The Fordson Tractor Pages Forum

I am still learning on this Fordson for sure !
Tonight I had a lifting boom connected to the 3 point hitch and was lifting a gun safe that weighed exactly 550 pounds.
I had the lift arms as high as they would go, and the pump was growling fiercely. It growled like the pump was deadheaded, similar to a loud bearing that has sand in it sound. ( best way I know how to explain it )
The tractor even smoked, and bogged a touch at idle, more than usual. I was in a position where I had it lifted and was moving the trailer out from underneath it, so it had to stay, until the trailer was clear, for me to lower the load.
Is the pump supposed to growl and almost act like it is putting additional strain on the engine with only 550 lbs on the lift, or do I not have a pressure relief valve set - shimmed correctly or have a problem elsewhere ?
At a bit of a mind puzzler here.
I would think the pump would return the fluid back to the sump, and continue to flow as needed and lock the fluid in the ram, at the heighth desired, without causing what seemed like a deadheaded hydraulic sound.
I sure don't want to damage the hydraulics as I just got them to where they will raise and lower a load correctly !
Thanks.

Did you have the arms as high as they would raise and the lever was still in the raise position? It sounds like the fluid had nowhere to go, so it was dumping over the relief.

Yes, the arms were as high as they would go, and the position control handle was all the way at the top.
Is that normal for the fluid to dump over the relief like you mentioned ?

For if you lowered the controlhandel a little say an inch or so,what Happens then

It did take what sounded like the added strain away from the engine, once I lowered the position control some. The pump was still a bit more noisy than normal though, as I drove the tractor with the pto engaged to put it away, maybe 100ft away. The pump still had a little extra growl to it.
The reason I asked about shims in the pressure relief valve, is when I rebuilt the hydraulic lift top orings recently, I had a gauge plumbed to a port plug in the top of a block off plate, that would be removed, if you wanted to mount a set of remote hydraulics, that sits directly on top, between my legs, on the hydraulic lift top cover.
I could only achieve 1100 psi before the gauge would "click" off and the pressure drop down several hundred psi.
I asked the question on here, and the advice was I was probably getting a inadequate reading at that port.
It will lift roughly a 1200 lb attachment on the 3 point hitch right now, with whatever pressure it is actually making though. I have zero shims of any kind in my pressure relief valve, and wondered if I should try to add a penny behind the spring to bring the blowoff pressure up.

Do the liftarms drop if the engine is off

Livewire84 wrote: Is that normal for the fluid to dump over the relief like you mentioned ?

Yes that's normal. A gear pump is always producing pressure. If your lift is all the way up and the lever is all the way up, the fluid has nowhere to go. If the lever was in a neutral position the fluid could return to the reservoir through the valve, but not when its in the raise position. If it didn't have a relief, it would break the pump case, or some other weak place in the system.

The lift arms do not drop with the engine off.
Thank you for the explanation about how the system works.
I think I will not worry about the growl for now !