JD 401 hydraulic problem

[Tx Jim]

1st thing blow air through fuel return line from inj pump to tank. It's also possible return line fitting is plugged.

 

[southwind26]

1st thing blow air through fuel return line from inj pump to tank. It's also possible return line fitting is plugged.

Blew the return line from inj pump out with air, it was clear, fitting was clear. Ran the tractor and fuel coming out is just a fast drip. Is this a sign the inj pump is going out?

 

[Tx Jim]

Can you get a gauge and test fuel pressure leaving lift pump?

 

[jd110]

No one has mentioned the possibility of a misfire. Does the engine seem to run as smooth at idle as it used to? Try loosening one line at a time at the fuel injectors and listen to how the engine sounds. If you loosen one that does not make a difference in how the engine runs, then that cylinder is misfiring. If so, then the problem could be a bad injector, a bent pushrod, broken rocker arm, etc.

 

[southwind26]

No one has mentioned the possibility of a misfire. Does the engine seem to run as smooth at idle as it used to? Try loosening one line at a time at the fuel injectors and listen to how the engine sounds. If you loosen one that does not make a difference in how the engine runs, then that cylinder is misfiring. If so, then the problem could be a bad injector, a bent pushrod, broken rocker arm, etc.

Thanks for the input jd110, the engine fires right up less than a quarter turn as always, runs smooth thru several rpm ranges. If I move the loader is will stall, if I just let the engine idle it will stall in about 2 mins.... If I loosen the injector lines one at a time, wouldn't it spray fuel everywhere or do I loosen just enough so a little fuel leaks and see if I can hear a difference?

 

[southwind26]

Can you get a gauge and test fuel pressure leaving lift pump?

I ordered a schrader valve and a gauge today, I should be able to test Tuesday

 

[jd110]

WHen you loosen the lines, some fuel will spray out, but not a large amount. It will be under high pressure, so be sure to keep your hands out of the way of the spraying fuel. Injection into the skin is very dangerous. After rereading your post stating that engine will also stall when idling after 2 minutes, that sounds more like return line plugged. DId you remove the return fitting that screws into the top of the pump? It should have a check ball in it. It is a pretty common problem for this check valve to be clogged and restrict return flow. The timing window is on the side of the pump. A small rectangular plate attached with two screws. Place a bucket under the pump and loosen the two timing window screws a cople of turns and then pry the window loose to break the seal. Start the tractor and let the fuel leak from the window. See if it still stalls when moving hydraulics or if it continues to run longer than 2 minutes.

 

[southwind26]

To check stand-by pressure one needs a 3000-5000 # gauge with the correct hyd fitting to attach to hyd pressure port. Here's the spec's for the pump plug(parts key 5) if your tractor has the smaller pump
Specification
Weight: 0.18 LBS 0.08 Kg
Thread Size 0.750 IN
TPI (Threads Per Inch) 16
Thread Length 0.438 IN
Length 0.750 IN
Diameter 0.465 IN
Hex Size 0.875 IN

This picture shows the left side of the front hydro pump. I if I remove that 1/2 bolt from the top is this where I will put my new hydro gauge? I was worried that this was some type of a adjustment bolt for the pump. I removed the 1 1/4" plug from the other side of this bolt but those threads were very coarse threads not npt

 

[Tx Jim]

Before attempting to check hyd pressure be sure to check fuel return line fitting that attaches to inj pump for blockage. Port to check pressure is plug(parts key 26). The following spec's should get you an adapter.

 

[buickanddeere]

Hey I've got a 300b Deere backhoe it has the electric wire that goes to hydraulic pump it makes the releases the pump pressure that might could be your problem

How does that make a difference once the starter is disengaged and the engine is running ?