Squealing hydraulic pump

[ckeefer]

Looking for some advice.
I have a bolens g274 with a loader. The loader is slow and the hydraulic pump squeals year round, maybe more when cold. Loader lifts a full load. Flow is unrestricted to pump. Pto stalls under load and is driven or activated by the hydraulics. The hydraulic switch on the dash works but the lever on the flow divider valve does not turn off the pto as intended.

Things that I have done:
1 replaced fluid with factory recommended gear oil I believe SAE 80.
2 replaced shaft seal and o rings in pump. Pump gears and bushings looked good with no wear. Pump housing had slight wear visual and to the touch. I would say .003 as a guess.
3 the rear lift spool valve and proportioning valve were rebuilt at hydraulic shop. The 3pt did not work but does now.
4 cleaned filter
5 replaced most o rings and seals.

I believe that the power steering pump is the same as the hydraulic pump and I though about swapping them to see if there is a difference. I would check part numbers first, they look to be the same. I don't want to buy a pump or pto pressure plates if not necessary.

Any help would be appreciated.

 

[glastron23]

here is a manual for a G174 http://sonnys_bolens.tripod.com/iseki/TX1300-1500-OM.pdf

 

[ckeefer]

here is a manual for a G174 http://sonnys_bolens.tripod.com/iseki/TX1300-1500-OM.pdf

I wanted to add that the noise typically goes away when I actuate the loader or 3pt lift and returns when controls are not used.

 

[muddstopper]

Just a thought, I once had a tractor with a 2 spool valve. Seems every now and then I would get a pump squeal and couldnt figure out why. Turns out that the lever for one of the spools was corroded and didnt return all the way to center when releaded. I could bump the control lever and the squealing would stop. I cleaned and lubed the connection on the lever and never had any more problems.

 

[ckeefer]

Just a thought, I once had a tractor with a 2 spool valve. Seems every now and then I would get a pump squeal and couldnt figure out why. Turns out that the lever for one of the spools was corroded and didnt return all the way to center when releaded. I could bump the control lever and the squealing would stop. I cleaned and lubed the connection on the lever and never had any more problems.

I pulled the double spool valve apart yesterday and went through it and made sure that the filter was tight, still loud. Sounds like my 1972 cub cadet hydrostatic. Thanks, I am not ruling out anything and will keep trying.

 

[KWentling]

80 wt oil is way heavier than any I've ever seen in a hydraulic system. That does not sound right. It's usually more like 20 wt.

Kim

 

[ckeefer]

80 wt oil is way heavier than any I've ever seen in a hydraulic system. That does not sound right. It's usually more like 20 wt.

Kim

I agree in general. This type uses gear oil for the manual transmission and the hydraulics off the same reservoir. The manual calls for 80w and I used 80w90. With that being said, maybe I need to use a lower weight gear oil like SAE 50-60, especially in the winter. It has been extremely cold this Nov/Dec around 10-20F in New York.

The manual warns that too thin of gear oil will cause gear wear. However, I also don't want to destroy the pump. I will check with my local hydraulic shop.

Similar to your experience, my backhoe uses automatic transmission fluid which is around 10-20 weight.

Thank you, that may lead me to thinner gear lube.

 

[ckeefer]

Thank you KWentling,
I found the article below which discusses 80w vs trans/hydfluid.
Yesterday's Tractors - Ford 9N, 2N and 8N Hydraulic / Transmission Fluid
So, I am going to try the TS trans/hyd fluid and see what happens. Can't be any worse off than the terrible noise and slow hydraulics.
Chris

 

[dfkrug]

Chris, I have worked on a G274 several times, and I put Chevron 1000 THF tractor-hyd-fluid
in it. That's equivalent to other name-brand THFs, like Kubota UDT, and Deere J20C. Works
well. SAE80 gear oil at 10F is going to be tough to pump.

One of the problems this unit had was deposits in the hydraulic diverter spool, which required
cleaning that all out. Deferred maintenance by prev owner, I would guess.

It does sound like the a relief valve is opening. Have you located the main RV? If so, put a
finger on it when you hear the noise. You should feel vibration there if the RV is opening.

 

[ckeefer]

Switching to THF. Do I need to drain the loader circuit completely too or will the 80w-90 mix with the THF? Much thanks,
Chris