m7040 busted hydraulic hose

[m7040]

yesterday wile digging ot an old gas tank on the farm I busted a hydraulic hose for the FEL curl function. Lots of oil spray before I could shut it off.
Is that one of the hazards that needs to be cautioned against?
Think that slamming into the dirt with the bucket tilted caused too much pressure in the line and ruptured the hose.

 

[MadReferee]

Quite possibly. When you replace the hose make sure the new one is at least a 2-wire hose rated for 4000 psi or greater.

 

[wushaw]

It won't be your last, wear saftey glasses unless you have a cab.
I got sprayed three times with my previous tractor and all three times I had to wipe hydraulic oil off my saftey glasses.

 

[N80]

I understand that pushing with the bucket in the down position puts tremendous pressure on the hydraulic system. I'm wondering (since I only have a cursory knowledge of hydraulics) why the pressure release valve didn't prevent this?

 

[MadReferee]

I understand that pushing with the bucket in the down position puts tremendous pressure on the hydraulic system. I'm wondering (since I only have a cursory knowledge of hydraulics) why the pressure release valve didn't prevent this?

Because there is no pressure relief on the work ports. When the spool is in the neutral position you have a mini-circuit between the spool's two work ports and the cylinder. Since fluid is blocked from exhausting when in neutral, something has to give. It's usually the hose but sometimes the valve actually cracks or splits open. A rather dangerous situation.

On most heavy equipment there is a relief on each work port, or at least those that have the potential for problems like the bucket curl. My dozer has reliefs on the bucket curl work port, the clam open and the clam close. But then again the breakout force on most dozers is pretty high, mine is 18,500 lbs.

 

[m7040]

Thanks for the advice. I have a cab so it was safe but lots of oil all over. Dealer replaced the hose this morning on warranty so I am ready to install it. Think one needs to be careful with the curl function and keep it fairly level when applying force with 4 wheel drive. Seems it will break the hose if not. On my two wheel drive MF 203 loader it has not been a problem because I think the traction is more limited.

 

[SkyPup]

Using four wheel drive to push the bucket into the ground below a level angle will certainly result in blown hydraulic lines or a messed up FEL linkage. Often the rigid metal hydraulic pipes burst before the flexible rubber hoses go too. If you want to try to prevent or lessen the chance of this happening, use only two wheel drive.

I installed a hydraulic pressure gauge (0-5,000 psi) onto my L-3130 LA723 FEL control linkage adjacent to the dashboard so that I can see the hydraulic pressure all the time with a quick glance.

 

[wushaw]

Thanks for the advice. I have a cab so it was safe but lots of oil all over. Dealer replaced the hose this morning on warranty so I am ready to install it. Think one needs to be careful with the curl function and keep it fairly level when applying force with 4 wheel drive. Seems it will break the hose if not. On my two wheel drive MF 203 loader it has not been a problem because I think the traction is more limited.

You must have a real good relationship with your dealer since hoses are not covered under warranty

 

[m7040]

I did not know that hoses are not covered.

 

[rdsaustintx]

You must have a real good relationship with your dealer since hoses are not covered under warranty

Mine was. Broke one on the FEL and dealer fixed it on-site.

Russell in Texas