistor to help get right on with the ohms, this sets the E at the empty needle mark, and the F for the full fuel mark) All the rest (bending of the float arm for the proper reserve at tank empty "E" on the gauge) is by word of mouth, and who ever tells you how, its all kind of the same but some what different. My dealer ship told me, that you have to take a set of extension wires to the sender, with the tank on the ground and level. Then add 8 gallons of gas, now put the sender back in and out, bending the senders float wire just so, to get the gauge to point right on to the "E" of the gauge. This is all a bunch of crap, but because you have to do it with out breaking the float off of the wire, not bend a kink into the pick up tube at the same time. My first sender I broke of the float. (at $110.00) and the second was just as bad a PITA to calibrate.

This is for the 35 gallon tank, I don't know about the others! My tank reads true full up and the gauge goes down through "E" as well, but the stock sender had a hole lot more reasonable readings on the gauge ( accuracy) relative to the amount of milage verses actual fuel in the tank. No way you should have traveled 25 miles and be down to a 3/4 mark on the gauge from fill up. Then 60 mile on the od when the gauge reads 1/2 tank. Then 100 miles on the od when the gauge is 1/4 tank gas left, then at "E" its the od has 220 and then you can continue to drive to bone damn dry and put over 145 additional miles on the od before running flat out of gas at plus or minus 365 miles for the whole tank of gas. This is crap. The orignal was never that bad.

Well as in other posts, folks have recommended to have them re-manufactured. If I have to take this tank of mine down again, I'm going to send all the parts that I have left from the orignal and the first new one to a re-man joint and have that done. Good luck.
 

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to calibrate hook up the wire before installing the unit in the tank and ground it to the truck then bend the arm so that the float is slightly above the pickup turn on the ignition and check the reading on the gauge if necessary bend the arm until you get the gauge to read empty when the float is just bove the pick up i always leave a little extra clearance so i'm sure not to run out 8)
 

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to calibrate hook up the wire before installing the unit in the tank and ground it to the truck then bend the arm so that the float is slightly above the pickup turn on the ignition and check the reading on the gauge if necessary bend the arm until you get the gauge to read empty when the float is just bove the pick up i always leave a little extra clearance so i'm sure not to run out 8)
 

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there is a good chance it is not the sending unit leaking, there is a vent line that runs into the tank right next to the sending unit, this is held in with a rubber grommet, these grommets tend to split alot, this is more than likely what is leaking.

and unless you cut your floorboard, you have to drop the tank to fix.

eric
 

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Discussion Starter · #8 ·
Well I dropped the tank,took about an hour, the gasket for the sending unit was split. The arm on the sending unit had a little piece of like cassette tape tape ,only thinner, wrapped around it and the fuel pick up so I think that is why my guage was reading wrong and have decided not to pay the $120 for a new unit.

Yeah that valve is called a rollover valve. I know because I broke the nipple off trying to disconnect the hose. so when I went to the dealer they said I can't get the gasket for the sender w/o the sender, so now I have to make my own. and they nolonger can get that little rubber grommet for the rollover valve so I will be forced to use my old one on the new valve, It looks to be in pretty good shape so I hope I don't have a problem.
 

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Adam D said:
. they nolonger can get that little rubber grommet for the rollover valve so I will be forced to use my old one on the new valve, It looks to be in pretty good shape so I hope I don't have a problem.
yeah i discovered this when i first got my rc. my grommet was split in 2 and everytime i would fill up it would spray fuel everywhere, i ended up having to get a sealer plug and sealing it shut, however, now i can't fill my tank all of the way due to the air in the top of the tank having nowhere to go. i have 3 other tanks with the valve i need to drop my tank and replace that part, just havent gotten to it yet

eric
 

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Adam D said:
Well I dropped the tank,took about an hour, the gasket for the sending unit was split. The arm on the sending unit had a little piece of like cassette tape tape ,only thinner, wrapped around it and the fuel pick up so I think that is why my guage was reading wrong and have decided not to pay the $120 for a new unit.

Yeah that valve is called a rollover valve. I know because I broke the nipple off trying to disconnect the hose. so when I went to the dealer they said I can't get the gasket for the sender w/o the sender, so now I have to make my own. and they nolonger can get that little rubber grommet for the rollover valve so I will be forced to use my old one on the new valve, It looks to be in pretty good shape so I hope I don't have a problem.
Adam, this is on your 76 TD? Just curious...the gasket that split is it a cork gasket with 5 holes in it?
 
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