JM284 Pump Destructon

[SMEI]

I recently built a crated JM284LE with a ZL20 FEL. Everything went well - I evan gave it a drive around before putting the FEL into place and snapping it all into the quick snap fittings.

This is when the problems started!! After few minutes of running and a raise and lower of the FEL - "CRACK" the hydraulic pump split open and oil everywhere and the motor stalled /forums/images/graemlins/shocked.gif

Not being one for hydraulics /forums/images/graemlins/smirk.gif I quickly installed another new pump - "CRUNCH" the hole thing split and destructed again /forums/images/graemlins/mad.gif and this time I did not evan raise or lower the FEL - only turned the power steering??.

On further investigation I have discovered that the "male" quick connect on the FEL line has some pitting and damage around it, was more difficult than the others and seemed ? loose when snapped together- it also seems to be older that the rest as it was installed with thread sealant tape??

My question: /forums/images/graemlins/grin.gif Was it possibe that this fitting caused the snap coupling to not work properly - hence a build up of pressure in the pump and no immediate safety valve between pump and FEL to avoid the destruction of the pump??

Any advice please - As I am rather nervous about installing another pump and going for it again??? <font color="blue"> </font> bradsan@bigpond.com.au

 

[DIYGuy]

This is well documented user error in many of the chinese forums with Jinma tractors. If the connection to pump is not properly plumbed, the pump will self destruct almost instantaneously.

Most of us actually wrap a zip tie around the quick connects so that even an accidental disconnect can not occur.

There is a blockage somwhere in your plumbing. There are several options for Jinma hydro-routing, so without pics this is tough. If you post the pics in the chinese tractor forum, you should get some answers.

A net search of other forums will also yield a wealth of information on this topic.

 

[Ranch_Hand_Supp]

SMEI, Sounds like the hyd pump dead headed.... {hyd pump pumping and no place for the hyd oil to go}

Sounds like you may have a problem with one of the quick disconnects..... I would replace it.

Ronald
Ranch Hand Supply

 

[Soundguy]

</font><font color="blue" class="small">( Was it possibe that this fitting caused the snap coupling to not work properly - hence a build up of pressure in the pump and )</font>

Yep.. unfortunately you were a tad hasty to simply change parts rather than find out what caused the aprt to fail. Deadheaded pumps due tend to catastrophically die... and QD's are a prime cause for that.

I believe the qd's onthe chinese setups.. with no relief before the qd, is a 'poor' design at best...(in my opinion, as it invites failure)... or perhaps a better description is 'brittle'.. as it does work as intended, as long as everything is perfect.......... I won't call it a 'fault', as this is an economy designed tractor with money saving features in mind.. and a relief up there would cost more in fittings.. etc..

Soundguy

 

[777777]

Hi Soundguy,

Being a nonhydraulic guy myself, I was wondering if you can install a relief valve in the system.
If yes, where and how would you go about it ? Please keep it mind it would be a hydraulics for Dummies issue. Any idea of the relative cost ?

Thanks
Tom

 

[Soundguy]

There already is a relief in the system.. it's just that it is downstream of the 'break' point where the qd coupler is. It would be notheing but money and time to install a relief after the pump, before the qd.. a couple short hoses, and the relief itself, as well as a longer hose to return to sump.. might even do away with one stubby hose and just make the qd attatch to the relief itself.

I've no idea of the exact price.. but would figure in the neighborhood of a couple hundred for the relief and hoses and ends.. plus a little sweat equity to install it, and top off with fluid. Next time qd poped open.. relief would go into bypass and dump oil to resevoir. This will load system down a bit.. but you would notice the absence of hyds.. and without the expensive self destructing pump.. etc..

Soundguy

 

[777777]

Thanks Soundguy,

Think I know what you are saying and am trying to picture it.

We have a place here that selfs a lot of valves and will custom make hoses any size you like at a good price so it an interesting thought.

Thanks again

Tom

 

[SMEI]

/forums/images/graemlins/confused.gif OK, now I really need some advise and help. I have replaced the QD's and installed a new pump.

I also replaced the diverter valve and the 3PT valve.

As far as I can see there are no leaks and all pipes, hoses and fittings seem OK.

I ran the unit with its FEL disconnected from the system. The 3PT raised and lowered OK and the steering went from lock to lock without stalling the engine /forums/images/graemlins/grin.gif This test was conducted at 600rpm idle speed.

I then reintroduced the FEL to the circuit and ensured the QD was OK. Again at idle I checked in order:
1) raise & lower 3pt hitch
2) steering from lock to lock.

I then raised the FEL a few inches up to clear the ground.

I then increased the rpm and went to reverse out of shed and CRACK the pump let go again.

I feel the problem is in the FEL control mechanism, what can I do?? I got only one pump spare??? /forums/images/graemlins/blush.gif How and where do I start to fault find the system? Does anyone have access to a good diagram of the chinese ZL20 FEL hyd system??

 

[Wayne_Freeman]

Call this guy(Tommy) and he can help you troubleshoot and he has most parts in stock! http://www.affordabletractorsalesco.com/

 

[Egon]

The hydraulic fittings on the FEL block are not installed properly.

Egon