LD28 Maxima Fuel Filter Replacement Procedure

[glenlloyd]

So you think it’s time to replace your fuel filter? Well if you don’t happen to have the FSM you can use this procedure to get you through.

First, identify the fuel filter head (black primer pump handle on top) located along the passenger inner fender opposite the IP.



Also, locate your water in fuel sensor wire (blue wire) coming off the bottom of the filter. Locate the bullet connector downstream of the sensor and slide back the rubber cover and disconnect the two.

Now if your filter has been on a long time or you don’t know how long it’s been on there you might be better off getting a filter wrench to help loosen it. First I would try to loosen it without the wrench, but if it doesn’t come loose you’ll want to use the wrench.

Once you have it loosened spin it off being careful not to damage the wiring to the sensor. With the filter free dump the contents into a separate container noting what particles come out. Mine had some chunky stuff in the bottom.



Next carefully remove the sensor from the bottom of the old filter. Do not discard the sensor, the new filter does not come with one. Also, pay close attention to the o-ring that the sensor uses to seal against the filter. I planned on using a new one but the assortment I had didn’t have one of the same thickness, so I reused the old one.



In my case the new filter was not the same length as the old one, and appears to be a bit larger in diameter.




Clean the o-ring seat on the sensor and the o-ring itself, and reinstall the o-ring in the channel on the mating surface of the sensor.



Install the sensor/o-ring combo into the new filter making sure that the o-ring stays put in the channel. Be careful here not to cross-thread the sensor when you reinstall, it's easy to do, and this is not a part you can run out and get from your local parts house.



With this completed you’re ready to install the new filter in the filter head.

Do not pre-fill the filter. This might be tempting but fuel through the filter travels from the outside in to the central core and from there up and out to the IP.

In my case the filter was a bit larger in diameter, which I didn’t think much about at the beginning, but when I went to install it I had to pull the filter head up a bit in allow it to thread on. Also make sure you keep the sensor wire moving in the direction of the filter so that it doesn’t get bound up. Once installed completely you can reconnect the sensor bullet connector.



With that done you can now think about priming the system. First get a small flat screwdriver and loosen the primer pump bleed screw. Next depress the black primer pump plunger slowly until fuel flows from the bleed screw. Reseat the bleed screw once you have fuel flowing from it. Once that’s done you need to move to the fuel return line from the IP headed toward the fuel tank.

Loosen the return line clamp, or rip it apart as I did, and remove the fuel return hose from the pipe mounted to the front frame rail. Place a container (I used a plastic glass) below the hose and continue to prime the pump with the filter head plunger until no more air gets expelled from the line. In this case I slipped a larger clear plastic tube over the black hose and moved the container up to where fuel covered the clear tube pretty quickly. Then I primed until no more air was expelled from the system. This operation didn’t take as long as one would expect since the pump was still completely filled with fuel.

Remove the tube/hose from the container, reinstall it on the return line pipe and clamp it down tight. This should conclude your fuel filter install and IP priming operation.

Alternatively, if you have a mighty-vac like Al and others have, you can avoid doing all of this priming by pulling fuel through the IP via the return line and avoid having to bleed the filter housing and the return line via the method above.

Additionally, if you get to the bleed portion of the operation and your filter head appears to be innoperative, you'll have to resort to the vacuum method for priming the system. I would recommend acquiring a vacuum pump, like the mighty vac, to handle this operation.

Also, the FSM recommends draining the fuel at the beginning by removing the sensor. I didn't go that route because there wasn't a lot of room under the old filter and I feared that fuel could potentially overflow the container and go all over everything.

Hope this helps everyone get their fuel filter tasks taken care of! If anyone found any errors in my procedure please post and let me know what I screwed up!

Steve a

[asavage]

Thanks for getting this procedure documented -- finally! I've been meaning to for coming up on two years.

Two points:

• I do not recommend pre-filling the filter, ever. I don't recall the filter top, but if you must pre-fill the filter, pour liquid only in the outside ring of holes (if it has them: again, I can't recall). If you want to retain that pre-fill info in the instructions, please bracket it and make it "your own", with some disclaimer.
• Need a sentence to warn about the possibility of cross-threading the plastic water sensor when installing. The threads are very easy to cross-thread, I've found, and it's not like you can get a replacement on a Sunday afternoon.

Good work, Steve!

[glenlloyd]

Both those items have been dealt with as you recommended.

I removed the part about pre-filling completely. I had originally thought that fuel travelled down through the center and out through the perimeter holes, but with this filter that's not the case.

Thanks for the correction on that Al.

steve a

[Carimbo]

Great procedure!

Did you perceive how the drain works? i.e. when you drain the dregs out of the filter as per the FSM maintenance schedule. They have you loosen the sensor and pump the dregs into a small tub or onto a carpet piece. Does the fuel exit via the center where the wire enters the sensor or does it exit via the o-ring seal? I notice the sensor "nut" on mine is always wet with fuel weeping either thru the center of the sensor or past the o-ring, can't really tell. Suppose a possibility is that the plastic could be cracked because it is tightened down good.

[asavage]

I removed the part about pre-filling completely. I had originally thought that fuel travelled down through the center and out through the perimeter holes, but with this filter that's not the case.

