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Case 444 with weak hydraulic drive power

13K views 24 replies 10 participants last post by  JDBrian 
#1 ·
My 1974 Case 444 is weak/slow in drive power. Engine is freshly rebuilt by a real pro... no change in drive power. Original owner guide said I should have 2,000 psi in hydraulics. I bought a gage. Put in fresh 5W-20 oil per Case manual (I only use this to blow snow). The gage reads zero in both low and high range.... I don't get it.... thought I'd see at least a few hundred pounds of pressure given the 2,000 spec. The tractor moves, just slowly. To be clear, 'slow' means it moves with me seated on it, but behaves like 5 HP, not 14 HP. The snow caster is great since it's belt driven off of front of engine. Just can't figure out whether I've got a worn out hyd pump or worn out hyd motor on rear differential.

Can anyone please provide diagnostic advice? Don't want to throw parts at tractor until I know true root cause.
I really need the forum's expertise. Thanks a bunch.

Kevin in Milford Michigan
 
#2 ·
Kevin, welcome to GTTAlk. There are some manuals for the 444 in the manuals section of this forum. You can download them if you don"t have access to them already. If you have the gauge installed correctly it sounds like you have a pump problem. If you give it some time there should be some more experienced people here who can give you some advice.
 
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#3 ·
Welcome, Kevin. Can't help you on your Case. Hopefully someone will be along shortly to help out.
 
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#6 ·
Thank you all for the quick replies. Very much appreciated.
To mikebramel: I only blow snow with this tractor... that's why I loaded it with 5W-20. I will do as you suggest... load the system as much as possible.
It also occurred to me that the line going to the gage may have trapped air. I'm a hydraulics dummy... do I need to pull gage off of line to make sure fluid is up against gage?

To JDBrian and KennyP: Thank you both as well. I will look in the manuals area for diagnostic procedure.
 
#7 ·
I have a couple of manuals for the 400 series tractors that I need to get scanned. I will see if I can't get a couple of them scanned tonight.

I would purge the line going to the gauge to get a more accurate reading. Air compresses more the hydro fluid.
 
#8 ·
Just be sure not to try to hook up the gauge "dead-head" against the pump. Our small "Big Dipper" loader had some issues, so Dad wanted to dead-head the gauge against the pump & just hit the starter with ignition off to get a reading. Don't know where Dad's mind was that day, but he went ahead & did it against my FIRM warning that something would bust. Yep, the engine didn't turn more than 2 pistons up when the pump busted all to pieces the second the pressure built. Dad knows better than that, but must have had a severe brain fart that day.
 
#9 ·
olcowhand-On Case Gt's there is a plug on the valve body to tap into for system drain and to hook up a gauge. Pump won't get dead headed when using that port.
kevincase444- Have you checked the lovejoy coupling, spider for the coupling, and the shaft keys for the coupling? You need to chain that thing to an immovable object and have the travel valve full speed with transaxle in high to get relief to lift. With your gauge hooked up, if you try the hydraulic lift to full travel, you should get about 525psi on gauge. This will head you in right direction. If you have any more problems, feel free to PM me if you want.
 
#11 ·
Kevin, looks like you are getting the needed help. Hope it's a simple fix for you. Good Luck.
 
#12 ·
Wow, this is the BEST forum. The other two I investigated got zero responses to same isse. Thank you all so much.

1. NUTNDUN: If any manuals have diag procedures for hydraulic drive, that would be great. Much appreciated. Pls let me know.
2. OLCOWHAND: Billygoat is correct. I have gage loaded to a test port in the distribution block. No worries about deadhead / burst.
3. MIKEBRAMEL: Since I still cannot get gage to move off of zero when backed up against a brick wall, RPMs high, and pushing implement lift to max, I pulled the
gage any way to see fluid flow before reinstalling.... no change.
4. BILLYGOAT: Pardon my ignorance, but I do not know which parts are lovejoy coupling, spider for the coupling, and the shaft keys for the coupling. Pls advise.
(System seems fairly simple... I'm sure I can follow your guidance.)

