My CUCV spin on fuel filter mod

Pawnshop

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OK, my stock box type fuel filter base was leaking (reportedly from a cracked housing) and being an overall PITA so I decided to convert to a spin on type filter arrangement. I searched here and online for photos and advice on the subject and came up dry so I decided to wing it, and I think it worked out OK. If anyone sees a potential problem with my setup PLEASE say something, I am no fluid dynamics engineer, nor am I a mechanic!

My parts list: (total cost about $100)
1-NAPA fuel filter base, pt#4309
1-NAPA fuel filter/water separator pt#3123
2-1-1/2" or 2" bolts, 3/8" coarse thread
2-big azz nuts
2- 1/2 NPT male to 3/8 hose barb fittings
1- 3/8 to 3/8 hose barb splice
1-3/8 to 1/4 hose barb splice (I had to make one)
6-hose clamps
12" of 3/8" fuel line (approx)
fuel resistant Teflon tape

I got the fittings from Home Depot, in three trips (don't ask)

I pulled the rear batt to get to the old unit (and that kills the sparkies in the area), pull the two fuel lines off the left side of the old filter housing REMEMBER (or make a note) the top/bigger one is IN from the tank and the bottom/smaller one is OUT to the motor (I clamped the lines shut with vise grips to reduce air in the lines, don't know how necessary that is), remove the three bolts holding the bracket to the firewall and pull the old filter and housing out, being careful not to get too much fuel all over the place as there is about a pint in the filter (NO SMOKING).

The mounting holes in the NAPA bracket ALMOST line up with the holes in the firewall (1/2 hole dia too narrow) and are too small to run the mounting bolts trough (that would be too easy) but thankfully the bracket is aluminum and easily modified. I used a cone shaped burr on a drill to enlarge and widen the holes then I discovered that the 2" bolts I got would not clear the housing so I angled the holes a bit till they went in (that is why I called for 2" OR 1-1/2" bolts). The bracket is thick and the holes are not so close to the edge that they weaken it to modify them. I used longer bolts because I discovered there is an electrical thingie sticking out of the firewall that the filter has to clear so I had to make the bracket stand off the firewall about 1". I did not have a piece of aluminum block to make a spacer so I got two of the biggest nuts HD had and that was just enough to make it clear.

Once the bracket is firmly on the firewall the two 1/2" NPT male to 3/8 hose barb fittings can be installed on the new housing, be sure to teflon tape them good. The next time (if there ever IS a next time) I think I would try to find one 1/2" NPT male to 1/4" hose barb for the outlet side, if it exists, to reduce the fittings necessary for the reduction to follow. Use the 3/8 to 3/8 hose barb splice to add about 6" to the bigger inlet line and hook it to the right/IN side of the housing and a 3/6-1/4 hose barb splice to extend the smaller OUT line to the left/OUT side of the housing. I could not find a 3/8-1/4 hose barb splice so I made one from a 3/8 barb/1/4" NPT male threaded to a 1/4" barb/1/4" NPT female with a lot of teflon tape. If you can find a 3/8-1/4 barb splice that would be better, OR go 1/4" all the way to the housing if you can find a 1/2" NPT male with a 1/4" barb on it and a 1/4-1/4 barb splice and some 1/4 fuel line. Hose clamps at all the junctions of course. You could also just run new lines from the tank and to the IP if you want, that would remove the need for splices completely, I was lazy and did not do that (maybe later)

Once the lines are all tight, fill up the fuel filter with fuel and lube the gasket and spin on the filter tight and put you battery back in. Remove the pink wire from the injector solenoid (and the vice grips from the fuel lines if you have not already) and crank her over a few times to move the air through (it won't start with the pink wire off), check for leaks, fix leaks as necessary (I had to), connect pink wire and START! Let it run a bit looking for leaks, if no leaks then you are done! I had leaks (my teflon skilz are weak).

Clean up, police your tools and get back in the AC!

Again, if you see something I have done wrong, or a way to improve my design, PLEASE speak up!

Your individual results may vary, thanks for tuning in.
 

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stampy

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Hey! I did the same thing! I used the old bracket to move it away from the firewall so no rubbing...just a thought. Oh I got mine at walmart too.:-D
 

Pawnshop

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My wallyworld does not sell them, had to go to NAPA. I thought about using the stock bracket for offset but that would have put the filter too low and there would not have been enough clearance over the valve cover to get the filter off, and I thought it would get warn that close to the motor.
 

dieselpony

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Stuttgart, Germany
Nice Setup! :!:
2 Questions though:
- is there an electrical connection on the fuel/water separator to work with the dash "water in fuel" light?
- does the filter have a heating element like the box type?

Walter
 

Pawnshop

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NO and NO. Down here in Central Texas it doesn't really get "cold", the lowest I can remember was 9 degrees F, the lowest this past winter was about 20, and that was only for a few hours so I don't think I will need a fuel heater (I hope).

As for water in the fuel, I think that is more of a contamination/storage issue. This M1009 is my daily driver so it will not be sitting for long periods of time gathering condensation in the fuel tank, and the fuel stations that sell diesel around here sell enough of it that their tanks are turned over frequently so I think my chances of getting water in my fuel are slim (I hope)

We shall see! I have not done any permanent mods to the truck so if I feel I need to go back to the stock unit I can.
 

acmunro

Member
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Location
Reynoldsville,PA
Looks good, the filter you are using looks like the primary filter used on the 1982/83 6.2 diesels. They also used a secondary filter mounted on the intake manifold. I am not sure of the micron rating.

I have also been gathering parts for this swap. My Napa said they don't have listings for filter bases. I guess now that I have a part number I could get one. Thanks.
 

acmunro

Member
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Location
Reynoldsville,PA
Spin on filters are 10X better IMHO. I have no problems with my trucks with spin ons. I only have 2 trucks with the box style filters that work properly. All others with box filters have problems. They are getting converted.

BTW 82 trucks had the water sensor in the fuel tank.
 

ken

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I unstalled a squeese bulb for a outboard motor on mine. that way filling the filter is alot easier and less messy. Just open the bleeder and squeese it a few thime and it's full. Alot easier on the starter too when you have to work on the fuel system. Bleeding out the air is a snap.
 

69dieselfreak

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instead of using the marine bulb thing idea i wish i had a picture
caterpillar makes a fuel filter head with a primer built in i think that they came on 3406 B C and also the E models but its a thought
if you guys want me to get pics i probly can let me know
 

Chief_919

Well-known member
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Western NC
My civilian pickup with the 6.5 has an electric pump that makes changing filters a breeze, that inspired me to install electric pumps on all my CUCV's I have owned.

Flip the switch, push the air out, flip it off. As a plus if your mechanical pump ever fails, the electric is right there and will work just fine. Any time I have had a mechanical pump fail I just removed it and ran just the electric.
 

cjkeeliii

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I gots to have dat! I was outside a few nights ago --by myself--with an aquarium hose hooked to the bleeder nipple, leading into a diesel can, trying to prime the pump after changing the filter.
 
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