Jinma 284, Y385T engine, zero oil pressure, bad pump?

[nepa]

After seeing zero oil pressure on the gauge, I just installed a new oil pressure sender to no avail. To do a double check, I took the new sender off and left it off while starting the engine and running for about 5 seconds. I hoped to see oil shooting out. Not a drop. Oil level is fine on the dipstick and I just changed it 2 hours ago. Trying to decipher the manual, it appears that the oil filter comes after the pressure sender so even if I had a bad filter the oil should have shot out with the sender off. I can not believe that I have a bad oil pump but I guess that the pump is the only thing left. Has anyone replaced the oil pump? How big a job is it? Does the drive shaft to the front diff need to be removed? Who has them to buy? Thanks.

 

[Bob Rooks]

Could be several different things, of which I have heard of before. 1) Broken pick up tube. 2) Broken pin in oil pump shaft drive gear. 3) Broken oil pump drive shaft. I think the pick up tube and screen come as an assembly from a dealer, the roll pin comes from any hardware or auto supply store, and the oil pump drive shaft comes as an oil pump assembly from a dealer. Affordable Tractor, Circle G Tractor, and many others would stock those parts. You will have to drop the sump, or the sump bottom, to determine the actual problem.

 

[quicksandfarmer]

An even more conclusive test is to take the oil filter off and spin the starter, if nothing comes out your oil pump isn't pumping.

I had my oil pump fail at about 500 hours. The drive shaft sheared off. How big a job it is depends on what kind of oil pan your engine has. On some Jinmas there is an access plate in the bottom of the oil pan, it's there so you can replace the oil pump easily. If you don't have that access it's a pretty big job, the oil pan is a key structural component of the tractor. It's attached to the transmission on the back and the front axle on the front. You have to split the tractor to get it apart from the transmission and hoist the engine slightly to get it free of the front axle. If you search the archives I have an epic thread giving step-by-step instructions for doing it. It's really more daunting than difficult. I ended up doing it twice (long story) and the second time it took me two hours to split the tractor and four hours to reassemble it, it's amazing what a difference it makes knowing what you're doing and having all of the tools at hand.

 

[nepa]

Thanks for the replies. It is amazing how many different versions of this engine there are. Even when you want an oil filter. Anyway, the oil pan on my engine appears to be a cast iron plate about an inch high, 12 inches front to rear, and the width of the block. It is held to the block with 20 bolts. It certainly looks like it is on the block only and not on the trans and will not require splitting the tractor or touching the front axle. The pan has about half inch clearance to the drive shaft to the front diff, so it appears that all I need to do is remove the 20 bolts and slip it to the side to get it out. I do not know how big the oil pump is and if I will be able to slip it by the drive shaft to pull the pump out. At worst, I pull out the drive shaft if there is no clearance.

I have read some prior posts that pose disagreement as to whether the oil filter is on the suction or pressure side of the oil pump. Does anyone have any knowledge on this? It seems that if a defective filter is on the suction side this could cause no oil to be pumped and no pressure. Any thoughts?

By the way, the tractor has only 416 hours and only 2 hrs since the last oil change.

 

[quicksandfarmer]

Oil filter is on the pressure side. The oil pump sits right above the sump and the pickup tube goes down into the sump.

There are at least three versions of the oil pan. Is yours stamped metal? Usually tractors have one that is cast iron. With the cast iron pan, in addition to the 20 bolts there are another four that connect the pan to the transmission, their heads are behind the clutch. To get to them you have to split the tractor.

 

[Bob Rooks]

I have read some prior posts that pose disagreement as to whether the oil filter is on the suction or pressure side of the oil pump. Does anyone have any knowledge on this? It seems that if a defective filter is on the suction side this could cause no oil to be pumped and no pressure. Any thoughts?

The engine oil filter is always on the pressure side of the pump. The suction side of the oil pump always has a screen that can sometimes become plugged from lack of maintenance.

 

[TTTTTT]

Hasn't been said yet. You can check this before you get into a big job. On my DF there is an adjustment screw on the oil filter bracket. i have adjusted my oil pressure at this point. Perhaps it has been closed off not letting or little oil through. i adjusted mine with the engine running while watching the pressure gauge. Just watch if you back it out too far it may pop out sending a bit of oil everywhere.

Good Luck Dave

 

[nepa]

As an update: I've taken the cast iron oil pan off. 20 bolts on from the pan to block was all - none into trans. It slipped off with the 4wd drive shaft in place but it looks like the shaft must come off to get the pump out. As a note to TTTTTT, I started the engine for 5 sec with both the filter removed and pressure sender off and not a drop of oil came out. I believe that a good indication that the pump moved no oil.

 

[quicksandfarmer]

The front driveshaft comes off pretty easily.

 

[nepa]

Update: I have not taken off the drive shaft yet and it appears that I may not need to. I removed the sump off the bottom of the pump and the impeller came right off with the sump. The shaft had broken right above the impeller. I see no reason for that to have happened. There was minimal debris on the sump screen and no debris to jam the impeller. So I am still not finished and have the following questions:
1) I still need to get the pump out and see nothing holding it in. What holds the pump into the block?
2) Since there is no obvious reason for the shaft to break, should the whole pump be replaced or just the shaft?
3) It appears that the drive shaft may not need to be removed. If it does, there is a trans support only half inch below the shaft. Can this support be removed without otherwise supporting the trans or taking special precautions?
Thanks.