Finally, how do I return a Private Message? Billygoat made nice offer to contact directly, but I did not see a 'Private Message' return button.

THANK YOU ALL !! What a great group. Kevin in Milford, Michigan.
 
#13 ·
Maybe this will help!

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#16 ·
cp7 said:
So cowhand is it ok to link him to MTF to the Case Hydraulic Test Procedures Manual that he's needing and that you don't have in the GTTalk files? Or are links to all other Case sites taboo?
I think you know the reason behind what you are trying to refer to. So there is no need for that.

We do allow linking to resourceful public information.
 
#17 ·
#19 ·
The pump has a mounting bracket that attaches to the rear of the engine with four bolts on engine, and two on pump. The shaft from the engine is hooked to the shaft to the pump. The coupling to do this is called a Lovejoy coupling. Google "lovejoy coupling" to get a better understanding of how the pump is coupled to the engine.
 
#22 ·
Here's a link to the Lovejoy site.

http://www.lovejoy-inc.com/

The coupling on the front page is a "typical" coupling used in this application. If you look at the back of the motor on your tractor there should be a shield covering the output shaft and the coupling. The 2 outer halves are keyed to the shafts. 1 oter half is keyed to the engine output shaft and the other is keyed to the pump input shaft. Sometimes the keys get loose and over time get rounded to the point thy don't hold the coupling in place. You might also have 1 or more of the keyways worn. The spider is the flexible piece that's sandwiched between the outer halves of the coupling. Sometimes they deteriorate due to vibration or oil soaking. It may have disentigrated.

If you find you need to replace either the coupling or the spider be sure to get pieces rated for the horsepower of your engine. They all look similar but believe me the lighter duty ones will fail catastrophically if pressed beyond their limits. I remember someone putting one rated for 25 hp on a machine with a 100 hp electric motor. It took less than 30 seconds for pieces and parts to start flying around the room. Fortunately the motor and coupling were about 10' in the air. The spider left skid marks on the walls almost all the way around the room when the coupling failed.
 
#23 ·
kevincase444 said:
Thank you all for the quick replies. Very much appreciated.
To mikebramel: I only blow snow with this tractor... that's why I loaded it with 5W-20. I will do as you suggest... load the system as much as possible.
It also occurred to me that the line going to the gage may have trapped air. I'm a hydraulics dummy... do I need to pull gage off of line to make sure fluid is up against gage?

To JDBrian and KennyP: Thank you both as well. I will look in the manuals area for diagnostic procedure.
Kevin, I have left you an eMail at your business mail address.

I believe the 5W20 is your root cause ... simply not viscous enough for this application. Even thin for winter in your area. I recommend 15W40 for year round in SE Mich, and 10W30 if winter only oil. For sure, 5W20 would not cut it during August ...

Further, I suspect you are tapped in to a lift cylinder circuit, not the main supply circuit. Try exercising the lift while looking for pressure. Up to 600 psi would be normal at lift relief.

This oil will work fine in the lift, but simply bypass the clearances (and not demand much pressure) in the hydraulic motor. Happy to help locally, old friend, if you would like to do that.

Brian
 
#24 ·
Brian, thank you for the offer. I may take you up on that....
On the viscosity point, I only use tractor for blowing snow, that's why the light weight oil (Case recommendation for below freezing). More importantly, I just drained out 10W-30 to perform this diagnosis and before last year, ran straight 30 all the time. I may go back to straight 30 to test your point, but I believe the weak drive has been there across all viscosities. On your other thought of gage being in lift cylinder circuit, definitely not. The test port is right next to 'Spool 1' which is the drive circuit. Spool 2 is the lift circuit Both control valves appear to be sliding their full design lengths.

Mike, how does one determine if there is a problem with relief valve?

p.s. gents..... Found one minor issue.... the 'made in Taiwan' gage I bought from Northern Tool seems to be junk. I removed it from the tractor and hooked it up to an air line. Ran 120 psi from compressor into it and it still reads zero. I need to toss this gage and start over with one made a little closer to home. Stay tuned. I'll be back when I can get real pressure readings.
 
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