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LML Fuel Filter Relocation

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I wanted to share something I hadn’t seen done using a kit I found online by coincidence back in the spring, relocating the stock fuel filter for easier access.  A few things first:  I’m in no way associated with this company, I bought the kit and found it to be a good one and would like to pass this on to other folks who may be interested, I only found limited information on the net out there now.  Keeping the stock FF in place even when running a lift pump is important if you running the stock CP4.2 fuel pump.  The stock filter is hard to beat, it’s one of the best on the market and adds another level of security against contamination, esp. WATER.  We all know the stock location of the fuel filter is not the easiest to access, on the earlier trucks it could be accessed from the top with a little effort, but not on the LML’s.  I have the Madjack access door installed on my fender liner, as I got tired of stripping out screws taking out the liner and had to buy new ones from the dealer.  That works OK, but it’s still a pain and screwing with the o-ring isn’t easy from below when you can’t see it laying on top of the passenger side tire putting the new filter on.  So, via a google search, I found a relocation kit from a company called Western Diesel located in Arizona.  All that I could find on the net about it was a Youtube video (which is nicely done btw) showing the kit being installed on a LMM.  I contacted Western Diesel via phone to discuss, and have had nothing but good conversations/and experience with them each time I spoke with them, even after I ran into a bump during the install.  I bought the LML kit and they promptly shipped.  The instructions were good, but watching the Youtube vid was definitely helpful.  You will need to remove your air intake elbow prior to starting.  I have an S&B intake, I just removed the elbows and left the box with filter, it was not in the way at all as seen in the photos.  I also worked completely from the top, no need to open up the fender liner.  Tools needed:  15mm socket with extension, 1/2” closed end wrench (non-ratcheting – stubby works best), 1/2” socket, needle nose pliers for removing hose clamps (the long ones with a 45* bend-these are a must!), gloves (you’re going to get fuel on you).

Here is my install:

Here’s the relocation bracket, a nice heavy piece:

46104383961_2441915535_k.jpgIMG_7784 by Brandon Needham, on Flickr

45380396254_10bc5a51a6_k.jpgIMG_7786 by Brandon Needham, on Flickr

Here’s where it goes:

44288137990_0afa7681ca_k.jpgIMG_7783 by Brandon Needham, on Flickr

Bracket Installed, pull it as far forward as you can get it and tighten:

44288137150_5518f366dd_k.jpgIMG_7788 by Brandon Needham, on Flickr

46104383051_726a76a6a4_k.jpgIMG_7787 by Brandon Needham, on Flickr

Next comes the fun part, the hardest part of the install (not really that hard), removing the filter from its stock location.  Removing the air intake elbows and unplugging as many sensors to pull the wire harnesses out of the way will give you room to work.

46054291832_c998742b6b_k.jpgIMG_7812 by Brandon Needham, on Flickr

45192657505_fa3aaed87d_k.jpgIMG_7813 by Brandon Needham, on Flickr

With everything unplugged and out of the way you’ll be going after the two fuel hoses attached to the hard lines beside of the alternator.  TIP, take a pic with your phone before you remove anything to remember which hose is which and also mark them, you don’t want the fuel to flow through the filter backwards.  I took the below photo before I unplugged the harness in the way shown in the photo, once its unplugged, there is room to work.  With the hose clamps removed using the long 45* bend long needle nose pliers I still had to cut them down the middle with a razor to get them off.  I stuffed as many rags as I could under the hard lines and hose before pulling them off, this kept fuel from getting on everything.  I folded the hoses still attached to the filer to pinch them off and put a zip-tie around them to keep fuel from spilling out when I was ready to pull the filter out from the top.  This worked really well, I barely got fuel on anything except my hands.

45380393904_1f75b2a09b_k.jpgIMG_7815 by Brandon Needham, on Flickr

32233051878_cebb7fb0b6_k.jpgIMG_7819 by Brandon Needham, on Flickr

Next, it’s time to remove the filter and its head from the stock bracket.  To do so, you must first unbolt the coolant line bracket that’s in the way:

45192655975_6dafc5686d_z.jpgIMG_7817 by Brandon Needham, on Flickr

Next, the hardest part of the install, removing the two ½” bolts holding the filter head to its bracket.  There is not much room to work and a socket nor ratcheting box end wrench will fit.  I used a stubby ½” boxed end wrench to get bolts out, you will have to pull the coolant line towards you (towards the filter head) to get to them.  Don’t worry, the line is connected to hose on both ends so it moves.  Be sure to unplug the WIF sensor from its connector on the truck before you take the last bolt out.  With both bolts removed I rocked the filter back towards the firewall (remember we have the lines pinched off and zip tied), pushed the hard coolant line towards the engine and pulled the filter attached to its head straight out the top.  Re-bolt the coolant line back to the bracket it was previously bolted to.

