case/david brown 1390 air in fuel lines

I have a case 1390 that has started having a fuel issue. At first I noticed that while running it would idle up and down quite often. The issue then progressed to when I would shut the tractor down for the night and get up to run it the next day it would immediately crank up and then die like it ran out of diesel. I would bleed the lines going into the injectors and it would run fine but with the same odd idle.

I assumed that the fuel filters needed changing but after changing both filters this did nothing to resolve the issue. I tried cleaning the lines where they go into the injectors and make sure they were tight, but no change.

Now the tractor will run for a bit and then just die and you have to rebleed the lines again to get it going.

I replaced the fuel pump about a month ago because the old one went bad and I had diesel in my oil. I pulled the pump yesterday and took it apart and cleaned it, I did notice that it had some nasty water in the upper portion(the bowl?). The rubber diaphragm looks fine and when I hit the manual pump lever it all seems to work fine. I checked all the lines I can see and all seem to be tight but I am still having this issue of it dying and now it happens more frequently.

It seems like I am getting air into the fuel system from someplace, where should I check, and how can I check? A buddy suggested I hook up a air line to the start of the system and see where diesel blows out, I just haven't had a chance to do that yet. Also, could it be a issue with the fuel pump I bought? Has anyone ever had an issue like this before?

Does it do it if you keep the tank clear full, we had one many years back at our dealership that the suction pipe internal to the tank vibrated and cracked enough to allow air when the fuel level was below the suction pipe, this would be easy to check. If that is the issue you could fabricate a fitting to draw fuel from the tank drain. Just keep irt clear full for a day or two to check that out, good luck, you may want to also check all joints in the line from the tank to the pump to make sure that nothing is loose or a line possibly rubbed through.

(quoted from post at 08:55:35 04/28/20) Does it do it if you keep the tank clear full, we had one many years back at our dealership that the suction pipe internal to the tank vibrated and cracked enough to allow air when the fuel level was below the suction pipe, this would be easy to check. If that is the issue you could fabricate a fitting to draw fuel from the tank drain. Just keep irt clear full for a day or two to check that out, good luck, you may want to also check all joints in the line from the tank to the pump to make sure that nothing is loose or a line possibly rubbed through.

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Thank you Mel, thats interesting, I will try filling the tank completely and see what it does. I generally don't ever run it with a full tank of fuel as most times I fill it 5 gal at a time. the line that comes from the tank to the pump is a plastic line with metal fittings, all the other lines are metal so I am surprised that this one is not. I checked all the fittings and they are not loose but I didn't check the hose

I have a 1494 that did exactly the same
thing. Quite frustrating. Finally put a
12v fuel pump in the line and keyed it into
the switch so it engaged as soon as the key
was turned on. That fixed the problem.
Then RG Martin on here pointed out the real
problem is the little push rod that works
the fuel pump must be worn. Sure enough,
the ends were worn down enough the pump was
not being stroked enough. Easy to replace,
just take your fuel pump loose and put a
new "dowell" in place.

My 1210 DB sits out in the field and shames the CASE name . I
will remove the filter base and carefully reseal the new fuel
filters . Same deal as the Perkins motors on massey combine ..,
Real PIA getting it sealed right.in the DB 1210s defense ,.the
filters were full of water and the lift pump looked like it came
out of the bottom of a catfish pond. .Never did care for the
suction idea on the david brown BRITISH poor design.There are so
many possible failure points it makes me angry. . Compounded with
My frustration with a Jaguar my son got rid of 15 yrs ago that
still pizsme off to think about it. Really does seem reasonable
that the Brits could not designscchitthtosmell

Ever consider that it's Case shaming the David Brown name??? David Brown tractors, pre-Case buyout, are well regarded for being good, solid, reliable, and economical machines.

Ok, so I only had time yesterday evening to fill the tank to full. I bled the filters and lines again just to make sure I was starting with no air in it and fired her up. The tractor idled fine and I didn't notice a miss to it, I let it run for about 15 minutes and it never died. I wont get chance to really run it again until sunday prolly. If it continues to run fine until the tank runs low then I can imagine that it is a crack in the pick up tube like Mel suggested.

Tim, it's funny you mention that, an older fella was telling me last night that I should put a electric fuel pump on it because the cam lobe might be worn enough for the pump not to work. I saw the metal "dowell" you talked about. I'll see if it's a replacement part that case can get or do yall think I could just fabricate a replacement from a grade bolt?

My last tractor was a Ford and honestly I liked it and wouldn't have minded going back with Ford if I could have found a big enough one with a loader in my price range. This old DB has been a really good tractor, it runs great but it has it's own set of issues, I really hate the way the hood lifts, mines broken so I plan to redesign it to lift more like a corvette style

I had to bleed the lines again yesterday, but I ran it with that full tank of diesel and I never heard it idle up and down like it had been doing, also it never sputtered and never died. I'm going to see what happens after it sits a couple of days and if it will crank back up without bleeding the lines, also I will see what happens when the fuel level runs low.

If it is a crack in the tanks pick up tube then I shouldn't have to bleed the line when the tank is full, correct? If it was an issue with the manual fuel pump then it should have died on me and had the same high/low idle inconsistency as well regardless of tank fuel level, correct? Just making sure I am on the right track narrowing this down.

So just an update: Filling it to full did not fix the issue, it ran great for 3 or 4 hours at first and then started acting up again and barely made it back. I ended
up talking with some guys at the fire house about the issues I had, I mentioned taking the fuel line loose from the tank to try and size it and how no fuel came out
and my Chief said I probably had algae in my tank and that I should have had fuel pouring out and that I should try blowing out the pickup tube to see if the fuel
flowed. So I did and sure enough fuel started pouring out when I blew the line with compressed air. So I drained the tank and sure enough the bottom of the tank was
full of algae, I did note some rust through near the drain plug so I patched that. The plug was completely clogged at first. I pressure washed the inside of the tank
until I couldn't see any more sediment coming out, and then I put it all back together.

Tractor ran fairly well but I still thought I heard a miss some times. It sat a few days before I could run it again and ,once again, it fired right up and then
immediately died and the lines had to be bled. So when I get a couple more days off I plan to go back through it and see if I have trash in the lines, pump, or filters
causing me issues. If needed I may go with that electric fuel pump. I'll post if I solve it, if anyone has any better ideas or something I am missing let me know
please, this is a PITA.

I will add that this all started about the time I installed a bush hog on my FEL and I have been cleaning trails with it, so I do a lot of stopping and backing up. Not
sure if it's in any way related but at this point I figure it's worth mentioning