Fuel on the Deck 6.5TD: Fuel Filter ASSY Leak??

[Stratosurfer]

I have a very slow fuel leak (weep?) that hits the garage floor just below the rear of the bell housing. This is my 98 Sub 3/4 ton. After weeks of diagnosing and mopping it up w/Simple Green I have determined that it most likely is dropping down from the connections on the OEM fuel filter assy.
My question to the vets is how complex is the fuel filter in removing the entire assy?
Also, are the lines clamped rubber or what, I want to have access to proper materials if an entire length of line needs to be replaced.
Any feedback/help appreciated.
Thanks
Mark B. Magee
Brady TX
98 SUB LT .75 ton 6.5TD
97 Tahoe Govt. Model 6.5TD

[tommac95]

Steel lines {OEM config} run up along bell hsg , 3/8" feed, 5/16" return. A short length [6-8" ?] of fluoroelastomer-lined neoprene fuel line [I think SAE30 J R9] connects these lines to the return steel tube along psgr side head/InMan boundary, and the input to the fuel conditioner assy between rear horns of InMan. Typical screw-hose clamps held mine. Two 1/4" lines run forward from conditioner to FIP {molded} and water-drain valve on thermostat bracket. Access to the fuel conditioner assy with the InMan mounted is very poor, obscured by rear wire harness support bracket ....Access to the short hoses at connection to bell house tubes is worse.

The conditioner is a tube with a screw-on top(holds filter) and bottom(holds heater). It may (or NOT!) be worth trying to lift the conditioner enough to tighten the bottom hollow-plastic-nut , or even renewing the oring that attempts to maintain the seal here. IF your fuel conditioner's heater component has a steel (plated) cap , it'll likely leak thru the wire connection; if a plastic (later-style) cap, probably OK.

If you don't mind spending $100+ , it doesn't hurt to renew/rebuild/relocate the fuel conditioner . I cheaped out and rebuilt/relocated, moving out of engine compartment.

Leaks into the vee-8 valley drain thru a hole to bellhouse interior vicinity. The little return hoses from the fuel injectors can also leak, esp the end-of-line plugs.

[Robyn]

Well lets get at it.
Start by getting a suitable peice of plywood and some "OLD" blankets to protect the fenders. Place the plywood across the engine so you can lay on your belly and get comfy to work at the rear of the engine.
The fuel filter assy has two electrical plugs that are held by the little bracket at the rear of filter assy.
undo the little snaps that hold the plugs into the bracket "carefully" then you can use some small bungy cords to "Gently" pull the wiring harneses up and out of your way. The two smaller plugs go to the filter, one is the heater the other is the water in fuel indicator. Unplug them.
Unbolt the filter assy (2 bolts) and remove the bracket from under it and set aside.
Now you have a little more room. The best way is to plan on replacing all the lines (Rubber) cut loose the feed line to the Injector pump at the pump and the water drain line at the front. The two lines at the back are tight but doable. Best plan is to use a pair of side cutters to get the old ones out and then you can remove the filter assy. Now you have plenty of room to get at the rest of the old lines in the back and remove the remaining old hose.
Check the filter assy and repair as necessary. Use the Molded hose for the fuel feed from the IP to the filter. All the rest of the lines are just fuel hose.
If you dont mind the $$ use fuel injector hose as its tougher and you wont need to redo it most likely any time soon. *** a word to the wise*** When you snake the new IP feed line down the valley be sure and plug the eng you shove through from the front so as not to fill the hose with dirt from the valley area. Duct tape works great for this or stick a bolt in the end to plug the hose.
Also be sure your leak is not coming from the Injection pump and running back.
You need to leave the area sloppy so you can see for sure.
This is not a daunting task but if you just work carefuly you can nock it out in a couple hours and be set to go.
Once your all hosed back up, bleed out the air all the way to the IP and the drain line too and you should be all set.
I leave the IP line off and bleed into a small can untill fuel is clear of air then I do the filter top bleed and finally the drain line. Even after this you may have a sloppy runner for a short time untill all the little bubbles are purged (a minute or so)
Good luck and keep us posted.
Robyn

[Stratosurfer]

I am considering 'relocating' the fuel conditioner now that it has to be serviced. It seems to be an an awfully tight spot, should it have to be serviced again in the future....
Anyone moved the filter assy anywhere else more convenient? I was thinking about in front of the anti-lock solenoid on the LH fender well.
Thanks for the data boys, do either of you or anyone know the diameter of the fuel lines to be replaced?? This would be wonderful to know before kicking this project off out here in the sticks.
Thanks for all

[Robyn]

Inlet to the filter from the tank is 3/8 and the return is 5/16
The drain line from the filter is 1/4 and the delivery line to the pump is 1/4 I believe. I replaced my delivery line with the factory molded one.

[Stratosurfer]

Robyn and Tom,
Thanks, I have just moved out truly 'Deep in the Heart of Texas", and am trying to find -anyone- who works on/has familiarity with the 6.5TD. Fortunately there is ONE mechanic in McCulloch County Tx, a former Mr. Goodwrench that claims familiarity and affinity with the 6.5; I decided to sub this job out to him.
Thanks for the input from both of you, the mechanic was in complete agreement concerning moving it and will fab a bracket to move it to the LH fender forward of AB brakes solenoild.
Thanks again.

[Robyn]

Smart move.
while your in the mood to move stuff. chop the fuel lines loose off the back of the engine where they are almost impossible to get to and run them from the electric pump area under the floor boards and up under the column area. You can easily reroute the return line from the right side of the engine via hose over the left valve cover and to the new location. also this will make plumbing your relocated filter easier too.
Good luck
Robyn