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Revisiting mcv pressures, 1086


tmarch
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Rebuilt mcv last spring because of oil leaks, and also replaced mcv pump. Changed all hydraulic oil and filter. Worked great for 20 hours or so then hydraulic light came on. Lost lube side of ta. Ive changed the hydraulic filter again, it looked clean. I also put anothergasket kit in mcvin case there was blown. Same symptoms. Ta and steering work great. Brakes do hesitate when you use them but its done that for quite a few years. I took pressures again today. Note that when tractor is cold i have about 5 psi of lube in all positions, but it quickly drops to 0 as tractor warms up. Anyway this is what I've got.

At 2300rpm

Ta 230psi lube 0

Middle 210psi lube 0

DD 230psi lube 0

Steering stop is 250psi and 0 lube.

Any help or reccomendations? I tried polishing the valves in mcv in case any were sticking, and the dump valve is operating when i use the clutch. Is my TA on its way out?

16167020881966854470809926789344.jpg

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Lube pressure is left over from regulated.  So, T/A failure has nothing to do with it. (Well, kind of but not likely a t/a failure.)  How are steering and brakes? Hydraulic seat? 

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Kinda wonder if the sealing rings on the TA arent pooched and you are leaking off all your regulated oil there.  Did you air check the supply tubes to the DD and TA and see if they hold air? (Make sure you dont blast air into the lube supply)

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19. LOSS OF LUBE PRESSURE.

A. FILTER PLUGGED.

B. LUBE REGULATOR STUCK.

C. EXCESSIVE TA END PLAY.

D. TA LUBE BAFFLE BENT.

E. SUMP CHECK LEAKING.

F. DUMP SPOOL STICKING OR OUT OF ADJUSTMENT.

G. EXCESSIVE WEAR ON TA SEAL RINGS.

H. DEFECTIVE TELL LIGHT SWITCH.

I. SUPERCHARGE LINE SUCKING AIR.

A. CHECK FILTER.

B. INSURE REGULATOR WORKS FREELY.

C. SHIM TA TO SPECIFICATION OR REPLACE TA.

D. REPLACE TA.

E. INSTALL SUMP CHECK PLUG TO TEST FOR LEAKAGE. CORRECT PROBLEM.

F. FREE UP DUMP SPOOL, ADJUST TO CORRECT SPECIFICATION.

G. REPLACE TA.

H. REPLACE SWITCH.

I. REPLACE SUPERCHARGE LINE WITH 830601 ELIMINATIO

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1 hour ago, J-Mech said:

Lube pressure is left over from regulated.  So, T/A failure has nothing to do with it. (Well, kind of but not likely a t/a failure.)  How are steering and brakes? Hydraulic seat? 

Steering is good, brakes hesitate. Pedal goes low the builds pressure and pedal rises. Been doing that long before i had mcv issues. No hydraulic seat.

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1 hour ago, Cdfarabaugh said:

Kinda wonder if the sealing rings on the TA arent pooched and you are leaking off all your regulated oil there.  Did you air check the supply tubes to the DD and TA and see if they hold air? (Make sure you dont blast air into the lube supply)

No I wasnt aware of this.

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Your brakes being hesitant is more than likely air in the brake lines. Obviously mcv pump is in good health, and I would say the filter isn't plugged or sucking air if you have 250 t.a. I bet a valve is sticking somehow. Did you follow the torque sequence on the valve body? I don't recall what it is, but I remember reading a while ago about it and it was deemed critical. 

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22 minutes ago, MinnesotaFarmall said:

Your brakes being hesitant is more than likely air in the brake lines. Obviously mcv pump is in good health, and I would say the filter isn't plugged or sucking air if you have 250 t.a. I bet a valve is sticking somehow. Did you follow the torque sequence on the valve body? I don't recall what it is, but I remember reading a while ago about it and it was deemed critical. 

I torqued bolts to 25ft. Lbs and pump bolts to 20ft. Lbs. Couldnt find anything on an actual bolt sequence or order. I figure the brakes are probably worn linings or seals since im sure they havent been touched in at least 30 years. I was going to check some of the valves in mcv to make sure they are free.

