Poor Design! Maybe This Will Help The Next Guy

John Saeli

Well-known Member
Bought a 430 Industrial in pieces. Did a lot of work to it, & installed the Model 22 Loader back on. New oil & cleaned screen, at idle she would snap the loader right up, & stall the engine if held against the relief valve.

However, revved up past fast idle & she would make a noise as though she was cavitating, or starving for oil, only when the loader was going up, or when moving the bucket, never on the way down. Double acting cyl's. I cannot understand why it would only make the noise when requiring pressure.

The only thing I did not do was to replace the short piece of hose, at the pump. My guess was that the hose was collapsing. When I removed the hose, it was perfect inside. I then removed the fittings pictured. The ID of everything was .70". Not even .750". The ID of the main pipe leading into the hose is .875". The ID of the hose is 1". I then decided to open the fittings up on the ID, and was able to drill out the inside of the fittings to .875". Great.

However, with the fittings removed, and when I look inside the intake port, I see a final port leading to the gears with only about a 5/8" opening. More restriction that I did not address.

Put it all together & the noise is considerably less, as a matter of fact, I need to rev up past a fast idle to get the noise. The speed of the cyl's also reacts w/ the throttle, which didn't happen before.

The fittings are factory, because of the matching paint that was on them. I assume poor design from the factory.
a247043.jpg

a247046.jpg
 

My loader doesn't have a front Hydrolic pump and th backhoe uses a rear pump. If I could post pictures I would post the case parts diagrams.
 
John,

Is the reservoir mounted higher than the pump? Some pumps need positive pressure on the inlet side to work right. Having the reservoir higher provides this pressure albeit a small amount. This may explain why the inlet is restricted at the pump. If the reservoir is lower I wonder if you have a leak that is allowing air in. Is it possible that the mesh of the screen too small and the oil can't get through fast enough? Does it change if the oil is warmed up? What does it do if you lower the the loader all the way and then try to apply down pressure? Sounds like an interesting/frustrating problem.

Good luck!

Eli
 
Loren: Yes, vent is clear. But. with double acting cyl's, I don't see where it would make much difference. Yes, a cylinder uses a bit more oil one way than the other.
 
From what you describe it sounds like some air is still being sucked in somewhere.
Common for air to get sucked in at a fitting or pinhole in a hose even though you do not see any fluid leaking out.
Even slightly loose bolts on a pump can cause this.
Have you tried increasing the fluid level in the reservoir to eliminate the possibility of the suction line causing a vortex in the tank.

Possible taking it apart and putting it back together eliminated some of the air leaks which caused the improvement.
 
I'm not going to completely discount what you say about air, & will double check the fittings, but the fluid level is full to the fill plug which is high on the frame, far above the pipe going to the pump. I am 100% sure, the improvement came from opening the ID's from somewhat less that .70" to .875".
 

I'm not an expert on tractor hydraulics, but I noticed your picture has hose on the pump and my parts manual calls for tubing. Is it possible you have a higher flowing pump installed than stock? I'm not sure if that would cause your problem or not - the stock pump was 13-1/2 GPM at 1750 rpm at 1750 psi (pump D41914 or possibly D33702). This may be why the engine stalls if the flow is greater than the relief valve can handle??? Just a thought, someone with more smarts and experience than me may have some better advice if I'm way off base.
 
This is a "CASE Model 22 Loader, for 430 and 440 Wheel Tractors". The picture shows exactly what the Parts Book describes. D27932 Hose 1" ID. D25569 15.5 GPM Pump.
 

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