Fuel filters and lift pumps

[Glenn Scherrer]

I have a 1998 patriot with a cat 3126 I am going to change out my primary fuel filter system It has the old Parker system with the pump built in the filter housing and the plastic filter housing with the screen no part around to service this unit so I want to replace it with a new filter housing does any one know the size of the inlet and outlet of the fuel lines  also do I need a pump to prime the system when I change the filter if I fill the filter up before installing ?   Also does the 3126 cat have a lift pump l

[Gerald Farris]

Glenn,
All of the parts that are necessary to service your primary fuel filter and priming pump system are still available with the exception of the electric pump. So as long as your electric priming pump is still working, there is no need in replacing your primary fuel filter system.

Gerald 

[Dave Atherton]

Glenn, the Cat 3126 has a fuel transfer pump that takes the fuel from your Racor
Filter setup and sends fuel to the Cat 1R-0751 fuel filter under pump pressure. One
thing you need to check for the entry of air at this Racor filter setup into the fuel
system of which with is starting to show up on many motorhomes. Like Gerald mentioned
most parts can be found. We have started to retro fit engines with HEUI injection
systems with a Cat fuel pump setup as per owner request.One of the main problems in present fuel
setup is low power with the heui pump because lack of constant fuel flow and fuel
pressure. In most cases problem has been entry of air at Racor fuel/water filter
Racor filter setup needs attention. With the Cat C12 and up the fuel system has a gear
fuel transfer pump that is different than Cat 3126 engine and up.
Dave Atherton Retired Cat Mechanic

[Glenn Scherrer]

Were is the transfer pump. Located on the 3126 cat ?      Is it electric pump or mechanic pump?    If it's electrical can you run it by turning on the key or some other means ?       

[Dave Atherton]

Glenn, on Cat 3126 the fuel transfer pump location is on the back of the HEUI pump. Looking
at your discharge fuel line ( hydraulic hose used for fuel line ) from Heui pump to the secondary
Connection to engine fuel transfer pump is the top hose. The lower ( hydraulic hose used for
Fuel line ) is the suction hose from the discharge side of the fuel/water filter Racor setup. Again
if fuel system is setup correct ( the secondary 1R-0751 fuel filter will be under pressure of the
fuel transfer pump sending fuel into the cylinder head. Dave Atherton Retired Cat Mechanic

[Dave Atherton]

Glenn, your fuel transfer pump is a mechanical pump that is powered off engine HEUI
Pump. I have a suggestion before you spend a lot of time, to check the Racor fuel/water
Filter on the discharge side for exit of air ( this can be done by using about 10 inches of
Clear plastic hose that can be found in the hardware dept.) connect discharge side of water/
fuel filter than to suction fuel line going to fuel transfer pump. Start engine and see if there
Is a clear stream of diesel fuel with no air showing inside plastic hose. Note: any air present
you have a problem. Second step remove fuel line to suction side of fuel/water filter and
connect clear line to fuel line coming from fuel tank, again if any air bubbles present. If
Not your problem is now located to the Racor water/fuel filter. Gerald explained the Racor
setup will need attention. Dave Atherton Retired Cat Mechanic