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I had a friend of mine that fix’s IH tractors too and he had a similar problem and the TA was put in a year ago , new pump and he fought with it for a couple days , low psi on the lube when he turn the wheel and it would lock up . Found that hyd pump was bad after messing with it thinking there was a lube leak . I would tell you to check the inlet fitting in the brake valve too , there is a restrictor in there that controls the oil and they can fall out and the oil will return to sump .  Pull the MCV and remove the pump off the valve and fill the big hole on the pump with diesel fuel , turn the pump over by hand with your thumb over the small port on the pump , if it won’t blow your finger off the hole the pump is bad .
‘Danny 

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4 hours ago, DirtBoyz07 said:

I had a friend of mine that fix’s IH tractors too and he had a similar problem and the TA was put in a year ago , new pump and he fought with it for a couple days , low psi on the lube when he turn the wheel and it would lock up . Found that hyd pump was bad after messing with it thinking there was a lube leak . I would tell you to check the inlet fitting in the brake valve too , there is a restrictor in there that controls the oil and they can fall out and the oil will return to sump .  Pull the MCV and remove the pump off the valve and fill the big hole on the pump with diesel fuel , turn the pump over by hand with your thumb over the small port on the pump , if it won’t blow your finger off the hole the pump is bad .
‘Danny 

Are you talking about the valve on top of the mcv? Hoping i dont have to pull the mcv again but I would like to check all that i can with it installed first. So what ended up being wrong with the other pump? It would supply enough pressure on the high pressure side of mcv but it didnt have enough flow?

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The pump was the problem , TA pressure where fine and when he would turn the wheel to the end stop lube psi would go to zero and steering would lock up . If he shut the tractor off and restart it the steering would work until he would turn to stop . The oil was cold and when it got warmer it would happen faster , replaced the hyd pump and it fixed the problem . Make sure you take the pump off the valve and test it like I was telling you in the other post . How is the hyd oil and filter and do you have Hy Tran in there ? If you are running the farm store oil or off brand oil drain it and put Case IH Hy Tran in it . The reason for this is the aftermarket oils can be to heavy weight oil and won’t pull it through the filter and will damage the hyd pump .

I would tell you to put the 1586 regulated piston springs , this will bump the TA psi from 250 up to 300 psi . You will want to pull the valve one more time to change the spring and check the pump . While it’s off and you want it to steer a lot easier remove the steering relief and turn the psi up on this too .  The steering relief is in the bottom right hand corner , after it’s out clamp it in the vise with a rag around the valve so you don’t damage it . Then use a good screwdriver and turn the flat blade screw in until you can see two treads inside the valve , then reset the side of the valve with a center punch where the old punch mark is , this will keep the screw from backing out . Make sure you install a new oring from Case IH on the valve before installing in the valve .

Danny 

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Hydraulic oil and filter are new. Just changed filter last week again when i had mcv pulled. Any way I can check mcv pressures but eliminate the brake circuit from the test so i can rule that out?

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5 minutes ago, tmarch said:

Should i see a spike in pressure or no change?

It should shut the flow off same as plugging line. Should raise pressure as there is normal slow flow through valve to replenish reservoir. More interested in effect on lube pressure.

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20 hours ago, snoshoe said:

It should shut the flow off same as plugging line. Should raise pressure as there is normal slow flow through valve to replenish reservoir. More interested in effect on lube pressure.

No change in pressure.

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my 806 is doing something similar. when tractor is cold i have 20 lbs lube psi. i have a gauge on it and as working the tractor the pressure keeps dropping to about 4 lbs once its warmed up.  kinda seams we have a similar problem. IT manual is no help. and have checked pressures like you have . but other than someone saying TA is on its way out, i would also like to know what causing this.

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  • 3 weeks later...

I am hoping that isn't hytran...... It should be red. Or close to it.... Yes, that's a little bit, but doesn't look terrible, and depends on where and how you got it. How long did it sit in the bottle before pic?

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I bled the brakes last week into this bottle and noticed the bubbles. I did more testing on the mcv today and when i was done I decided to pull the plug on the bottom of the mcv where the supercharge line used to go (eliminated). I didnt drain the whole mcv, just this little bit into the bottle. Picture was taken just a few minutes after.

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