Piper184

In order to pin point a leak you have to first get the area clean and dry. A pressure washer is good for this but if you don’t have one some spray foam engine cleaner and a garden hose will work.  For smaller areas some mineral spirits on a rag will work too. Brake cleaner will work but it expensive and will take off the paint.

Once clean and dry you can operate the tractor and check the area every few minutes to see if you can find the leak. As a last resort you can get a fluorescent additive for the hydraulic fluid and then use a black light (UV) to see the trace.

You are probably correct about it leaking at the 3 point rocker shafts. There are seals in there but they are not very tight. The rocker shaft goes through the upper portion of the hydraulic tank and if you overfill the tank it will leak out at the rocker shaft.

Even a tank with the fluid at the proper level can flood that shaft if you are working with the front of the tractor higher than the back. I have this issue every winter when I am pushing snow piles up high.

The other thing that can cause the tank to “overfill” is if you have air getting into the hydraulic fluid. It will foam up and push out of the vent tube. To check this run your tractor for a while and then pull the fill plug and look inside with a flashlight.

These tractors are dead simple in design and easy to work on if you have a good parts diagram to follow. Some of the factory diagrams take some close study to understand how everything fits together.

There are several documents you can download on my website under the Jinma link on the home page. http://www.harnerfarm.net

Pictures are always helpful even for your own records for future use.

I had a huge leak show up in the middle of moving snow last winter. After 14 years a bolt on the 3 point control valve decided to come loose and it blew the gasket out. I would suggest taking some wrenches and make sure all the bolts in the area are good and snug. It is always a good idea to go over these tractors every now and again and check all the bolts that you can get to with a wrench. The Chinese lock washers are not the best and they do work loose. Wheels especially but loader frames are a close second.

If you have a schematic and either a multi-meter or a battery and a test light it should be easy enough to test the switch either in the machine or on the bench.

It is also possible without a schematic but is a little more work.

Without knowing your electrical skill level it is hard to know how basic of a description you need.

First advice is to take a picture of the wires before you disconnect them. IF that is not possible, be sure and label them well so you can get them back where they belong.

A lot of people have upgraded to a Ford key switch which has better contacts and can take the load of the glow plugs better than the factory switch.

All of the wiring on these machines is barely adequate to function properly when new. As they age most of the spade connectors corrode and become loose. Both the crimp on the wire and the crimp that holds the female end onto the spade. This causes intermittent connectivity that manifests itself as all kinds of different issues.

If you follow the power from the battery to the switch it probably goes from the battery to a terminal on the starter, then to the amp meter then to the switch. Then the switch contacts will in turn energize the run, start and glow plug circuits. Fortunately these are done only one at a time so checking for continuity is straight forward.

You probably have a switch with the following positions from left to right.

Start – Off – Run – Start – Heat (glow plugs)

The start and heat positions are spring loaded and will not stay in those positions unless you hold it.

The run sends power out to the fuse box to power all the other accessories.

Either start will send power to the starter solenoid, probably through the same wire spliced together close to the switch.

Heat will go to the glow plug bus bar through the fuse in the fuse box.

What symptom(s) are you having that cause you to suspect the key switch is the issue?

Hope this helps and ask any questions you still have. Post pictures if you can.

Did you find a part number for it or is it not serviced separately?

If you have a part number, web searches should turn up something.

If it is not serviced separately you may have to buy a whole pump to get it.

However, you could:

Take it apart to see if it something that can be repaired.

Check with a local diesel shop that does pump rebuilds. They sometimes have access to repair parts that are not available to the general public. They also may have that part from a scraped pump or be able to find one that will work.

Look for a used pump such on on eBay. You may be able to find one for sale as a parts pump.

These tractors have really simple wiring. The only thing that I can think of that might get a little confusing is the alternator/regulator circuit. Relays can be a little confusing depending on how they are actuated, but they all work the same way.

Do you have a schematic?

Do you know how to test voltage and continuity?

You said you can’t read a schematic but these simple systems are the perfect place to learn. I would suggest doing a web search for “simple dc circuits” or some such. I would bet you will find all kinds of classroom style videos online.

You might also check a local trade school that might have some continuing education classes or adult classes at night. Also, another way to go might be a local high school, if you can find one that still teaches vocational ed classes.

If all else fails, a library should have plenty of good books on automotive wiring or how to read a schematic. Ask at the reference desk, they will help you.

I wouldn’t hesitate to tackle a complete re-wire of a Jinma and have threatened to do my own someday when I have the time. Already bought a new fuse block (not OEM crap) to do it right. My know how in wiring is all self taught. Just think of it as running a garden hose. The positive side of the battery is the faucet and the negative is the drain. The trick is to make all the water go where you want it, when you want it and to make sure it all goes down the drain with no leaks.

It is a little more complex than that, but not much, and it is a good way to get your head wrapped around following the traces in the schematic.

Best of luck and please ask questions. I may have a schematic for your tractor, or one close to it if you don’t have one.

Probably the only test you can do with the injectors still in the engine is have it running and then crack open each hard line, one at a time. When the line leaks enough to stop the injector output you should be able to detect a definite change in engine sound and RPM.

You test each injector one at a time. If you don’t get a change on any one injector it would indicate that injector is not working anyway. Think of it like pulling spark plug wires on a gas engine that is missing. If you pull the wire from the bad plug, it doesn’t change anything.

This test will only tell you if you have a nearly or completely failed injector and won’t tell you anything about actual operating condition of any of them.

For a complete test of pop off pressure, spray pattern or dripping/leaking, you need to remove them and have them tested in a shop equipped to do so. For some people it is easier and/or more cost effective to just replace the injectors with new ones.

With that in mind, you could buy one new injector and put it in the front cylinder, start the engine and see if it runs different then before. If not, then the one you took out is probably OK, move it to the middle cylinder and try again. Then do the same to the back cylinder if the middle one is OK. Hopefully that will find your bad one.

Kind of like finding the bad bulb in the old fashioned screw in type Christmas tree lights.  🙂