Jinma Hydraulic Pump - Failures

   / Jinma Hydraulic Pump - Failures #1  

doxford jim

Veteran Member
Joined
Mar 29, 2007
Messages
1,007
Location
British Columbia, Canada
Tractor
1959 MF-65 sold, 2007 Jinma 554 diesel.
Hi Guys,

I just had a new high output E-320 hydraulic pump fail (2007 Jinma 554 tractor). It was installed just a few days ago and worked fine when installed.
Today I was using the tractor and the FEL to clear some snow - and, because of the new pump, I was being very careful with my FEL.
With no warning or noise the pump failed - the casing split along the length of the pump and oil just sprayed out the casing :mad::mad::mad:
The pump was checked by hand before it was installed and the pump drive shaft turned fine - needed to use a small 6" crescent across the splines as there was just a small resistance as expected. There is no strain on the pump casing as the inlet steel pipe pretty much floats to where it is bolted on. The upper discharge connection flange is connected to a hydraulic hose which is flexible.
I have no idea of why the casing cracked unless the new pump had a faulty casing. At no time have I touched the pressure relief valve - it is the same as when I got the tractor new. I will take the releif valve apart and see if anything is amiss. That is the only thing I can think of is a faulty pump casing - the old pump I replaced was the original and I changed the pumps as the shaft seal had gone and I had the spare new pump sitting in the workshop.
Looks like another new pump is to be ordered.

Anyone else have the same failure with their alum. body hydraulic pump ? Will post a picture tomorrow after I get some taken.

Jim
 
   / Jinma Hydraulic Pump - Failures #2  
Split pump housing screams overpressure... What was the hydraulic pressure running(relief pressure on all relief valves) on the new pump after the installation? This is a commonly missed step when shadetree troubleshooting or replacing a failed component. A hydraulic shop will always test pressures as they do not want to be liable for the followon parts and repair when the real cause of the failure kills a second pump.

What I am getting at is that pumps rarely just fail on their own. There is usually some other cause or contributing factor. A "T" fitting and a high pressure gauge installed into the pump outlet line are relatively inexpensive compared to the cost of a second pump... The information they provide is invaluable in troubleshooting the root cause of issues, and insuring that all the relief pressures are set within specifications...

If you have Quick connect fittings to the front end loader valve, it is a relatively simple matter to make up a pressure gauge installation using a set of quick connects, a high pressure T fitting and a 0-5000 PSI gauge. Or with the right type of T, one of the QC connections can be removed from the hose end, the T and gauge connected and the QC fitting re-installed onto the T fitting. Install this in the line running from pump to FEL and confirm peak pressures are within limits when operating ALL the valves in the system(FEL, 3PH, ECT)...

Good luck with your next pump.
 
   / Jinma Hydraulic Pump - Failures #3  
One of the most commonly reported causes of pumps blowing up like that is faulty quick connects on the loader lines. If one isn't connected properly or if the check ball gets jammed, the pump will deadhead and blow up.
 
   / Jinma Hydraulic Pump - Failures
  • Thread Starter
#4  
Thanks guys for the comments.
This was totally unexpected and I was stumped as to the cause. I emailed Tommy at Affordable and was told that the two main causes are quick disconnect and the FEL controls. So this morning I will have a good look at it - after I have cleared up the oil from the shop floor.Kitty litter used as an absorbent and usually works well.
Not having worked on the Jinma disconnects, what is involved with removing the centres so I won't have a future problem with the balls ?
I will also get into the FEL control valve to see what may have happened - seized or broken valves, disconnected returns springs etc.
Any other thoughts on cause ?
Fortunately I had both the loader and the TPH in the raised position (snowblower on the back) and was able to drive down to the workshop spewing hydraulic oil en route ( will stop the grass rusting).
It is a real pain as I took real care installing the pump only to have this happen. I had no idea that I might have a problem with "dead heading" though have read about it over the years.
Thx
Jim
 
   / Jinma Hydraulic Pump - Failures #5  
I installed a Prince relief valve and pressure gage right at the pump outlet and it returns to sump. It protects the entire system.
 