Filter with head removed:

46054280622_0168a182e6_k.jpgIMG_7832 by Brandon Needham, on Flickr

Next it’s time to install the new hoses.  I flushed my new hoses out a few days before with non-chlorinated brake cleaner and them hit them with compressed air, hung them to dry and taped the ends to prevent any contamination.

45192661525_59642d7d64_k.jpgIMG_7807 by Brandon Needham, on Flickr

I took this extra step on my own accord since the hoses are going to route behind the alternator to protect them.  I already had this material on hand and have used it before in several types of applications, you can buy it online a few places, wear gloves if you mess with this stuff, the fiber glass in it is very fine and will stick in your hands for days (I know from past experiences):

45192661685_fa737096d7_k.jpgIMG_7804 by Brandon Needham, on Flickr

46054294912_cfea3b77ac_k.jpgIMG_7805 by Brandon Needham, on Flickr

45192660245_4c67ed2374_k.jpgIMG_7806 by Brandon Needham, on Flickr

31165031767_48b19ea820_z.jpgIMG_7808 by Brandon Needham, on Flickr

Connect the back hose first and route it behind the alternator like so, leave it full length, then do the same thing with the front one – MARK YOUR HOSES (I took this pic after I already plugged the wire harness back in, again with it unplugged there is more room to work than the pic indicates):

45192658835_def7403a85_z.jpgIMG_7811 by Brandon Needham, on Flickr

46054288372_c592dd3938_z.jpgIMG_7828 by Brandon Needham, on Flickr

45192653275_e1bede0434_k.jpgIMG_7834 by Brandon Needham, on Flickr

45192651245_60e29f9d78_z.jpgIMG_7833 by Brandon Needham, on Flickr

I then changed my fuel filter and removed the factory hoses still attached over an oil drain pan so I wouldn’t get fuel everywhere.  With new filter installed and factory hoses removed, I attached the assembly to the new bracket pulling it as far forward as possible using the provided hardware and a ½” socket:

45192649155_91c2955365_k.jpgIMG_7835 by Brandon Needham, on Flickr

45380384834_6206d50030_k.jpgIMG_7836 by Brandon Needham, on Flickr

Mockup your hoses and cut the extra off, I cut mine a little long the first time on purpose to check the fit.  After the hoses are connected I ran the new WIF harness beside the hoses and connected it back to its factory connector at the original location.  I used heat resistance Zip ties to secure everything:

46054282192_9a67ed46f2_z.jpgIMG_7842 by Brandon Needham, on Flickr

45192645655_1dca0c52e7_z.jpgIMG_7843 by Brandon Needham, on Flickr

45192647615_6b18c22e22_z.jpgIMG_7839 by Brandon Needham, on Flickr

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WIF harness fit perfect with factory connections:

45192659095_243031fc31_z.jpgIMG_7810 by Brandon Needham, on Flickr

46054293522_b6e9b26400_z.jpgIMG_7809 by Brandon Needham, on Flickr

45192648605_0a4245bbfc_z.jpgIMG_7838 by Brandon Needham, on Flickr

Now, reinstall your air intake and wiring harness to all the sensors.  Prime the crap out of everything like normal and fire it up. 

Final pics of the install showing clearances.  Disregard my pressure sensor in the bleed port on the filter head, I read lift pump pressure on my CTS2 at this location.

45192646865_ed6fae025a_z.jpgIMG_7841 by Brandon Needham, on Flickr

45192645655_1dca0c52e7_z.jpgIMG_7843 by Brandon Needham, on Flickr

45192645745_02dfc86861_z.jpgIMG_7844 by Brandon Needham, on Flickr

45192643945_d6791d2172_z.jpgIMG_7845 by Brandon Needham, on Flickr

46104363561_7be6da3bfc_z.jpgIMG_7846 by Brandon Needham, on Flickr

So far I would recommend this kit.  I’ll do an update about a year from now when I change my fuel filter.  Hopefully that filter change will be much easier than the ones previously.  I’m not saying changing the filter in its stock location is hard, but it’s a PITA that’s unnecessary for being a general and very important maintenance item for what it is.

Let me know any questions of comments!

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Meant to respond to your post over on the Duramax forum the other week and forgot. 


I looked at this setup awhile back, but it doesn’t work with dual alternator trucks since that is where the 2nd alternator is located.

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