Case 440ct hydraulic whine (similar to 440 tire machine)

[Swannny]

Hydro whine loudly appears in between idle and half throttle, quiet at half, loud again in between half and full. Loudest right above idle. Somewhat quiet at full. Noise mostly disappears when boom, bucket, or auxiliary hydro circuit is operated. Noise remains when machine travels. Machine only has several hundred hours.

Basically the rubber line from the gear pump to the "IN" of the loader control valve starts vibrating badly, with the main noise coming from the steel line from the "OUT" of the control valve to the hydro filter... starts resonating/virbrating badly. I can change the noise by grabbing the line and moving it, but cannot make the noise disappear. I suspected gear pump part of the problem, but when under load noise goes away. Auxiliary circuit pressure was 3313psi when oil was warm, not hot. Machine has plenty of travel, boom and bucket power after an hour of hard use in 90 degree temps.

I tightened the band clamps from the suction line out of the tank to the gear pump. No difference.

Before I change the hydro filter and fluid (think it was the original fluid from factory) the noise was worse. Filter sock was dirty (looked like aluminum residue) but no metal shavings, very small amount of shavings came out of bottom of hydro tank, but hardly enough to concern me.

Any thoughts?

Gary - do you have a pic of that hose that was supposed to quiet excessive hydro noise? Thank you!

 

[DIYDAVE]

Hood to hear from you, again, Swanny. I have no specific info or experience, with that machine, other than to say, check the obvious, like relief valve, and any electric solenoid valves. Sometimes it's something simple, like a clamp, with the rubber rubbed through...

 

[Swannny]

Hi Dave! I thought it might be a relief valve inside the loader control valve hanging up, but Gary Hoff said he has seen very few problems with that valve, plus it's an open center...fluid goes the path of least resistance. He suggested part number 87462103 which Case installed after-the-fact as a noise suppressor, but I couldn't find where it was attached.

Found out today that it has been superseded by part number 87670696, and it's basically a short, fat hose that T's off the gear pump outlet hose that feeds loader control valve! The hose is capped and, I guess, acts like a silencer on a gun. Crazy. I was just about ready to take off the gear pump and disassemble it to see if something fishy was going on inside.

Was splitting wood with it late evening yesterday and it was driving me nuts....felt the vibration all the way up in the splitter valve.

 

[Swannny]

Dealer wanted $150 for the part and wouldn't be here till next week, so I had Colliflower make one for me - was $79.

Harmonic whine is same decibel level, but amazingly it cut the spots it showed up in the rpm range in half. Only see it now right before and right after half throttle.

I imagine replacing the steel line out of the loader control valve going underneath the motor to the spin on hydro filter would get rid of the rest of it. Funny how the noise was always behind me and not from the pump area.

Guess Sauer Danfoss pumps aren't manufactured to very tight tolerances. Gehl 5635 and 40 series had quite a few whiners too.

 

[DIYDAVE]

I'd have has colliflower make it too, for that price! You might want to take off the steel line, you are talking about, and have colliflower make up one that is largely hose, maybe with steel ends, if it has any tight turns. I've had them do power steering lines, on my old AC tractors, and never had any more problems. Harmonics is a funny thing, them final drives, on the old AC's sure do sing, in road gear...

 

[GaryHoff]

Swannny, sounds like you have resolved some of the noise. Hose 87670696 was part of a noise suppression kit, hose acts as a accumulator (item 3 in the picture). Making the hose from the pump to the control valve one size larger, will also help with noise. The rest of the kit is mostly foam pieces.

 

[Swannny]

Thanks again, Dave and Gary, for always being willing to help! I dislike whiny machines, kids...windows...whatever else.