JD 1140 oil pipe problem

[shaughnessy]

Hi I have an old european specification JD1140 tractor, which started leaking hydraulic oil. I traced the leak to a broken black plastic pipe which came off an elbow at the bottom the of high-pressure oil pump and runs up to a fitting on top of the oild reservoir which is mounted between the radiator and the fuel tank. I've also found another black plastic pipe, which runs from the same fitting on top of the reservoir and heads in the direction of the back of the tractor under the cab, which is also broken. Does anyone know what these pipe are for, and where the second pipe is meant to end-up? The pipes are quite slim (I would say their internal diameter is about a quarter of an inch), and they are just a push fit (no clamps) so I assume they don't operate under pressure. I can't work-out their role, so any advice would me much appreciated.

Kind regards

Denis

 

[jd110]

Welcome to the forum!
The plastic tube from the pump to the reservoir is a "leak-off" line. There are two seals in the pump. Any oil that gets past the primary seal leaks out through that tube and into the reservoir. That saves the outer seal from holding too much pressure. The other tube that runs back under the cab is a breather tube. It is connected to the "shift cover" under the cab. When the main hydraulic pump demands oil form the small reservoir, the second tube allows air to be drawn into the reservoir so a vacuum is not formed. You are correct, there should be no pressure in that line unless the seal in the pump is going bad and excess oil is getting past the seal. I assume you should have a square access panel in the hump in the floorboard. If you remove that panel, you can access the shift cover to replace the tube.

 

[shaughnessy]

Dear JD110, thank you for such a prompt and informative reply- I really appreciate it. The leak from the elbow under the pump was a steady drip every two seconds or so. In your opinion does that suggest that the seal in the pump is in really bad shape, or is such a volume of leaking oil acceptable?

I've had my 1140 for a few years now, and I'm always amazed at how well it starts- even when it has been unused for a few months it fires at the first turn of the switch. Its weakness is the hydraulics, which become juddery and inconsistent when the oil is hot and the engine is idling, to the extent that it will lose power steering intermittently when creeping along at low revs. Someone has suggested that I might simply try replacing the hydraulic fluid, as it might be contaminated with moisture leading to compressibility when hot. Does that make any sense?

Kind regards

Denis