Changing fuel filters

moldmkr · 05-25-2009, 12:22 PM

I am changing the fuel filter and fuel separator filters on the MH. Started by draining the fuel separator. Got 3 quarts in a 1 gallon bucket and still not down to the clear part on bottom of filter. What am I missing? Should I change the regular filter first?
Thanks for your help in advance.
Hans

08 Itasca Meridian
350 HP Cummins
Freightliner Chassis

GaryKD · 05-25-2009, 01:04 PM

Hi moldmkr,
If yours is like mine (ISC 330), a spin on filter and water separator, I do not drain them. I pre-fill then spin off the old and spin the new filter on. Pre-fill through the small holes. I do the separator first.

CaptPat · 05-25-2009, 01:13 PM

When I changed the fuel filters on my MDT with a C series Cummins, I filled the new filters with fresh diesel, took out the old filters and installed the new. Didn't drain the old filters first.

Pat

moldmkr · 05-25-2009, 01:19 PM

I have an alliance fuel separator filter. The filter is on top with a clear bowl on the bottom. The instructions on the filter say to drain it first with the little valve on the bottom. I opened it up and let out over 3 quarts of fuel but the bowl on the bottom still shows full. There is no way that the filter holds that much fuel, I figured 2 quarts at the most.

I tried to spin the regular filter off. They must use gorillas at the factory to put them on. Haven't budged it yet. Will have to pop a can of spinach first.

moldmkr · 05-25-2009, 01:27 PM

Just went out and started to spin the filter off and fuel started coming out the top, so I tightened it back up for now.

Cat · 05-25-2009, 02:35 PM

Sounds like your fuel tank is above your water seperator. You might want to just put off changing fuel filter until you have the fuel tank almost empty. Then see if you can change the filters without losing alot of fuel.

You also might look at the fuel tank and see if they have a fuel shut off valve. Most do not but doesnt hurt to look.

moldmkr · 05-25-2009, 03:15 PM

I just filled up the fuel tank last weekend and it is basically full.

SteveG · 05-26-2009, 04:10 PM

On my 2004 Journey CAT C7 I only have a single water seperator/fuel filter. Since there is no way for me to re-prime the filter I have to change it by filling the filter. CAT, of course, says to change it empty to avoid the risk of injector contamination. To help prevent contamination while I am carefully pouring fuel into the little outside holes I plug the mail center hole with a PVC fitting. Can't remember the size but was happily surprised when I found a size that fit. May sound a little overboard, but the down side is clogged injectors which is expensive and always a hassel.

moldmkr · 05-26-2009, 04:20 PM

For those of you interested I got the fuel filters changed today. Here is the procedure I went through.

As you know I had problems draining the fuel water separator filter. Called the dealer. He told me to just keep draining. Drained almost 3 gallons off and no luck.

Called Freightliner and they told me I had a siphoning condition. Told me to take the fuel cap off. Drained some more, still no luck

Called Freightliner again and they told me to raise the back of the MH as far as possible. So I turned the MH around in the driveway because we have a slight slope. Raised the back of the MH using the manual mode on the HWH jacks. Raised it about a foot and I was ready to try draining the filter again.

SUCCESS

Another little tid bit I learned from Freightliner was to only change one filter at a time. The reason was to fill the filter with fuel before installing and then to run the engine to burp the air out of the filter. When you hear the engine burp you can shut it off and change the other filter. Repeat the burping on the second filter before you hit the road.

The main filter (not water separartor filter) has a plastic plug in the center. Fill the filter with diesel with the plug in place, so if you have any contamination in the fuel it won't go to the engine

Hope this helps for anyone else wanting to try this

Hans

GaryKD · 05-26-2009, 04:21 PM

Even when off, the fuel system has pressure in it. When you drain the water separator your not only draining the filter but relieving the pressure in the system. After pre filling the water separator, I spin off the old one and spin on the new one. You are correct there will be fuel coming out of the point of connection. However, after several years of doing this I can get the old one off and the new one on in less than 15 seconds. It is a mess, but it is better than letting all the pressure (fuel) out of the system. This also minimizes the air that is left in the fuel system.

I repeat the procedure for the fuel filter.

The filters from the factory are tightened way beyond the needed torque. I used a large pair of channel locks to get the original filters off.

David K · 05-30-2009, 05:20 PM

I have found that a spider filter wrench is the best item to use for the removal of the filters. They have three "fingers" that go around the filter from the bottom and then as one moves the socket wrench, the fingers will tighten against the body of the filter and "spin" it for removal.