Hydraulic grinding sound (1705)

[edgarrian]

The other day it was pretty cold out when I was taking care of some tasks with the tractor. Its started an odd slightly grinding whistling sound when I would move forward. It was clearly coming from the the hydraulic pump area underneath the seat. So I hopped on the internet and I didnt see a lot of info. I have a technical book for this tractor as well and it didnt have anything in their for trouble shooting. I did see a guy mention something about air getting into the system could be the culprit. I always carry spare maintenance filters and lube for everything we have. I drained the hydraulic fluid, catching it to see what debris could be in there. Looked normal. I removed the filter. It looked fine. Removed the internal filter. It was clean. Put it all back together with new fluid.

So the only thing I can think of is that when I had changed everything the time before. I did have a slight leak on my internal filter. I didnt remove the tire and tightened it up. So maybe it just wasn't quite tight and spending time in the cold may have allowed some air into the system creating the noise. I park my tractor in the garage and there was never any signs of fluid leaking. Even when I was underneath looking at things. I didnt see anything. But all is good. Ive moved wood and cleaned the driveway since the filter and fluid change.

Thought Id mention what happened so others know

 

[Dmacleo]

I have also heard noises when that suction intake filter is not serviced correctly, and it also (on my GC2400 and on company GC1710) only made noises when cold. took me a few to learn how to service w/o breaking.

 

[rScotty]

Glad it's working now. What you are describing sure sounds like a suction air leak. It's probably the most common hydraulic problem and the least well diagnosed. At least it is very localized - because the only place the hydraulics can suck air is in the connection between the hydraulic reservoir (sump) and the hydraulic pump. That includes the hydraulic filter. Everything else in the hydraulc system is under some positive pressure.

Look at all the connections and hoses that pull fluid from the sump into the hydraulic pump. If there is a rubber hose in that group, look to see if the ends of the hose are wet with oil. Or if it drips oil overnight but not when running. Or just replace the hose. The other place to look for suction leaks is where the hydraulic filter O ring seals to the filter mount - but it sounds like you looked there.

If you run the tractor for 15 minutes or so with a suction air leak the trans/hydraulic fluid may look murky because of a million little entrained air bubbles.
Let it set overnight. If the fluid clears up, it has a suction leak.
Another symptom of a suction air leak is that the hydraulic pump will start to either whine or make a sound like it has marbles in it. Both sounds are caused by the pump vanes pulling air and bursting bubbles.
luck,
rScotty

 

[Dmacleo]

What you are describing sure sounds like a suction air leak. It's probably the most common hydraulic problem and the least well diagnosed.

agreed. as someone that actually failed on this twice I cannot stress this section of the system enough.
IIRC (been a year, still only 100hrs since last service) the 1532 I service has an actual filter I have to service, its actually easier than the little items we deal with on a GC series.

 

[edgarrian]

Glad it's working now. What you are describing sure sounds like a suction air leak. It's probably the most common hydraulic problem and the least well diagnosed. At least it is very localized - because the only place the hydraulics can suck air is in the connection between the hydraulic reservoir (sump) and the hydraulic pump. That includes the hydraulic filter. Everything else in the hydraulc system is under some positive pressure.

Look at all the connections and hoses that pull fluid from the sump into the hydraulic pump. If there is a rubber hose in that group, look to see if the ends of the hose are wet with oil. Or if it drips oil overnight but not when running. Or just replace the hose. The other place to look for suction leaks is where the hydraulic filter O ring seals to the filter mount - but it sounds like you looked there.

If you run the tractor for 15 minutes or so with a suction air leak the trans/hydraulic fluid may look murky because of a million little entrained air bubbles.
Let it set overnight. If the fluid clears up, it has a suction leak.
Another symptom of a suction air leak is that the hydraulic pump will start to either whine or make a sound like it has marbles in it. Both sounds are caused by the pump vanes pulling air and bursting bubbles.
luck,
rScotty

I looked over the fittings as well and didnt see anything wet. I park my machine in the garage and make it a habit to look for leaks when i move it out. Definitely had a nice whine to it. Pretty concerning considering I feel like i take pretty good care of the tractor. All is well as I used the tractor again this morning. I moved some firewood into the garage. Now i need to order a filter and some more oil.