Any damage when you try to lift too much?

[hz293]

I have a Kubota B7510HST and have a question about trying to lift when the load is more than the FEL or 3ph will lift. Is there a bleed off valve? If there is when it operates, does it lose hydraulic fluid? Can someone tell me how the system works?

Harris

 

[RobJ]

Yes there is and no it should not.

Basically a check ball with a spring on it. When the pressure overcomes the spring pressure, fluid will bypass the ball and go into the return line or resovior. So you do not lose any fluid. Sometimes you will hear a buzzing sound when the system bypasses. this is the check ball vibrating as the oil passes it.

Rob

 

[hz293]

Thanks ROBJ. Yes I do hear a noise when it won't lift. Now I feel better about it. I don't always know how much I'm actually trying to lift.

Harris

 

[patrick_g]

Listening for that pressure relief is not a bad idea. When my Kubota was new I popped an O-ring on the FEL trying to lift too much. Man did it spray a lot of oil around with no way to shut it off as long as the engine is running.

I replaced the O-ring and had no repeat. Don't know if the relief valve didn't or the O-ring was at fault.

Pat

 

[AndyMA]

Another way to go overpressure is for example to dump your bucket half way and then push the edge into some rigid object. I actually did this with 4 foot long forks which give a much longer moment arm and create considerably higher pressure. I've done this on a couple of occasions and blown cylinder seals. The pressure appears to build in a place where there is no overpressure protection.

Andy

 

[RobJ]

Listening for that pressure relief is not a bad idea. When my Kubota was new I popped an O-ring on the FEL trying to lift too much. Man did it spray a lot of oil around with no way to shut it off as long as the engine is running.

I replaced the O-ring and had no repeat. Don't know if the relief valve didn't or the O-ring was at fault.

Pat

You can always find a weak spot in the system. A hose could blow or something could break before the bypass kicks in(hopefully not). Nothing like an oil bath to clean things up.

 

[john_bud]

Andy,

You are right, if you tip the bucket and catch the edge on an immovable object, the pressure will build up against the spool in the loader control. As the spool is closed and the pressure relief is on the OTHER side of the spool, the pressure will build until something gives. On the bright side, it won't gush out while running as long as you don't use the loader.

Yet another thing to watch out for, thanks!

jb

 

[Soundguy]

I have a Kubota B7510HST and have a question about trying to lift when the load is more than the FEL or 3ph will lift. Is there a bleed off valve? If there is when it operates, does it lose hydraulic fluid? Can someone tell me how the system works?

Harris

Yes.. your 3pt and loader should have a relief valve in the system. as a prcatice.. i wouldn't make it a 'goal' to try to lift items untill the relief pops.. but as it happens occasionally during normal use.. It isn't a problem.

You will probably find that your 3pt will lift more than your loader.. It's a geometry thing... While your lift is pretty stout, and if you overload it.. it's relief will pop without any structural damage.. do be carefull aboput laoders.. you can get them in positions where the tractor is pushing against them.. and you can bend piston rods.. or breaks welds due to extra legerage items in front of the bucket can put on the system.


You don't have to treat it with kid gloves.. it is a work tool.. just don't 'over' do it.

Speaking of 'overdoing it... How about this.. put just enough pressure on it till it gets ready to break.. then stop there.. or back off.. (grin)..

Soundguy

 

[RobJ]

Speaking of 'overdoing it... How about this.. put just enough pressure on it till it gets ready to break.. then stop there.. or back off.. (grin)..

Soundguy

People would ask me how much torque can you put on a bolt. 1) tighten slowly, 2) you can feel it sort of giving way 3) when it breaks....back off just a bit. And you are at max.

It's a "feel" thing. I can do it...others twist bolts off. Go figure.

 

[Soundguy]

Yep.. the old.. "Tighten them till -just before- they break"... advice

Gotta love it.

Soundguy