Jinma model 284
- Thread starter jb7919
- Start date
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Mark,
Finally had chance to work on this Jinma. Discovered diesel leaked into oil. That problem has been taken care of.
Hydraulic still leaks out of vent in fill plug. All fittings were tight, no leaks. This leak continues after removing seat and checking fitting of steel tube. Even removed plat to check screen in hydraulic tank. Screen was flat. When raising bucket or 3 point hitch it is very slow to raise and does so in a stutter type movement. Power steering is also difficult. When lowering bucket is when fluid leaks out of vent tube in fill plug.
I'm thinking air in the hydraulic lines or something wrong with the hydraulic pump.
Any thoughts?
Much appreciated.
Jimreg
Finally had chance to work on this Jinma. Discovered diesel leaked into oil. That problem has been taken care of.
Hydraulic still leaks out of vent in fill plug. All fittings were tight, no leaks. This leak continues after removing seat and checking fitting of steel tube. Even removed plat to check screen in hydraulic tank. Screen was flat. When raising bucket or 3 point hitch it is very slow to raise and does so in a stutter type movement. Power steering is also difficult. When lowering bucket is when fluid leaks out of vent tube in fill plug.
I'm thinking air in the hydraulic lines or something wrong with the hydraulic pump.
Any thoughts?
Much appreciated.
Jimreg
Greg,
Finally had chance to work on this Jinma. Discovered diesel leaked into oil. That problem has been taken care of.
Hydraulic still leaks out of vent in fill plug. All fittings were tight, no leaks. This leak continues after removing seat and checking fitting of steel tube. Even removed plat to check screen in hydraulic tank. Screen was flat. When raising bucket or 3 point hitch it is very slow to raise and does so in a stutter type movement. Power steering is also difficult. When lowering bucket is when fluid leaks out of vent tube in fill plug.
I'm thinking air in the hydraulic lines or something wrong with the hydraulic pump.
Any thoughts?
Finally had chance to work on this Jinma. Discovered diesel leaked into oil. That problem has been taken care of.
Hydraulic still leaks out of vent in fill plug. All fittings were tight, no leaks. This leak continues after removing seat and checking fitting of steel tube. Even removed plat to check screen in hydraulic tank. Screen was flat. When raising bucket or 3 point hitch it is very slow to raise and does so in a stutter type movement. Power steering is also difficult. When lowering bucket is when fluid leaks out of vent tube in fill plug.
I'm thinking air in the hydraulic lines or something wrong with the hydraulic pump.
Any thoughts?
SPIKER
Elite Member
Hey JB79:
Ok that Screen should NOT be flat they should be round or pleated. that is there to keep large debris from getting sucked into the pump. If it is flat then the pump is starving for fluid and sucking air in past the front seal or in from one of the pump o-rings. You will need to replace that suction screen (under the seat & under the tube plate) with a new one, they can be had from several places.
The next thing to make sure of is that the Hyd Fluid is not getting into engine thru the front seal of the hyd pump. If the pump was dead headed or someone put too much pressure onto hyd.s then that seal maybe damaged. If that is the culprit then you can replace that seal or the pump. they are not too bad of price 120 +/- or so bucks from states side supplier or go FedEX and buy one from china for 80 or 90.
You can also buy rebuild kits for these pumps for a 20 or 30 bucks which are really just the shaft seal and two formed rubber O-Rings that fit into the pump body. just be aware the pump can not be fully tightened down as it will bind up there needs to be a fraction of inch loose/slop between the plates and pump body.
Pump has 2 bolts that holds the body and end plates together and catty-corners are two longer bolts that bolt it to the tractor engine front drive gears. I rebuilt mine but didnt get it quite right and just put on a NEW pump. My brother Pressure Washed my tractor after he used it and the high pressure water stream went between body of pump and end plate cutting the seal... He figured the pump looked greasy so he sprayed it really well :/
You can also take some grease and put a little coating around the pump body (Aluminum part) and the steel ends on it (o-rings between the two) as a test to see if that stops the air sucking.
went & got some old picks post for ya,
FYI I think there were 2 types of pumps if I remember right, see pic above.
Mark
Ok that Screen should NOT be flat they should be round or pleated. that is there to keep large debris from getting sucked into the pump. If it is flat then the pump is starving for fluid and sucking air in past the front seal or in from one of the pump o-rings. You will need to replace that suction screen (under the seat & under the tube plate) with a new one, they can be had from several places.
The next thing to make sure of is that the Hyd Fluid is not getting into engine thru the front seal of the hyd pump. If the pump was dead headed or someone put too much pressure onto hyd.s then that seal maybe damaged. If that is the culprit then you can replace that seal or the pump. they are not too bad of price 120 +/- or so bucks from states side supplier or go FedEX and buy one from china for 80 or 90.
You can also buy rebuild kits for these pumps for a 20 or 30 bucks which are really just the shaft seal and two formed rubber O-Rings that fit into the pump body. just be aware the pump can not be fully tightened down as it will bind up there needs to be a fraction of inch loose/slop between the plates and pump body.
Pump has 2 bolts that holds the body and end plates together and catty-corners are two longer bolts that bolt it to the tractor engine front drive gears. I rebuilt mine but didnt get it quite right and just put on a NEW pump. My brother Pressure Washed my tractor after he used it and the high pressure water stream went between body of pump and end plate cutting the seal... He figured the pump looked greasy so he sprayed it really well :/
You can also take some grease and put a little coating around the pump body (Aluminum part) and the steel ends on it (o-rings between the two) as a test to see if that stops the air sucking.
went & got some old picks post for ya,
FYI I think there were 2 types of pumps if I remember right, see pic above.
Mark
greg_g
Super Member
- Joined
- Dec 18, 2003
- Messages
- 6,126
- Location
- Western Kentucky
- Tractor
- JD3720 Cab, 300X loader with 4-in-1 bucket
Only lower the hydraulics with the engine running, otherwise you end up with empty cylinders and an overfull sump. When you lower the bucket with the engine NOT running, fluid only flows TO the sump, obviously raising the level. When lowering the bucket WITH the engine running, an equal amount of fluid is pumped to the opposite side of the cylinder - thus keeping the sump at the normal level. And a healthy suction screen should look like this:
//greg//
Brad_Blazer
Veteran Member
One point that may not have been mentioned: If you are operating on a slope with the vent/fill plug on the downhill side it is common for the fluid to cover the inside of that opening and it will get pumped out of the vent when you operate the hydraulics. That is normal.
If your strainer is flattened there will not be enough screen area to allow proper flow to the pump and a starving pump will operate as you describe. If it flattened because it trapped a lot of debris you need to do a drain/refill of your system.
If your strainer is flattened there will not be enough screen area to allow proper flow to the pump and a starving pump will operate as you describe. If it flattened because it trapped a lot of debris you need to do a drain/refill of your system.