   / Jinma Hydraulic Pump - Failures
  • Thread Starter
#7  
Well, I have just got back from the shop after checking over the FEL control valve - all looked good. I also looked at the pump I removed (E-314), the original pump that came with the tractor. This pump was leaking a little oil and as I had the new E-320 sitting on a shelf, thought I would put the new pump in and see what difference it made. It worked fine for a couple of days and then without warning, the casing failed.
Since the FEL control valve looked and operated good, that pretty much leaves the "quick disconnects" as being the culprit. The FEL and the TPH were working just fine just prior to the failure.
While in the shop I looked at the old pump that I took off, to see where the oil leak was coming from. The casing is good with no cracks evident. I checked the four nuts on the end of the pump, that clamp the parts together, and found two nuts finger tight and the other two just a little tighter. So it now looks like the oil leak was due to the slack nuts not clamping properly. I turned the drive shaft with a small crescent and found that it turned with about the right amount of resistance and was not binding at all. It looks very much like I might be able to put the old pump back and get up and running again.
There is still the problem with the new pump casing failing and I suspect the cause being the quick disconnects.
Any other thoughts would be appreciated.
Will look at the quick disconnects tomorrow.

Thx
Jim
 
   / Jinma Hydraulic Pump - Failures #8  
Jim,

Based on recommendations, I replaced my QDs with ones from Ronald at RanchHand Supply. Much better quality and no failure reports.

You an replace them, remove the check balls from them or remove them altogether and hard plumb the FEL if you don't pan on removing it much. Any one of those solution will work, I would think.
 
   / Jinma Hydraulic Pump - Failures #9  
Thanks guys for the comments.
Not having worked on the Jinma disconnects, what is involved with removing the centres so I won't have a future problem with the balls ?
Jim

Unscrew the QC from the end of the hose. Up in where the hose threaded into the QC, you will find a circlip that holds a star shaped plate in place. Remove the circlip, the starplate will come out, as will a spring and the check ball located behind it. You must repeat this process 3 more times, untill both tractor end QC's, and both FEL QC fittings have the balls removed. Also if you plan on connecting anything else up to the QC fittings, the balls will have to be removed from those fittings also. The balls push against each other when conected, so if you conect a fitting that still has a ball to one that does not, there will be no accompanying ball to push it open. This will result in an instant deadhead when the engine gets started...

Another good practice when dealing with QC's is to put a large ty-wrap/ziptie onto the female fitting behind the sliding collar. This will prevent the collar from inadvertently being retracted and relasing the QC.

You can inspect all the components untill you are blue in the face, but unless you put a pressure gauge in there to confirm what the reliefs are set at, you will not know for sure that you have found what blew up the new pump...
 
   / Jinma Hydraulic Pump - Failures #10  
One of the most commonly reported causes of pumps blowing up like that is faulty quick connects on the loader lines. If one isn't connected properly or if the check ball gets jammed, the pump will deadhead and blow up.

Spot on Rich - we've had it happen a few times on customers tractors. Often the Yangcheng factory change their quick coupling types from ball to pin, then back to ball again! This means that the quickies on the loader will fit the pump, but may not let the full flow though causing the pump to overheat and crack. We only found out a few years ago when fitting a fel to a customers brand new 254E tractor - we started it up and started the checks, but as soon as we lifted the revs the pump cracked. On close inspection the quickies on the pump were the pin type, but the loader had ball type fittings - you can't tell without actually looking down into the fitting as they are identical from the "outside".

Another time we had a customer who's pressure relief bypass valve on the fel failed. Because the Jinma loaders are generally in series (ie: the oil has to pass through them from the pump before servicing the back of the tractor) it overheated and cracked...

Jinma (or Siromer as we sell) are excellent tractors - but you do need to keep a close eye on detail and do regular checks to ensure everything is as should be... :thumbsup:
 
 
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