Cat loader reprime

Mission Creek · Apr 7, 2017

Changed fuel filters and separator filter on a Cat 938G but can't get to reprime correctly. What's the standard procedure on these Caterpillars. Thanks,

- Jeff

dpendzic · Apr 8, 2017

easiest way is to pressurize the fuel tank to about 5 psi and then bleed progressively down stream on the fuel line/system all the way to the injectors getting the air out of the system

warbaby · Apr 8, 2017

Cut a section of inner tube with the valve core on it to fit over the fuel tank filler neck. Secure it with a big hose clamp, pressurize it with some air and either open up your bleed screws, or just crank it until it starts. Just don't overheat that starter!
Good luck

AJ. · Apr 8, 2017

Cat 938G with a 3126 engine has the common rail fuel system as I remember, any filter or separator that is mounted vertical fill it with clean fuel to the brim before fitting,loosen the primer on top of the separator,open the bleeder on the transfer pump and operate the priming pump till air free fuel comes from the bleeder close it,keep on operating the primer till it goes solid,start the engine on low idle,if its coughing and spluttering leave run it till it clears.
AJ

Mission Creek · Apr 8, 2017

This model has the separator with primer and then two fuel
filters mounted opposite vertically (both facing into each other
one on top and bottom). In between the two filters there are
two plastic valves with the drain hoses, are these the bleeders
as well? There is another plastic valve downstream of the fuel
separator as well. When I crack that valve open and manually
pump the primer, fuel sprays out. When I open the two valves
on the filters I sit and pump forever and nothing sprays out.
Am I mistaken these drain valves for bleed offs? Or is the
bleed off an actual metal bolt/nut?

AJ. · Apr 8, 2017

Those hoses are for draining the filters,the bleeder should be on the R/H side of the filters looking at them,it's a steel nut about 11/16 wrench size, open it and pump till clear fuel comes,close the bleeder, pump on till it goes stiff and lock it,try to start,they can take a lot of winding over to build up enough pressure for them to go.
AJ

Mission Creek · Apr 8, 2017

Great, thank you. I could hear air bleed down when I would
open them up after priming but wasn't sure. Thanks again

Cat loader reprime

Mission Creek

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dpendzic

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warbaby

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AJ.

Well-known Member

Mission Creek

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AJ.

Well-known Member

Mission Creek

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