Secondary Fuel Filter

[mark_53]

Anyone have a good technique for changing the secondary fuel filter on a M25XP without spilling diesel?

[KWKloeber]

Since the filter is vertical I am just very careful when dropping it.
Put a diaper under the area - when the filter is finger loose slide a gallon baggie up and finish unscrewing the filter.

[mark_53]

Thanks Ken sounds like a good technique.  Is it possible to pour the diesel from the old into the new filter or will diesel continue to flow when the filter is removed?

[KWKloeber]

Don't see why it wouldn't be "possible" but probably messy.
But why?  You're going to bleed and the facet will fill the filter. I've never pre filled my primary or secondary and never had a problem.  Others' mileage may vary.

I have my bleed set up a little different than yours - I KNOW when I have foam or pure fuel and so don't need to guess when enough bleeding is enough. 
FYI there's a bleed screw on the secondary's housing but I've never had to use it.

I can't say how your lines are run. On my 30 i have a high hump in the fuel line before the secondary, so a limited can drain if the facet isn't pushing fuel to the injector pump.

[mark_53]

Don't see why it wouldn't be "possible" but probably messy.
But why?

I was trying to solve the problem of what do I do with the refuse diesel.

You're going to bleed and the facet will fill the filter. I've never pre filled my primary or secondary and never had a problem.  Others' mileage may vary.

Is bleeding necessary with an electric fuel pump?

I'm trying to find out if diesel will continue to flow when I remove the secondary fuel filter.  If it does, I won't have time to do much of anything.

[KWKloeber]

Again I can't say where/how your fuel line is run. It doesn't continue to "flow" only what "drains" depending on the elevation/run of the line.  Little drains from mine how I have it run. 

"Of course" you're closing the fuel shut off valve so none will siphon from the tank?

The type of lift pump has zero to do w/ bleeding.  Once you get air in the lines thru either a vac leak or changing filters, you want to bleed the air before it gets to the injector pump.  Otherwise you may need to bleed at each injector (a PITA.). The pump and injectors don't like air or foam.

I'm sure there's a 101 or tech note somewhere about the fuel system if you're unfamiliar with the procedure on the M25/XP.  Do you have the manuals?  They should cover bleeding.

When I bleed, fuel goes into a Solo cup so I can inspect it, then gets stuffed with paper towel to soak it up, then into my baggie with trash filters.  No muss, no fuss, no drips, no runs, no errors, no one left on third.

[Jim Hardesty]

Anyone have a good technique for changing the secondary fuel filter on a M25XP without spilling diesel?

You may be doing this, may be not.  Try shutting the fuel off before changing the filter.  Also keep an eye out for the right size and shape containers for filter changes.  Also I've used ziplock bags around filters, put on the bag, remove filter, zip-up bag.  Sometimes regular bags will work.
Jim

[scgunner]

    Mark,

      There's no way I know of to change that filter without at least some dripping. As long as the ignition is off there is no fuel flowing so you can take your time when changing that filter. What I do is put rags below the filter to keep any fuel from dripping into the compartment, next I hold a bowl under the filter while unscrewing it. Once the filter bowl is free I pour it into the bowl then I change the filter element next I pour the fuel back into the filter bowl, then put the new filter assembly back into the element bowl and screw it back into place. Wipe everything down and you're good to go, I usually don't even need to bleed it.

[mark_53]

Thanks Kevin that sounds like a good technique.  Do you shut off the flow of diesel with the fuel shut off valve first?

[mark_53]

Got er done. Some lessons. I did not want to deal with the fuel shut off so I left open.
1) Used a 11.3 oz plastic coffee container that fit just over the old filter. Unscrewed the filter and diesel fell into container.
2) Diesel kept slowly flowing.  Quickly installed new filter.
3) Started engine which ran for 10 seconds and died. Oh well, so much for short cuts.
4)Turned ignition to on to activate electric fuel pump and bleed the filter until good flow of fuel came out. Caught this fuel with coffee container and bilge rags.
5) Tried to start engine. No joy.
6) Activated electric fuel pump and turned the knurled knob on the injector pump. Electric pump ran but no fuel escaped. This is because my engine has a self bleeding return valve.
7) Engine started

Thanks guy's for the tips.

[Ron Hill]

Mark : It has been posted MANY times - to fill the filter with diesel before you screw it ON.  Then do the bleeding procedure by loosening the bleed nut on the top of the filter holder!!

A few thoughts

[Stu Jackson]

Mark : It has been posted MANY times -

1.  to fill the filter with diesel before you screw it ON. 

2.  Then do the bleeding procedure by loosening the bleed nut on the top of the filter holder!!

1.  Completely unnecessary for the secondary engine mounted filter.

2.  Once the new filter is in place, you WILL need to partially unscrew the vent on the secondary filter housing.  I installed a fuel pump shutoff toggle switch right next to the pump so when the fuel start pouring out of the screw I can easily shut off the pump, close the screw and finish bleeding.

As Ron always says, "Only do ONE thing at a time, so if something goes wrong at least you'll know for sure that it's the last thing you did instead of wondering which of two or more things it could be."  Very wise advice.  Do ONE filter at a time, make sure the engine runs, then go do the other filter.  Doesn't matter which one goes first.

And again, for grins & giggles, I finally changed my primary filter after 900 hours.  I haven't changed the secondary in decades.  This may start a sh*tstorm, but I use a 2 micron on the primary.  After those 900 hours, it was still almost spotless.

[KWKloeber]

Stu you've gotten some nice CLEAN fuel.

How many do you know that have to bleed at the secondary housing?  Is that typical?
I have NEVER ever bled there- the only bleeding I've needed to do is using the bleed knob/valve (formerly bleed hex bolt) before the injector pump. Wouldn't that be bleeding the same thing, but just a little further downstream?

Is that a 2u Racor you're using?

[Phil Spicer]

   Stu, you must be living right, 900 hrs on your filters. That 2 micron is doing it's job.

[Stu Jackson]

Stu you've gotten some nice CLEAN fuel.

How many do you know that have to bleed at the secondary housing?  Is that typical?
I have NEVER ever bled there- the only bleeding I've needed to do is using the bleed knob/valve (formerly bleed hex bolt) before the injector pump. Wouldn't that be bleeding the same thing, but just a little further downstream?

Is that a 2u Racor you're using?

We have owned Aquavite for 21 years.  We have purchased fuel all over Northern California, up the coast and in BC and the San Juan Islands.  Just my dumb luck.

All I can tell you is what MY experiences have been.  Other than depending on our "Bleeding 101" guru, Ken Heyman, our C34IA Treasurer who "wrote the book" on primary filter bleeding, my points here are about the secondary, which was not covered in Ken's presentations.

All I can share are my experiences, since I rarely get into that arcane subject around the cocktails. 

I have shared these thoughts here before, too, and am pleased to re-contribute them.

Perhaps I wasn't patient enough the first three times I changed the secondary, but my experience is that the engine wouldn't start UNLESS I popped that screw.  Theoretically, if I waited long enough for the pump to run it all the way through the system, sure, you're right.

Yes.