Sluggish hydraulic lift

[zieg72 209]

Looking for suggestions/fixes. I have a 92 520H and the hydraulics to lift the blade are sluggish/sometimes it lifts, sometimes it don't. I just have to play with the handle a couple of times to get it to work. What should I look at first? I haven't a clue on this tractor, my first 520. Thanks in advance.

[kj4kicks 154]

Could be a couple of things.... Are the bushings in the handle worn? If you remove the lower dash plate, you can see what's moving in there.

What does the trans oil look like? Burnt/Low level?

Does the tractor drive ok, as far as speed? (slipping belt? )

[nylyon-(Admin) 7,533]

What Eldon mentioned AND be sure that you have the correct filter on the Hydro. The Hydro filters do not have a bypass valve so if it were replaced with an oil filter that can cause issues. Another issue I have had with my 416-H is the spring pins backing out of the linkages. For me it has backed out of the motion control lever and the steering wheel. Take off the dash panel and check all the pins to be sure they are all the way in.

[T-Mo-(Moderator) 4,569]

Yeah, I was also thinking of low or bad hydro fluid, but I guess there will be some slippage in the transmission also.

Also is the lift cylinder holding it's pressure? There may be some internal damage to it, i.e. seals leaking, etc.

[TT-(Moderator) 1,147]

The relief valve might also be sticking, or an o-ring is messed up on the spool inside the control valve. :thumbs:

[Rod(NASNUT) 1]

be sure that you have the correct filter on the Hydro. The Hydro filters do not have a bypass valve so if it were replaced with an oil filter that can cause issues.

I did not know that I have a oil filter on my Charger 9 I will Change that ASAP.

[TT-(Moderator) 1,147]

I did not know that I have a oil filter on my Charger 9 I will Change that ASAP.

You can get one from your Toro dealer, Rod. P/N is 79-5270 and it's around $10.

Or.....

The Wix # should be 51521 (NAPA), and Stens # is 120-265. Like previously stated -- make sure it's a hydraulic filter WITHOUT a check valve!

Make sure you clean the transaxle / filter area good and blow it off with compressed air before you remove the old filter -- you don't want any dirt getting in there!

[kpinnc 13,860]

Sounds like a mechanical (linkage or spool valve) issue, and the guys already mentioned that. Definately start there!

I wouldn't think low fluid would be the culprit, as the Eatons draw fluid for hydraulics from the very bottom of the sump. I don't THINK the tractor would move if it got that low.

Since a hydro filter has no bypass, I'm wondering if it is possible for it to clog so badly over time as to starve the hydraulics? I think the circuit comes right off the filter into the charge pump, and then on to the spool valve.

Also, you'll be checking the OIL, not the fluid. That tranny uses motor oil for the transmission AND hydraulics.

Not trying to complicate the problem. just other things to check.

Good luck!

Kevin

[.5racer 14]

Are you sut-up in float in your lift linkage ? I would remove the deck and watch the lift to see. Linkage has a cross pin for float or down force , If pin is removed (witch is should be for mowing ) the linkage will cotinue down so deck rides on top of ground surface. With pin inatalled the linkage will shove the deck down in a bow situation and through belts. Might be your just waiting for the linkage to catch up t the lift cross bar ?

Terry

[TT-(Moderator) 1,147]

There is no "float" or cross pin on these tractors. There's an eyebolt threaded in to a trunnion on the lift arm. A chain runs from the eyebolt to the "T" bar which hooks directly into the deck carriage.

You can bypass the chain by using a solid link from the lift arm to the attachment, but not on the newer mowers. (unless you modify the mower somehow.)

[zieg72 209]

The fluid is not on the dipstick, my bad... Filter # PH 710 and it is white. I guess I will start by changing the filter and put new oil in it and see what happens. I parked the tractor a week ago with the blade all the way up. Now it is about an inch from the ground. I haven't noticed any leaks but will look closely tomorrow. Thanks so much for the response. The tractor seems to drive fine so no belt slippage that I can tell.

[nylyon-(Admin) 7,533]

That's the first place to start, while the fluid is low and you're replacing the filter, might as well change the fluid. There is an allen drain plug on the bottom of the axle, drain all the oil and replace it with some fresh 10W-30 and the new filter. It will take about 5 quarts.