I don't think I've seen a cylindrical liquid filter that filtered any way except from the outside toward the center.

There are a couple of air filter applications that put the dirty air into the center of a cylindrical filter though.

[asavage]

Does the fuel exit via the center where the wire enters the sensor or does it exit via the o-ring seal?

AFAIK, the sensor is molded to be one piece. Liquid is not supposed to move through it anywhere. To drain water, loosen the sensor from the filter's housing enough to break the o-ring's seal.

Your sensor may be leaking internally. Might be hard to know if it's the sensor or its o-ring though.

[glenlloyd]

I removed the part about pre-filling completely. I had originally thought that fuel travelled down through the center and out through the perimeter holes, but with this filter that's not the case.

I don't think I've seen a cylindrical liquid filter that filtered any way except from the outside toward the center.

There are a couple of air filter applications that put the dirty air into the center of a cylindrical filter though.

Logically, I don't know what I was thinking about, because you always want the maximum amount of filtration surface toward the substance to be filtered, hence the outer perimeter of the filter. Perhaps I scraped this up from VW, where they recommend you pre-fill the oil filter prior to installing on the vehicle.

It also could be that when I saw garbage in the center bottom of the filter, which I took to have been filtered out of the fuel on its way to the IP I was thinking fuel went down through the center and out through the media.

steve a

[Carimbo]

Logically, I don't know what I was thinking about, because you always want the maximum amount of filtration surface toward the substance to be filtered, hence the outer perimeter of the filter.

Also, the filter media is usually supported by the perforated cylinder in the center, no support on the outer side. This inner support is compensation to the pressure of the fluid passing from outside toward the center.

[glenlloyd]

Al and others,
Do we know what the micron rating is for this filter system?

thanks
steve a

[asavage]

I do not know the rating for the OEM filter.

The Wix replacement is 33476 and it is rated by Wix for 10 microns.

[davehoos]

I don't think I've seen a cylindrical liquid filter that filtered any way except from the outside toward the center.

this is something to be carefull of.with spin on fuel filters interchanging by thread and oring size internal filtering method has to be checked.

common filters are outside to inside.
you have to check the internal construction.
some filters are hollow in the center so you can see the switch float.others you cant see so the switch is in the primary section.
some types the filter is the old type cylinder with a cartridge idea so the fuel is drawn in and water and dirt collect and drops to the bottom.the modern type element the fuel enters the filter material flowing to the bottom.

720/D21 in australia have a 2 stage filter in one arangment.it uses a cheep spin on filter and a hollow sediment collector with a water switch.these rust out and are commonly replaced with a second spin on filter.the problem is that the 2 centers are conected.if the sediment bowl is fitted to the first stage[under the primmer pump] then the second stage is from inside to outside.i havnt a manual to check but mostly the filter is placed first and the sediment collector is there to notify you that your allready have problems.at this point the toyota shuts down the engine electrically.

large number of australian diesel uses have changed over to the LUCAS-CAV or copy system using commonly purchased adaptor kits.i find these can be hard to stop air leaks due to the number of orings and joins.
ive used a racor finer filter kits.Both these elements are now common as OEM.following the instuructions of a CAV fuel passes length ways through the filter cartridge with orings to seal the center tube.the fuel flows outside to inside.

I worked in landrover factory and we reworked the filters for the army to work in reverse.the same can be found when you examine other heavy equipment.this was done to extend service life in extreame conditions.the same applies to the CAV sediment bowl-fuel entered the outside section it hits a baffle the sediment hopefully drops to the outside and into the collection chamber.the fuel is then drawn from the top of this chamber-fuel stirs up the bowl and sediment is carried on to the filter.when fitted in reverse flow fuel is drawn from the highest point [reduced air] above a protective baffle.when the optional filter is used long life is asured often the need to change is dictated by corosion or material decompisition.

i have 2 nissan filters sitting in NZ waiting for shipping 1 looks like the item in the photo the other has a larger section with the pump on an angle.both have different non return valve setups.out of interest i looked up my recent nissan manual.the TD manual quotes that you undo the bleed screw on the filter.the RD manual quotes pump fuel until pump has bled then start engine-if engine runs rough race several times.there is no bleed screws you can hear the fuel retun to tank.

what i have done[common practise in worshops] is to have enough fuel lines to up turn the filter and bleed through the drain hose.

[asavage]

Nissan FAST lists two different Water In Fuel sensors:

• To Jun-1982 = 16412-V0701, $13
• From Jul-1982 = 16412-V3100, $13

A side-by-side photo would be appreciated. I can pull mine off the '82 Wagon and Mark's off his '83 Sedan I suppose. I'll see if I can remember to do that.

[asavage]

I've just ordered one of each. The one on my '82 Wagon has threads that do not look so hot. When I get them in, I'll take a pic for this thread.

[asavage]

Nissan FAST actually lists three Water-In-Fuel (WIF) sensor probes:



All Nos. turn into 16412-V0701, according to my dealer. So, though I ordered one of each, what I received was two of the V0701s.




Note that the WIF sensor probe does not come with the mating o-ring.

[davehoos]

can you measure the thread?
it looks like a water level sensor in radiator.

ive not seen a nissan sensor that small.