BearKiller

For several weeks, I had been noticing a faint fuel odor after anyone had been driving the son's truck.

A few weeks ago, I poked my head under there and there was a slight wetness coming over the side of the fuel-tank immediately under the fuel-bulk-head gizmo.

I sort of figured the short rubber piece on the RETURN line was old and rotten and that was probably the source of the very slow leak.

Then, all of a sudden, it got WORSE, REALLY WORSE.

I bet it was losing four gallons to the mile.

As the steel flat that we intend on installing is still mounted on another truck, awaiting time and muscle enough to swap it over, the sheet-metal pick-up bed is still on the truck.

I cut myself a generous trap-door hole immediately over the bulk-head and managed to do so without sawing through the tank or any lines and wires.

That sure beat the heck out of draining and dropping the tank or pulling the bed.

I kneeled right in the bed-floor and was able to see and access everything easily.


I fired up the engine and found a healthy stream of fuel spraying through a pin-hole in the metal RETURN-line, right up against the clamped-on rubber line.

No big deal I thought: for the present, I will just clamp on a new rubber line that is a couple extra inches long and slide the extra length an inch or so apast the pin-hole.

Mission accomplished and I fired it up again.

No more pin-hole leak; dry as a bone; all is well; let's go fix something else.

Then I hop down out of the bed to shut the engine off and see a flood of fuel pouring out from under the truck; where's that all a'comin' from.

Back up in the bed and poke my noggin down my new access hole and it looks like a shower-head under there; little spray-streams everywhere.

No problem; I replace the entire metal RETURN-line with a brand-new GATES rubber line.

Fire up the engine and no more leaks; leave it run quite a spell while I make certain all the connections are good; problem solved; mission accomplished.

Shut off the engine; crawl under the truck and put on a lot of zip-ties; put up all the tools; go in the house and wash hands before climbing in the truck to back it off the ramps.


I hop in the truck, hit the starter, and uh-oh, crank, crank, crank, no start.

What's wrong now ??


Investigated the fuel-solenoid --- no problem there; solenoid strongly jerks in the plunger and the terminal is HOT.


No problem with the filter.


I pumped the lever on the lift-pump several strokes; it felt healthy; hit the starter and still no go.


Try a squirt of ether several times; it hits on the ether and runs a lick or two, but no start.



I almost believe that I must have disturbed a big chunk of rust on the DRAW-line and it too is now leaking and sucking air.

It must have taken a bit for the fuel to drain out enough to suck air, as when I started it to test for leaks it was running before I could let off the key.

I done used up too much of my roll of fuel-line so replacing the DRAW-line will have to wait until tomorrow.

thrashingcows

Man just when you think you have the problem beat...it keeps coming back and "one upping" you.

BearKiller

I found a bit of discrepancy in what I was expecting to find when I removed the short rubber lines between the frame and bulk-head.

The lift-pump inlet line is 5/16 and the RETURN right at the engine is 1/4.


I was expecting to find the same back at the bulkhead.

Instead, the RETURN is 5/16 and the DRAW is 3/8.


The new all rubber RETURN is 3/8.

BearKiller

If everything went perfect, I would soon be dumb as a rock.


I had every intention of also replacing that rusty DRAW-line; I just didn't intend to do it until I had restocked my supply of new line and got a couple more boxes of clamps.

Now I get to go to the parts-house first thing in the morning.

Jklawinsky

While installing my airdog, I put a barbed connector that just snapped on to the original return on the bulkhead. For a couple bucks it was good insurance that my return line won't be leaking.

BearKiller

Another 30-foot of good GATES 3/8 hose in hand, plus whatever few feet was already here, I replaced the DRAW-line in it's entirety.

I swapped out the 5/16 street-el/hose-nipple on the lift-pump for likewise in size 3/8.

I routed from lift-pump inlet to the see-thru inline filter up next to the dormant grid-heater solenoids; then, from the inline filter, down the firewall to inside the frame-rail, through a cross-member brace, over another cross-member and immediately under a bed-member, then atop and alongside the tank to an ELL with a short leg that connects to the DRAW nipple on the bulk-head.

It requires about 12-feet of hose per run; two runs --- DRAW and RETURN means about 24-feet of hose should be sufficient to re-plumb a truck.

Now, both DRAW and RETURN are 3/8 GATES, with the exception of that little six-inch piece of 5/16 RETURN at the bulk-head and the short leg of 1/4 RETURN at the rear of the engine.




The brand-new fuel-lines and inline filter were completely empty and dry of fuel.

Working the lever on the diaphragm lift-pump about thirty strokes resulted in a healthy stream of fuel rushing through the see-thru filter.

Another thirty licks and it began to register fuel-pressure on the gauge.


A quick snort of ether and !!VAARRROOOOOOMMM!!!!, we're back in action.

Engine running, the antique diaphragm lift-pump is holding steady at 7-PSI.




The steel DRAW-lines must have been so rotten that I managed to knock a rust-chunk loose and all the fuel bled backwards, emptying the line.


I am just thankful that it didn't happen somewhere else; no better place for a fuel-line to fail than at home and already up on the ramps.

MARF75

Hey BK,not trying to rob your thread but,did you change the return from the tee at the back of the block?
I have just located the source of a new fuel leak on my 93.(Michigan rust!!) Cummins calls it a fuel drip line. It exits the IP towards the block then runs tight to the block under the intake manifold to the back where it ties into the tee with the return from the injectors.
When I upgraded to the 3/8 supply line I had the whole body off the truck and tryed seperating that tee at the back of the block on the return to no avail.
So now with the body back on with fresh paint and a $67 fuel line from Cummins, I am going to have to get at that blasted tee again

I was wondering if you had dug into this at all,if so,any advice?

Oh, I forgot to mention, I may have to remove the injector lines from the IP and they have a bad case of the Michigan cancer also.

BearKiller

MARF75,


NO; I didn't mess with anything --- YET --- above that 1/4" "tail" that connects into that TEE above the starter.


Other than maintaining original appearance and the fact that Cummins chose the neatest, most sensible, path for those two RETURNs, there is no reason whatsoever that one could not simply route those two lines separate and TEE them together wherever it was most convenient.

Those two little RETURN-lines could be rubber from their origin and accomplish their job just as well, maybe better.

The early Ford/I-H diesels used rubber just about all the way; even the little lines from injector-to-injector are rubber.


Rigid steel lines are initially cheaper than rubber for the manufacturer, plus they are more assembly-line friendly, meaning still more savings for them.

Other than the high-pressure injector lines, rubber is the better choice everywhere rigid steel was used, as rubber will absorb vibrations without developing cracks; and, the obvious, rubber will not rust.



I even suspect that there are braided stainless flexible lines available that could replace those rigid injector-lines.

You experts weigh in on that last bit, please.