Need help TZ25 3 oint troubles...again!!!

[Soundguy]

what did the cyl bore look like?

if it is good, that points to a exhaust valve or whatever that system uses as a control/check valve on the pressure side of the cyl.

i'm not familiar with that non pc / centering system. I'm more familiar with the older unloading valve style or the previous valve in pump designs on the N fords.

soundguy

 

[jinman]

John, you mentioned being able to hear fluid flowing when you turned the tractor off with the 3ph in the air. Is there any way you might be able to tell if that sound is coming from your lift cylinder or the control valve on the right side of the lift cylinder? If it sounds like the control valve, I have some suggestions for checks you might make, but only if you understand that it is very hard for me to do this by just guessing on TBN. I can make suggestions, but you'll have to be the chief investigator.

Your main hydralic pump sends flow to the 3PH control valve located on the right side of your lift cylinder. This is an open center valve and fluid leaves here and goes to your power steering so that you only have one hydraulic pump that supplies both your 3PH and power steering.

Inside your 3PH control valve, there is a system pressure relief valve that controls the maximum pressure of your hydraulics. This is the valve that regulates the overall hydraulic pressure. Also inside your 3PH control valve, there is a safety pressure relief valve. This is a valve that is set way above your 700 lb lift capacity of your 3PH. For example, if you were to pull a 1200 lb load off a ramp and try to hang it on your 3PH in the air, this valve would lift and protect your 3PH cylinder from bursting. The final valve is a checkvalve that holds the load on your 3PH while the lift lever is in motion and may also be what holds the fluid when your 3PH lever returns to center. I think there is a possibility that this check valve or the safety valve is leaking.

I've attached two diagrams with highlights. The first shows the overall system piping and the red circle shows the 3PH valve and cylinder. The control valve has a red arrow pointing at it. In the second diagram, This is an exploded view of your 3PH control valve. Item 8 is the system pressure relief valve. Item 3 is the safety valve, and Item 2 is the check valve. I would check item 2 and 3 to be sure they are not leaking. I think a problem with item 8 is not likely because you don't have a problem lifting weight, only maintaining it. If item 8 was bad, you'd not have enough lift power for your 3ph and the power steering would be weak.

 

[wny770]

Thanks for the reply. we had about a foot of snow overnight, and once again, it drops.....faster when warm. I will definitely check out to see where the noise is coming from and post back. I too am more familiar with the "other" style, as on my old Massey 35.. The bore, and everything inside looked great when apart, that is what has me baffled. I also have a rear remote on the tractor, to turn the chute of the blower. I would think it would be unrelated? Thanks for the help!!!!!!!!!!!!!!!!

 

[Drewtrac]

John,

I did a little research and found some info for you. New Holland made a running change to the valve assembly in January, 2005. The effective serial number on your model (TZ25DA) was HC20419. It had a dramatic effect on what manufacturers refer to as "leak down tolerances", or the amount that a hitch may leak before being considered to be excessive. Spec differences appear below:

Prior to s/n HC20419-

360 mm (14.17 inches) per hour, with a 149 kg (330 lb) load on the three point hitch.

s/n HC20419 and up -

119 mm (4.7 inches) per hour, with a 429 kg (947 lb) load on the three point hitch.

I'm sorry you have had these difficulties. We have sold many sub-compacts with relatively few problems. I will be interested to see what your serial number is and also if you might be able to replicate the test and provide us with data on your leak down rate.

Thanks, Drew

 

[wny770]

This site is great! My serial # is Z6NXE1056. We've received another 6 inches of snow last night, so...... Later I will blow the driveways, and when the tractor is warm, I will try to see where the "gurgle" is coming from. Thanks guys!

 

[jinman]

Yeah, it seems Drew may be onto something that could really help you. I'll certainly be happy to let him direct you, but if you need more help with diagrams I can do that because I have a simple way of copying them from the NH site as I did before. If you are not familiar with the NH website and how to view parts diagrams, you should give it a try. You won't find descriptions of how things work, but you can see details and part numbers. Sometimes you can also see where parts have been revised or improved.

 

[wny770]

When warm mine will go that 14 inches in a minute easy. It's still snowing:confused2: hard here..... Later I will investigate and post back. Besides this, I really love this thing. I have 2 much larger Olivers and a Farmall, but for the lawn and driveway, this is my "baby". The Sims cab makes it a keeper. I used to have a blower on the big tractor, but lack of heat was not good. Thanks guys!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[wny770]

Well, here's the latest. When warm, it will drop from the full up position to the ground in under a minute with the blower on. The three point lever is centering itself fine. This will drop with the adjustable fluid rate valve open or closed. That "gurgling" sound I heard was the three point "creaking" as it was going down.... This sound was from the center of the unit best I can tell. Should I take this apart in the spring? I really don't know what good it would do. when I changed these parts, everything looked great.... Heck, even the old parts looked great. The cab is a ROYAL pain to take off!!!!!!! Do I save my pennies and try to get rid of it? I would never sell it to someone like this without telling them, I have too much of a conscience. I know I would get killed on a trade.... only 249 hours on it. Any ideas???? On a brighter note....it quit snowing..... Thanks for any help...
PS.....My dealer has never heard of this before..... Has anyone else??? In the attachment below, you can see what I did. I changed 25 and 26.

 

[DSteiner]

Go to https://webparts.pvassociates.net/cnh/webparts/main.php search for TZ25 click on "TZ25A 3 CYL COMPACT TRACTOR (1/05-... " then click on "hydraulic system" then on "07.04.02 CONTROL VALVE".

My suspicions is it is either item "2" Part #SBA340980159 Check Valve
or item "3" SBA340980140 Safety valve are faulty.

 

[Soundguy]

if you tie thge lift handle 'up' does it effect the leak down any?

soundguy