MJ fuel sender problem

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Phils67
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MJ fuel sender problem

Postby Phils67 » Sat Nov 10, 2018 5:02 pm

Just picked up a 90 MJ 2.5 4spd 2wd SB. 2 days after I bought the truck the fuel pump went bad. Replaced the pump and the sender started leaking from the supply side. Repaired it with JB WaterWeld. Claims it is ok for gas and oil. Drove it all day with no leaks but my OCD is going nuts knowing it is repaired like that. I can not source a new sending unit at any of the local parts houses (advance, autozone, or napa). Can not find it on rockauto or quadratec either. Does anyone know where i can find one? Or is it 100% obsolete and I am going to become the guy that buys every one i can find in the boneyards and reconditions them all strictly for hoarding purposes? I'd really just like to find a source for replacements though if anyone can point me in the right direction.
1967 Gladiator J2000/ 4.0MPI/T18/Twin sticked D20/ locked 44/welded 53/4.27s/4" Hell Creek,35s, pending J20 axles with Detroits and 3.73s/ pending lift kit downsizing and late model spring-under-frame front

1990 Comanche/ 2.5TBI Renix/AX4/2wd SporTruck base model shortbed/97+ front clip and door conversion/daily driver

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Stuka
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Re: MJ fuel sender problem

Postby Stuka » Sat Nov 10, 2018 6:12 pm

Wow, I would expect it to be the same as the XJs, but it must not be.

As for the JB weld, it is fine to use like you did. It may last years, or a week. Depends on how much vibration it gets.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Lifted and stuff
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

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Phils67
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Re: MJ fuel sender problem

Postby Phils67 » Sat Nov 10, 2018 6:23 pm

Its got the smaller tank with a side mounted sending unit. Super easy to change without lowering the tank. Apparently this sender is specific to this tank in the 87-90 model year range (thanks Renault!). I can not locate a new one for the life of me. I used a 1/4 of a tube of the putty to cover a pinhole. Hopefully it holds up until I locate a new sender. The pump, tank, lockring, lines and filter are now all new and rust free. The sending unit is pretty crusty though. The thought of JB weld being the only thing preventing pressurized fuel from spraying on a hot exhaust has my gut feeling like someone punched me.
1967 Gladiator J2000/ 4.0MPI/T18/Twin sticked D20/ locked 44/welded 53/4.27s/4" Hell Creek,35s, pending J20 axles with Detroits and 3.73s/ pending lift kit downsizing and late model spring-under-frame front

1990 Comanche/ 2.5TBI Renix/AX4/2wd SporTruck base model shortbed/97+ front clip and door conversion/daily driver

MJMadness
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Joined: Wed Aug 06, 2014 1:46 pm

Re: MJ fuel sender problem

Postby MJMadness » Wed Nov 14, 2018 12:18 pm

Don't blame Renault for that sending unit being unique. It's Chrysler that changed it, and ruined everything.

You can find them NOS or good used on eBay from time to time. Or go put a wanted ad up on www.ComancheClub.com.

Another option would have been to weld, silver solder, or braze it. I've seen more than a few successfully repaired with brazing, and I would trust that repair indefinitely.

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Phils67
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Re: MJ fuel sender problem

Postby Phils67 » Wed Nov 14, 2018 4:01 pm

If this fails that is my plan. Remove it, weld it, test the tube with compressed air, and reinstall. Hopefully it holds up for a while though. So far so good
1967 Gladiator J2000/ 4.0MPI/T18/Twin sticked D20/ locked 44/welded 53/4.27s/4" Hell Creek,35s, pending J20 axles with Detroits and 3.73s/ pending lift kit downsizing and late model spring-under-frame front

1990 Comanche/ 2.5TBI Renix/AX4/2wd SporTruck base model shortbed/97+ front clip and door conversion/daily driver

letank
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Re: MJ fuel sender problem

Postby letank » Wed Nov 21, 2018 4:04 pm

Phils67 wrote:Repaired it with JB WaterWeld. Claims it is ok for gas and oil.


I repaired the metal tank on the 74 with JB weld, it was a trail repair, one of the strap broke and the tank rubbed on the frame... after an hour the smell of gas made its way to the cab... lifted the wheel on a rock, cleaned, degreased, let it dry for a few hours, then plastered JB weld, let it dry for 24hrs... it was good for over 8 years, until another ding on the tank forced a removal and the proper repair.

For pin holes, you can use a specific product, that you lather on a sheet metal screw and tap it in... the gas is the catalyst... works well too... very useful in the desert when the nearest gas is hours away.
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (226 Kmiles... the running test lab)
See Engine bits and Fuel and brake lines, and Body work

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Phils67
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Re: MJ fuel sender problem

Postby Phils67 » Wed Nov 21, 2018 4:56 pm

I have attempted to repair this multiple times. In the 3 weeks I have owned it i have driven it 5 days. The sender has been in and out 12 times now during that time period. It leaks worse every time I try to repair it. It is in worse shape than I thought. Nothing seems to be working. It really needs to just be replaced.
1967 Gladiator J2000/ 4.0MPI/T18/Twin sticked D20/ locked 44/welded 53/4.27s/4" Hell Creek,35s, pending J20 axles with Detroits and 3.73s/ pending lift kit downsizing and late model spring-under-frame front

1990 Comanche/ 2.5TBI Renix/AX4/2wd SporTruck base model shortbed/97+ front clip and door conversion/daily driver


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