jima backhoe hydro problem

[intheground]

hi guys, I have a jima lw-6 backhoe on a jima 284 tractor. while using it today after about 1/2 hour of use the bh seemed to lack the power it normally has and the hydros slowed down. after about an hour it had no power and the hydro just about worked. checked the fluid and it was very hot and airated. drained and change all the fluid, cleaned the filter thinking there might have been water in the hydro fluid because of all the rain we have had. went back to work and it was fine problem solved right.. wrong, after about a 1/2 hour same thing. fluid very hot foamy and the hydro just about worked. check for leaks could not find any thinking it was sucking air somewhere but all looked fine. using the pto and that itself is very very hot. could it be that it is cloged up and not putting out enough fluid? I don't know much about hydraulics so could really use some direction.
thanking you guys in advance..

 

[kennyd]

Possible one of the relief valves is sticking, causing the fluid to overheat. Is it making a loud squealing noise?

If the fluid is foamy, then there is a leak on the return/suction side of the system-hard to find because you will not see any external leaks.

This is a separate system from the tractor? You are using a PTO powered pump? Is there a filter? they are often the cause of leaks.

 

[intheground]

no loud squealing, but can here a straining sound in the pump when I engage bh. fliud is foamy and yes i'm using the pto pump there is a filter inside the tank which I checked and cleaned today when I changed the fluid.

Possible one of the relief valves is sticking, causing the fluid to overheat. Is it making a loud squealing noise?

If the fluid is foamy, then there is a leak on the return/suction side of the system-hard to find because you will not see any external leaks.

This is a separate system from the tractor? You are using a PTO powered pump? Is there a filter? they are often the cause of leaks.

 

[kennyd]

no loud squealing, but can here a straining sound in the pump when I engage bh. fliud is foamy and yes i'm using the pto pump there is a filter inside the tank which I checked and cleaned today when I changed the fluid.

Sounds definitely like a return side leak...

 

[intheground]

will change the gasket on the filter and the o ring on the return side hose tomorrow is thier any other place it could be?

Sounds definitely like a return side leak...

 

[AKKAMAAN]

I put a penny on the suction line/side... is there a suction strainer in the tank?

Edit
You are right Kenny, suction side dont show oil leaks.....still worth a check up, since oil shows foam/air....and how about shaft seal on pump?

 

[20 20]

Had the jw3 did the exact same thing ended up being a bad seal in the adjustment valve. Took more time to find it then replace, tiny little bugger tucked up inside.

 

[Ranch_Hand_Supp]

I have seen / found some problems with / in the pressure relief assy.


Ronald
Ranch Hand Supply

 

[RonMar]

I vote for the over pressure scenario also. Pressure = heat. Get a metric to NPT(18X1.5MM to 1/4NPT I believe) adapter and a gauge. Remove the metric to ORFS adapter on one of hte working ports and screw this assembly into that port to see what pressure it is actually releiving at... Lot of guessing and unknowns untill you actually know what all the variables are.

That pump should be as quiet as the pump up on the front of the tractor. I have this same backhoe, and the pump was noisy since new. The fluid returning to the resovoir does so thru the center of a banjo bolt on the left side of the tank. The center of that bolt is about 1/4" in diameter so the fluid returns as a high velocity straight stream. This shooting into the fluid in the resovoir injects bubbles into it and this whole areated mess rolls down past the intake strainer. I redid my return line so the fluid enters the tank slower and now my pump dosn't make a sound...

 

[AKKAMAAN]

Of course pressure creates heat when there is air in the oil....compressing air creates heat!! and then the hot air heats up the oil....but how would air get into a pressureized line??? It must come from a line with pressure lower than atmospheric pressure...the suction line!!!

I still bet on the suction side for the air problem......and I agree about the pressurized side for the heat problem....