Kenosha Warrior Posted September 11, 2008 Share Posted September 11, 2008 Never done an MJ fuel pump before, any hints tips tricks? Will have to do one on the new truck. Link to comment Share on other sites More sharing options...
comanche87 Posted September 11, 2008 Share Posted September 11, 2008 hey.it's not that hardif it's down to a 1/4 or 1/8. Its best to have the truck on a lift or the pass side jacked up. There's a harness and 2 lines you have to disconnect. There is a metal ring you have to turn off. Then the whole assembly can slide out.be careful that a plastic tab towards the bottom doesn't snap.you may have to trim the new one a lil to get it to fit In. Then same as reversed in removal. If any ?s hit me up.hope that helps. Link to comment Share on other sites More sharing options...
johnnyc Posted September 12, 2008 Share Posted September 12, 2008 I just went through this on mine. I tried to do it without dropping the tank. But that only resulted in a major leak due to the o-ring and locknut not seating properly. Did it again, this time dropping the tank. It was much, much easier doing it this way. You can see into the tank to make sure that everything is in the proper position. And it's a lot easier to get the lockring on too. I would suggest getting the proper o-ring from the dealer. The aftermarket ones I've seen are squared, as opposed to being round. Link to comment Share on other sites More sharing options...
Kenosha Warrior Posted September 12, 2008 Author Share Posted September 12, 2008 Ah, thanks for the tips. I'm going to attempt it with the tank in the truck still, Ill have an extra set of hands to keep stuff steady. If that fails, then Ill drop the tank, Link to comment Share on other sites More sharing options...
ComancheKid45 Posted September 12, 2008 Share Posted September 12, 2008 I did mine this past Spring in the truck....it seeped alittle bit after reinstalltion but after a week or 2 the O ring seemed to seat itself and i have no more leaks 8) Link to comment Share on other sites More sharing options...
mjeff87 Posted September 12, 2008 Share Posted September 12, 2008 you can do it without dropping the tank. I've done it twice so far on mine and will be doing it again shortly to swap a 4.0 pump in place of the current 2.5 pump (swapping engines at the moment). Pull the driveshaft so you have more room to work (not essential, but it does help especially when reinstalling). The OEM assembly is prone to cracking the hard lines where they enter the pump assembly, so rather than pulling the two soft lines off at the tank, I opt to disconnect them underneath the bed where the soft lines reconnect to the hard lines. That way, you don't unnecessarily stress the fittings that come out of the assembly and risk the chance of them cracking. The bottom of the assembly has a small conical rubber grommet that seats itself inside a cup in the inner tank, which may not stay attached when you pull the assembly. If it stays in the cup when you pull it, you'll have fun getting the tube realigned with it when you put it back in. Take your time and don't try to force things....eventually you will find the "sweet spot" and everything will line up properly. Last time around I had to use the squared off O-ring that jonnyc mentioned. It took a little effort, but I did get it to seal. You have to make sure it's centered when you tighten the lockring back up. It's a bit of a PITA, but it does work if you take your time with it. I agree that the OEM rounded O-ring is alot easier to work with. Jeff Link to comment Share on other sites More sharing options...
johnnyc Posted September 12, 2008 Share Posted September 12, 2008 The bottom of the assembly has a small conical rubber grommet that seats itself inside a cup in the inner tank, which may not stay attached when you pull the assembly. If it stays in the cup when you pull it, you'll have fun getting the tube realigned with it when you put it back in. Take your time and don't try to force things....eventually you will find the "sweet spot" and everything will line up properly. That's another good reason for dropping the tank. If you don't know what it looks like, it's kinda hard to to get that tube into the hole. The first time I did it, I just guessed that I got it in. :D When we dropped the tank, I saw that the rubber conical grommet had fallen off and was laying in the bottom of the tank. It would have been impossible to retrieve the grommet had we not dropped the tank. Link to comment Share on other sites More sharing options...
tallon2064 Posted September 12, 2008 Share Posted September 12, 2008 I have to agree that dropping the tank is the way to go. I have done it both ways on mine and regretted not dropping the tank the first time. Just an FYI if you buy the whole assembly from AUTO ZONE IT DOES NOT FIT THE 23 GALLON TANK ON THE LONG WHEEL BASE MODEL MJ, ALTHOUGH THEY SAY IT DOES!! Link to comment Share on other sites More sharing options...
fiatslug87 Posted September 13, 2008 Share Posted September 13, 2008 Maybe a helpful hint. To remove the locking ring I used a brass rod (don't want sparks) as a punch and tapped it with a hammer. Link to comment Share on other sites More sharing options...
Kenosha Warrior Posted September 24, 2008 Author Share Posted September 24, 2008 Got'er last Friday. As per your experiences, the conical grommet stayed firmly planted in the tank, got the pump'n'stuff out and swapped, props to Jeff for the tip on the rubber line disco spots. Final report? SHE RUNS! First AW-4 Jeep and hoooboy, its a nice'un Link to comment Share on other sites More sharing options...
mjeff87 Posted September 24, 2008 Share Posted September 24, 2008 :cheers: Link to comment Share on other sites More sharing options...
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