Jinma 284 Hydraulic issues, Motor bogs down

[razed1022]

Hi all, I purchased my 284 new in 08. I have replaced the hydraulic pump once a few years ago. Trying to stop leak. Still leaked from same area. Seam around the pump and hose fitting that goes into pump from quick connect fitting. I put a rebuild kit on and was told that hose going into pump required a 18mm Hyd washer. I replaced everything and now it really leaks like a faucet. Looks like mostly coming from that hose to pump where I put washer. Also before I replaced anything the motor would start to bog down and die when I'd bring the bucket down or tilt bucket up only. Sometimes while driving it I'd hear a loud sound like you'd here when you turn your power steer to far one direction till wheel can't go any further. Not sure that explains the sound. That's when I decided to maybe address the leaking Hyd issue. For years I've just been adding fluid from dripping leak now its pouring. I tried contacting Tommy at affordable where I usually get my info/parts but haven't been able. "Holidays and all Probably".
Any help would be greatly appreciated guys!!
Thomas

 

[piper184]

Some of these used a washer with molded in rubber gasket and some used o-rings.
The part that the hose screws onto is actually an adapter that screws into the back of the pump. There will be a seal on both ends of that adapter, either washer or o-ring.
There are several places that could be leaking, wipe it all down with solvent and let it dry. A quick spray of brake cleaner is useful here.
Start the tractor and use a cloth or paper towel to monitor the connections to see if you can determine exactly which one is leaking.
Possibilities are 1) where the hose is crimped onto the threaded end. 2) the hose itself close enough to the end that it runs down onto the fitting. 3) the seal between the hose and adapter. 4) the seal between the adapter and the pump. 5) the pump housing itself. Maybe stripped threads or cracked housing.

The sound you hear when a cylinder hits end of stroke or encounters too much load is the pressure relief valve opening to dump extra pressure so as to not blow a hose or dead-head the pump. Bogging the engine down under full hydraulic load is normally an indication that you have reached the working limit of the hydraulic system.

Has this changed recently or has it always acted the way it is now, except for the leak of course?

My pressure hose blew out last winter and dumped the entire hydraulic fluid on the ground in less than 5 seconds. The hose was new with the 2006 tractor and had 900 hours on it. I was surprised it lasted that long. The hole was not visible from the outside of the hose but the fluid was pouring out all the way around the outer wrapping so I knew it was an internal failure and not an external puncture. Normal stuff, easy fix to replace the hose. Installed a new o-ring at the same time.

 

[razed1022]

No, the noise just started. Just strange that it makes it when lowering empty bucket but not while lifting. But then it does it while tilting up but not down. I have gotten that noise in the past when I try and lift to much or turn steering wheel to far to one direction. Even just driving it around to my garage in first it would periodically make that noise. I was thinking all the leaking hyd fluid was causing some sort it to make that noise. Waiting for snow to stop to go back out and check hose fitting for leak. So. Colorado here.
Thanks for the reply.

 

[piper184]

My loader also makes some strange noises that are not the relief valve. Usually while curling the bucket up and only when it is cold outside.Didn't make that noise when it was new and has been happening for several years. Since it only happens when the fluid is cold, I don't worry about it, but I do notice it. I have heard of hoses de-laminating internally and a "flap" of material can then cause a partial obstruction when the fluid flows one way but is perfectly clear when it flows the other. Kind of a flapper valve situation.

I know it is kind of hard to tell but does the noise come from out near the bucket or back near the valve?
Do you have the OEM valve or has it been replaced with an after-market one?

The OEM valves are not very precise so they may be leaking internally a little in certain positions.

Is the noise different if you just feather the valve to move the bucket slowly as opposed to going to the stop for fast movement?

The base end of the cylinder holds more fluid than the rod end, so when curling or lowering you are filling the small side (rod end) and emptying the base side. More fluid has to flow out of the cylinder through the valve and back to the tank than is being supplied through the valve to the rod end. Perhaps this difference in flow rate has something to do with the noise.

Another thing to check, is after you use the hydraulics a little while, look in the tank through the filler hole and see if there are bubbles in the fluid. If so, it could be sucking air somewhere between the tank and the pump.

Have you cleaned the screen or replaced the filter lately?