Fuel pump assembly

[ftpiercecracker1]

One of the nipples coming out of the fuel tank has cracked all the way around its base and has started to leak quite a bit. I tried to remedy the problem with a healthy slathering of JB weld, which has held up admirably, but its obvious JB and gas don't get along.

 

I need to know if i can get an ordinary Cherokee fuel pump assembly to replace mine. Any problems with the wiring or fitment?

 

The tank is an aftermarket Spectra brand 18 gallon unit i bought off RockAuto a few years back.

 

Thanks,

FPC.

[Pete M]

pretty sure I remember reading that the cherokee assembly is different. :(

[AeroNautical]

I was told it was an exact mirror of what was in the MJ. The pump works, but the entire assembly is different. 

[Pete M]

search the site for dakota and gas.  I can't remember if it's the pump assembly that works or the entire tank, but something swaps in and can be easily purchased.

[buckwheat]

I used the cherokee sending unit/ pump assembly recently. You have to get a gas tank without the baffling inside. Like PFCLeist stated the MJ and XJ units are mirror images. With the new tank, it has worked wonderfully. Also I am curious what why you say JB Weld and gas don't get along. Directly from their website: 

Is J-B Weld resistant to water and/or gasoline?

When fully cured, J-B Weld is completely resistant to water, gasoline, and about every other petroleum product or automotive chemical. For wet-surface or submerged water or gasoline repairs, try our SteelStikor WaterWeld.

 

If you want I have my old sending unit and pump (pump is going bad) that I would be willing to sell to you. PM me you're interested.

[ftpiercecracker1]

 

I used the cherokee sending unit/ pump assembly recently. You have to get a gas tank without the baffling inside. Like PFCLeist stated the MJ and XJ units are mirror images. With the new tank, it has worked wonderfully. Also I am curious what why you say JB Weld and gas don't get along. Directly from their website: 

Is J-B Weld resistant to water and/or gasoline?

When fully cured, J-B Weld is completely resistant to water, gasoline, and about every other petroleum product or automotive chemical. For wet-surface or submerged water or gasoline repairs, try our SteelStikor WaterWeld.

 

If you want I have my old sending unit and pump (pump is going bad) that I would be willing to sell to you. PM me you're interested.

 

 

 

Interesting.  The JB weld hasnt dissolved or anything like that, its just soft. Like it never fully cured. I can still twist the nipple ( :brows:) the same amount as i could before applying the JB.  I figured that since i am still leaking fuel in the general area it had to be the JB weld, but maybe not. Either way I am still leaking fuel. Its the factory assembly and very rusty so the nipple breaking was just the tipping point i needed to justify replacing it.

 

Thanks for the offer buckwheat, i will consider it.

 

 

 

 

As far as the XJ assembly goes, will it not work because of the baffle in the tank? I put in a new spectra tank a year or so ago, but it has the baffle in the bottom.

 

 

Why does it matter that its the mirror image of the MJ assembly? What's the deal?

 

I dug this photo up comparing the two side by side.

 

 

[buckwheat]

I accidentally ordered the Spectra tank with the baffle the first time. I tried to fit the XJ sending unit and pump assembly into it and both the fuel strainer and the sending unit arm were hitting on the baffle. Since the strainers and sending arms are 180 from each other one fits nicely inside the baffling, and the other doesn't. I am sure you could change a few things and use the XJ hardware. But I decided to go the stupid route and make a tank that fit the XJ assembly. Kinda up to you. I think if you google "site:comancheclub.com xj sending unit in MJ" you will find a few good articles of people who have put the XJ pieces in an MJ. That's what I based my work off of.

[ftpiercecracker1]

Sooooo does that mean they make an mj/xj tank without the baffle? If so, that would be the permanent solution.

[buckwheat]

Indeed they do. I believe it is the JP5A. It was sold for the Renault diesel engines. Should not have a baffle inside, but fits exactly the same as the original tank. I also went a further step and put a sump/ baffle into the tank after I bought it. This way I don't have to worry about gas pooling away from the pick-up tube when the tank gets low. Definitely something you might want to think about.

 

I know some other people on here have made the XJ assembly work in the MJ tank. Maybe one of them could chime in? Otherwise I have been running with mine for ~500 miles and no problems. 

[ftpiercecracker1]

Indeed they do. I believe it is the JP5A. It was sold for the Renault diesel engines. Should not have a baffle inside, but fits exactly the same as the original tank. I also went a further step and put a sump/ baffle into the tank after I bought it. This way I don't have to worry about gas pooling away from the pick-up tube when the tank gets low. Definitely something you might want to think about.

 

I know some other people on here have made the XJ assembly work in the MJ tank. Maybe one of them could chime in? Otherwise I have been running with mine for ~500 miles and no problems. 

 

 

How in the heck did you add a baffle? If it requires cutting the tank open i might as well stick with the tank i have and cut into it to remove/move my baffle. 

 

I did not understand what you were talking about at the end of your post. What have you been running for 500 miles with no problems?

[buckwheat]

Sorry for the confusion. I bought the MJ tank without the baffle, then cut an opening in the bottom of it, made an open topped box that would fit inside the hole (without interfering with the XJ pump assembly), and welded that in place. This way I have a tank that fits like original, a baffle that works with the XJ equipment, and because I built the box taller than I needed I also have a sump for the fuel pick-up. This is the set-up I have been running without issue for a while.

 

I hope this makes things clearer. And you might want to stick with your tank, thats entirely up to you. I was trying to answer your questions about how to make the XJ assembly work and maybe give you a few ideas on improvements as well. Sorry if this didn't come across well. Good luck on getting your problem fixed.

[Jeep Driver]

Sorry for the confusion. I bought the MJ tank without the baffle, then cut an opening in the bottom of it, made an open topped box that would fit inside the hole (without interfering with the XJ pump assembly), and welded that in place. This way I have a tank that fits like original, a baffle that works with the XJ equipment, and because I built the box taller than I needed I also have a sump for the fuel pick-up. This is the set-up I have been running without issue for a while.

 

I hope this makes things clearer. And you might want to stick with your tank, thats entirely up to you. I was trying to answer your questions about how to make the XJ assembly work and maybe give you a few ideas on improvements as well. Sorry if this didn't come across well. Good luck on getting your problem fixed.

Are you a welder by trade?

 

How did you weld it?

 

Did you leak test it? if so, how so?

[ftpiercecracker1]

Thanks man that helps a lot. :thumbsup:  Ya, i was totally lost there for a bit, but i now understand completely.

 

I definitely have a couple of options to consider.

 

1. modify my current tank

 

2. buy new tank without baffle

 

3. Pray i find a decent MJ assembly in a junkyard

 

 

I also thought about buying a plastic dakota tank.

 

 

No matter which option i go with i am also going to use this opportunity to try and setup a working fuel gauge.

 

 

 

Thanks for everything buckwheat.