When parking you should lower all attachments. First, it is safer and second it's normal to leak down anyway. :thumbs:

[kpinnc 13,860]

Even with a closed center spool valve like you have on the 520, the hydraulics can bleed down when the machine is off for a while. Especially true when you leave an attachment as heavy as a mower deck in the "up" position.

It may take a day or more, but it will leak down. Even more so with a 15+ year old system.

Good luck!

Kevin

[zieg72 209]

Thanks again, I will swing by Toro and pick up a filter tomorrow and change it up. I will post my results.

[T-Mo-(Moderator) 4,569]

I was also going to say it's normal for the system to "leak" down after a while when not in use. But Karl and Kevin already made that comment.

I think you also on the right track with the filter and new oil. :thumbs:

[glenn27 71]

That's the first place to start, while the fluid is low and you're replacing the filter, might as well change the fluid. There is an allen drain plug on the bottom of the axle, drain all the oil and replace it with some fresh 10W-30 and the new filter. It will take about 5 quarts.

When parking you should lower all attachments. First, it is safer and second it's normal to leak down anyway.

Nylon--I have to ask here, 'cuz I'm going to drain and change the tranny oil in my C-120 this weekend---The decal on the belt guard (OEM) specifies 10w-30 motor oil, and so does the original owner's manual--but the PO (who also bought it new)--had marked thru that in the manual--and wrote "Dexron ll" there--and pulling the dipstick and smelling and feelin' it--definately ATF in mine. WTH??

Need some input here??

[nylyon-(Admin) 7,533]

The earlier Sundstrands used transmission fluid and if yours has ATF in it continue to use it as Dexron and oil don't mix real well. The later Sunstrands and Eaton's all used motor oil, so the general rule of thumb is that if you have ATF, use ATF if you have oil use oil.

[refracman 167]

Glenn,

As you know pre 74? had the ATF type for fuild, so with yours could either have a older trans/hydro or someone could have done a complete fluid change and thats why it has the ATF in it.

IMO ATF works better in cold temps. I have done a complete fuild change over to motor type oil bout 4 yrs ago on the GT14loader tractor and when its cold out below 20dgs it dosnt want to go till its warmed up. The rest still have ATF and have no problems when cold.

[glenn27 71]

Yep--10/4--this is a 1975 model--so I was going back w/ what is in there now--definately ATF---actually one manual I saw called for Type "A'--but that hasn't been around for years--so I guess Dexron ( in one of it's variations will work).

Thanks-Steve.

[kpinnc 13,860]

Glen, the Sundstrand manual says you can change even the older ones to 10-30w, but it warns that you must get ALL of the ATF out of the system first.

So you can use either on your C-120, just make it 100% one way or the other...

Kevin

[nylyon-(Admin) 7,533]

Zieg, did the filter and oil change fix your slow hydro?

[kpinnc 13,860]

IMO ATF works better in cold temps.

I can't speak for cold weather, but my Bronco's tranny case was the cleanest thing I've ever seen internally. There was absolutely NO wear on the "working surfaces" either. Just nice and polished.

I've had several tranny's apart, as well as engines with full pressure filtration. I was amazed at how much cleaner the ATF fluid kept all the parts. I don't know whether or not I'd use it in an Eaton, but I'll run it in every Sundstrand I ever use from now on.

Just my $.02...

Kevin

[zieg72 209]

Zieg, did the filter and oil change fix your slow hydro?

Had a busy weekend so I didn't get a chance. I will post the results when I have them. Thanks everyone...

[zieg72 209]

Zieg, did the filter and oil change fix your slow hydro?

I am happy to say the new oil and filter did the trick. My bad, it was really low..... Surprised it worked as good as it did. I found a leaky cylinder/hose by the brake pedal but haven't had time to take the side cover off to see. Patience sure is required to put the oil back in the hydro for sure. Thanks for all the help. I am sure when I get into the leak I'll be sure get advise. Toro is sure proud of their filters, I was looking to see if their was any gold lettering hid...

[nylyon-(Admin) 7,533]

Glad it all worked out for you. The filter is a little expensive, but not even close to the cost of replacing the hydro