Primary Filter Question

[nhdiesel]

I'm in the middle of a filter change and found something odd. I just got done doing a search and reading quite a few threads, with no answer to my question. First of all, my primary has a tall can that looks similar to the secondaries. I read in a coup;le threads how this can be good to allow more room for crud to accumulate on the bottom. I'm good with that. But what confused me is that there is no seal on the bottom of the filter!

Basically the empty can has 4 springs stacked up in it, then the filter sits on top of those. The springs hold the filter up against the housing. The problem is, the only way to ensure that the filter is actually filtering is for the bottom of the filter to be sealed so that the fuel has to go through the filter. Without any type of seal, the fuel just flows into the can, then up through the openings at the bottom of the filter and out of the filter housing.

This probably explains why the filter was very clean with very little in the bottom of the can.

Please tell me there is supposed to be something sealing the bottom...otherwise the primary filter does nothing!

Jim

 

[barnetc1]

I just did a complete fuel filter change, and the one i took off the truck was like you explained. The replacement filter that came in my kit is completely enclosed, but it is shorter than the original. I guess this is ok, because other people talk about the replacement filter being shorter. I installed it like the old one came out.

 

[Floridianson]

Seen this more than once. People when you get these trucks check and change the filters.

Your should have in order from bottom to top a washer a spring a washer then a brass looking cup faceing up that seals to the filter.

 

[nhdiesel]

Well it looks like no rally for me tomorrow. Because one of my secondaries was installed wrong, instead of 3 filters, my fuel was only going through 1 filter. No wonder 1 filter was dark (far from nasty, just darker) and 2 were very light and clean looking...they weren't doing anything!


Thanks for the info. Guess I have to get parts from my other truck, which is 100 miles away.

Jim

 

[DieselBob]

Sounds like you are missing *a. This should be the cup that Floridianson mentioned.

 

[nhdiesel]

This is all I have:





I looked inside the can, and it looks like the center bolt has a step on it. My guess is that a washer is supposed to stop on that step and hold the spring and filter. Instead, mine has 4 springs running all the way to the bottom of the can.

Jim

 

[Floridianson]

The ones I have have cork around the bottom no holes. Also the one washer has rubber washer. I will get the napa number for the filters I use. I also think I have some brass cups on parts trucks. If you need them I will check and give them to you. Done this for outher members.

Sorry Jim the mechanic must have smoked the good stuff before he worked on your truck.

Found it 3511 napa

 

[jatonka]

The ONLY primary filter cartridge that is correct mil spec is NSN 2910-00-790-2300. The napa 3511 is not the same. The original poster was missing the cotter pin, washer, spring and brass cup . I have seen many different errors in the trucks I have bought and gone through in the past years. Get a parts manual, you should have gotten one and read it when you bought the truck anyway, and if you don't have the right parts in order in the canister, contact me and I will set you up. JT

 

[nhdiesel]

I tried to reply back earlier but I guess it never showed up. I'm back in business. I made a seal and washer assembly which seals against my Napa filter (the one in the photo was the original that I had removed). I spent 10 years as a precision machinist in a tool room, fabbing custom parts to repair machinery is what I was good at. I used a washer from an old off road light which fit on the Napa filter and centered it on the shaft/bolt perfectly. I then used an O-ring and another washer to make sure the washer was sealed to the shaft. I bet my setup will seal better than the factory parts I'm missing, so I'll be going to the rally tomorrow.

After the rally I'll probably be driving it straight to my father's where I'll replace the missing parts with the correct parts he has. The truck was driven 1500+ miles with the missing parts and one unseated secondary filter. I'm sure I'll be fine with the seal I made and 2 well-seated secondaries.

Jim

 

[nhdiesel]

Well I was almost back in business. I got it all back together but had to fight a couple leaks around the secondary seals. The new seal didn't sit all the way up in the groove, so lining the can up was tricky. Got that sealed finally, but while checking for leaks found another fuel leak...this one unrelated to the filter change.

Part of the intake heater control was leaking. It's a small device, looks like a solenoid, that hangs off the block just above the diff. I followed the lines back and it looks like it comes off the tank separate from the fuel line, so I'm going to unhook the line and install a plug for now. I'll have to look for new parts after I get back this weekend.

Jim