Air and diesel don't mix...

Hi there,
I have my David Brown 25D clutch all back together, and it works well! Problem is I had to introduce air into the lines, and I should be able to just bleed it out, right? But I have spent ages and ages bleeding the lines and breathers, I can get it running well and it will go for an hour or so, then it will just die. I have had this happen about 4 times! No blockages that I can see, but when I bought it, the lift pump was seized, I freed it up, but now it is leaking out the top of the pump. The lift pump is mounted on injecter pump, and is the plunger type. Not like the Sphinx pump on the DB 850.
This is driving me crazy!
Any help appreciated!
Thanks!
Joshua
 
I'm not a mechanic, so DON'T assume so.

If the pump is leaking oil, stands to reason that it could also be drawing in air. Does oil leak only when engine running, or leaks all the time?

...Now we wait for someone who actually "knows" what they're talking about. *lol*
 
if it runs for an hour it's not from not being bled, you have air coming in from somewhere. the leaky pump would be a good place to start.
 
When I was a kid growing up on a dairy farm in the 50-60's, the only thing I know about a diesel is dad would kick our ASK if we ran it out of fuel. I never asked why and I never got my ask kicked.
 
Things I'd check 1)Look for a restriction in the fuel tank 2)Make sure the fuel tank is vented 3)the lift pump is going bad and needs to be replaced.
Also do you have you have the fuel tank at least 1/2 full?
 

I agree with KCM. It sounds like it is sucking air. I have had this happen on a Ford with connectors with a rubber washer. I went over all of them and snugged them up and it was good after that. You may have an end that is bad. I would take them apart and remove and check them.
 
(quoted from post at 03:51:47 12/06/18) Hi there,
I have my David Brown 25D clutch all back together, and it works well! Problem is I had to introduce air into the lines, and I should be able to just bleed it out, right? But I have spent ages and ages bleeding the lines and breathers, I can get it running well and it will go for an hour or so, then it will just die. I have had this happen about 4 times! No blockages that I can see, but when I bought it, the lift pump was seized, I freed it up, but now it is leaking out the top of the pump. The lift pump is mounted on injecter pump, and is the plunger type. Not like the Sphinx pump on the DB 850.
This is driving me crazy!
Any help appreciated!
Thanks!
Joshua

If it is running for an hour before it starts having problems the first thing I would be looking at is the tank vent.

Also have a second look at any fuel lines you disconnected when you split the tractor.

After it dies what do you have to do to get it going again?

How does it start after it has sat for a few days?

Did this problem exist before you did the split?

The last thing that was worked on should always be your starting point when looking for a new problem that suddenly appears.
 
I would replace the lift pump. If it is leaking out that means it could be sucking air in. I have seen that problem many times on generators.
 
The tank seems to be vented, and I have tightened up all the lines. Once it dies, I have to pump for ages and ages and wind the engine over.
It has a decompression lever so there is reduced wear on the starter, If it sits for a few days, it will start instantly, then once the 'hour' is up it will die.
Before I did the clutch there were next to zero revs, a banjo was plugged, but I cleared that. Lift pump was seized, so was not leaking.
FYI, I didn't split the tractor, being a David Brown I worked on it out of the top.
Thanks!
Joshua
 
Start with the pump replacement as if it can leak it can suck air . Then check lines for air leaks like loose or maybe one got bent just a bit working on the clutch as you leaned in over the top.
 

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