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Old 03-30-2021, 02:23 PM   #1
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Lift pump replacement question ISL 400

Those of you that have replaced the pump, have you replaced the pump, manifold and bracket or just the lower pump and gasket with the 3 bolts?

If I can just replace the pump, gasket, it looks like it would be an easier job.

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Old 03-30-2021, 07:22 PM   #2
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I replaced the whole thing because that was what I could get but I don't think there would be a problem to replace just the pump
still working 2002 monaco windsor
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Old 03-30-2021, 08:06 PM   #3
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To replace my entire lift pump the starter had to be removed to access the bolts holding the pump to the block.
2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG 11B5MX,Infantry retired;Good Sam Life member,FMCA." My fellow Americans, ask not what your country can do for you, ask what you can do for your country. John F. Kennedy
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Old 04-01-2021, 11:38 AM   #4
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parts list for the ISL Lift pump

Here is the Parts list for the Lift pump from Cummins Parts.
Attached Files
File Type: pdf Lift Pump 2021-03-31-163404.pdf (361.9 KB, 57 views)
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Old 04-01-2021, 07:05 PM   #5
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Have you been able to purchase just the pump itself. I did a quick search with no luck.

There are gaskets available on Ebay for ~$15, two different types depending on SN.
Jim J
2002 Monaco Windsor 38 PKD Cummins ISC 350 8.3L
2005 Jeep Grand Cherokee w/5.7 Hemi
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Old 04-02-2021, 03:16 PM   #6
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I bought the pump complete from Cummins. I thought about trying the gasket route, but needed it for a trip this week and couldnít gamble on the gasket being the issue.
Iím glad I did as I believe the pump was leaking from the electrical connection. The pump sits above the starter inside the frame rail, so itís almost impossible to see it from below.
Going through the bedroom access above was relatively easy to remove the pump. When replacing it make sure to connect the power at the bottom of the pump before dropping it into position.
Itís held on by 3 bolts to the block.
The new pump had 2 extra ports that the OEM didnít have so make sure to order the right size plugs when you get the pump.
It was easy to reach the fuel filter while I was in the bedroom. It had one more fuel fitting and 2 bolts to remove the whole assembly and take it to the bench to remove and replace the filter.
I cycled the lift pump 3 times, then started. It stopped after a bit so I cycled the lift pump again and started with no further issues.

Big thanks to Dewey219 for his advice!

Willie Nelson.. On the road again!
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Old 04-03-2021, 10:28 PM   #7
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If it were mine I’d use the money to install a fass pump rather then another lift pump you would be surprised how much better the motor will perform.
2002 country coach allure 32 foot dual slide 350 cummins ISC
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Old 04-04-2021, 11:54 AM   #8
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I replaced my lift pump it was a pain then a few years later I installed a fass pump and left the lift pump in place just rerouted the fuel lines around it was much easier then replacing lift pump
still working 2002 monaco windsor
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ace, pump, replace, replacement

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