Bump up lift capacity of L3400/LA463 Loader

jfay · Jan 11, 2009

Jimainiac:

The fill port for the hydraulic fluid is way above the fill level on my L3300, at least a foot. So the vacuum won't pull any fluid in. All it needs is a few inches. The vacuum will pull hard while the hydraulic system is closed, but when you unscrew the pressure relief port, the air is bubbled up through the hydraulic fluid and goes out through the vacuum. Give it a try when you get the proper gauge. I got mine from Northern Tools for $20.

jimainiac · Jan 11, 2009

jfay, thanks for that explanation of the vacuum process, it makes more sense to me now. In my shop manual it shows the gauge being hooked up to the actual pump area, next to the fitting that contains the relief valve. I wonder if the system pressure is the same no matter where it's measured? Any hydraulic engineers care to comment on that?

bmiker · Jan 15, 2009

What is the size and type of quick connect fitting for a 5740 . I would like to check the pressure . thanks

jimainiac · Jan 17, 2009

bmiker - Are you asking about the quick connect fittings on the loader or the rear remote? On our L3830 the fittings in the two places are different. I used the rear remote fitting, and according to a parts book at NAPA, it is ISO type, which is larger than the ones on the loader. I didn't have to buy one, since the dealer provided two male connectors to go with the female connectors on the remote.

FishAlaska · Feb 20, 2009

I was pondering an issue. I see there is a pressure relief on the backhoe controls valve and assume there is one on the loader valve so does an increase in the pressure of the main relief vavle have any effect other than the hydro on the tractor itself?

Increase one without increasing the other valves seems a waste of time.
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2006 BX24, Landpride Box Blade

Zick · Feb 20, 2009

It seemed to on mine. I bumped up the main relief valve by about ~200psi and checking the pressure at the loader hookup, it showed the increase. If I'm correct that is past the point of the loader valve.

john_bud · Feb 20, 2009

FishAlaska said:
I was pondering an issue. I see there is a pressure relief on the backhoe controls valve and assume there is one on the loader valve so does an increase in the pressure of the main relief vavle have any effect other than the hydro on the tractor itself?

Increase one without increasing the other valves seems a waste of time.
__________________
2006 BX24, Landpride Box Blade

Kubota loader valves typically don't have relief valves in them. They rely on the system relief ONLY. The BH's may be powered from a PTO pump, so the controls DO contain a relief.

If you have a BH and want to bump pressures, you DO have to coordinate the change with both system and BH relief.

jopickens · Feb 20, 2009

I have a hoe on my L3400 - does upping the pressure in the main relief valve (which i've read affects the loader and 3pt.) affect the pressure the hoe will see as well? It appears that it's plumbed into the same area etc.

Josh

john_bud · Feb 21, 2009

The BH probably has it's own pressure relief valve. If that is set lower than the system valve, it will pop and bleed off pressure, giving a nominal improvement. It it is set higher than the new system pressure, it will give a nice improvement.

The cylinders on the small tractor BH's are pretty well under engineered. (IMHO) and you may suffer a bent rod. Your call, but I would be leery of it given the fragility of the hoes.

jb

FishAlaska · Feb 21, 2009

On a BX the backhoe is run on power beyond but I thought I saw a relief valve on both the loader valve and backhoe control valves. I dont know if they relieve the increase you make at the main valve though.