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1086 MCV Dump Valve Problems??


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Put a new clutch in our 1086 and trying to get all the adjustments right and can’t the dump valve adjustment right. 
So today I hooked a test light to the positive post on the battery and the test light will light up with the tractor off and the light goes out when the tractor is started. 
Now the problem is it will not come on with the clutch pressed down, I also moved the dump valve with a crescent wrench through its entire range of motion and could not get the light to come on. 
So what do I need to do next? Remove the MCV and see what is going on inside the valve? 
Or can the dump valve be removed without taking the MCV off?

And what do I need to be looking for?

 

Thanks Curtis

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Take sending unit out and install a oil pressure gauge. 

Grease gun hose works good  to get screwed in jus hand tight. 

20 psi or so give or take .

Run it and operate. See what ya got and if it dumps pressure.

 

Can you see that the linkage is straddling that pin  correctly,  in end of dump valve spool and it is actually pulling spool out as it should when clutch is pushed down?

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What is the problem? The dump valve or the light? Head up a slight grade. Push the clutch down. Tractor should start to roll back. As you slowly let clutch out tractor should come to a sudden stop. Let clutch out a little further and tractor starts to move forward again. That is correct dump valve adjustment. Now you can fix the light if you wish.

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The light hast worked in this tractor for a while and I have even changed the bulb, so that’s another problem I have to figure out. 
 

The dump valve isn’t dumping pressure as it has the double clutch feel to it and will roll after taking it out of gear in the shop and will not roll freely pushing in the clutch after you stop

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If it has the double clutch feel, when ta lever ahead,  yes the dump valve is working. That means it dumped pressure when the clutch was down, and locking up the ta after the engine clutch starts moving the tractor. It should lock up(light go out) jus before tractor starts to move.

You didn't include that info in original post.

 

If you didn't back off the tranny brake before you started adjusting. Or take pin out. It is pushing extremely hard more than likely  because of the old clutch adjustments.  That's what snoshoe is referring to below.

Fix the light....or put gauge in to set it for now. Then fixxxx the light. You can ruin a rear-end not knowing that you didn't  have lube......

 

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Here is my procedure for going through all of the adjustments....

First thing that I do is disregard everything that's written in the service manuals.... Not that they're wrong, but when they are set up right they shift nice up and down through the gears if you "think before you shift" hehe.

Check that when the TA is forward in Direct Drive position that the snap ring is bottomed out on the spool- this is VERY important!

First thing to do is to set up the clutch with extra free play. This is usually to your own liking, but I set them up so that the tractor starts to move when the heel of your boot is still on the floor. This makes it easier to feather the clutch for hitching equipment or moving a few feet in the lineup at at the elevator. Don't make any adjustments on the booster, only on the turnbuckle going on down to the clutch release shaft (which requires a 9/16" wrench to loosen the locking block and a large flat screwdriver to turn the adjusting screw on the '86 series and two 15/16" wrenches on the older models without the booster, or two 3/4' wrenches with a booster). Once you have this adjustment where it is comfortable, make sure that the lube oil tellite is operating on the dash. It should come on when the clutch is pushed all the way down. Adjust the linkage so that when in High range, 3rd gear the light should go out before the tractor starts to move as you slowly let the clutch out. Now adjust the transmission brake. Run the tractor at idle speed while the speed transmission is in 3'rd gear. Push on the clutch and count 1-2-3- and try to slowly shift to high range. It should go in nicely with only a "clunk" from the gears. Try to adjust this accordingly. Remember to break loose the jamb nut before removing the locking pin.... they sometimes require a little persuasion.

I have been setting them up this way for quite some time (and follow the order) and it has worked well. Remember to lube all of the shift linkages on top of the transmission from time to time, and you will have a super nice useable tractor

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  • 2 weeks later...

So finally got a gauge on the port where the low oil pressure sensor goes last night. I have 30 psi with it running just above an idle and 20psi when I move the dump valve by hand. 
So it still has pressure above what the low pressure sensor trips at. 
 

Will it hurt anything to have the lube pressure at 30psi or do I need to adjust something to get it down to 20psi??

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....Or the lube pressure regulating valve is stuck. It is behind the lube tellite switch fitting.  It can only be removed after removing and disassembling the MCV as it is retained by a pin. You may be able to get past the pin with a small screwdriver to see if it will move at all.

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57 minutes ago, Farmall Doctor said:

....Or the lube pressure regulating valve is stuck. It is behind the lube tellite switch fitting.  It can only be removed after removing and disassembling the MCV as it is retained by a pin. You may be able to get past the pin with a small screwdriver to see if it will move at all.

How do you figure? Lube regulator should be doing nothing with dump valve pulled. There should be nothing to regulate.

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11 minutes ago, snoshoe said:

How do you figure? Lube regulator should be doing nothing with dump valve pulled. There should be nothing to regulate.

Because the pump by way of the circuitry in the MCV delivers more fluid to the lube circuit than is required. The lube flow regulator controls the amount of fluid to it's circuit, dumping the excess back to the reservoir. If it is stuck it could be causing the higher pressure that he is experiencing.  Lube pressure should be 15-28 psi at rated speed.

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19 minutes ago, Farmall Doctor said:

Because the pump by way of the circuitry in the MCV delivers more fluid to the lube circuit than is required. The lube flow regulator controls the amount of fluid to it's circuit, dumping the excess back to the reservoir. If it is stuck it could be causing the higher pressure that he is experiencing.  Lube pressure should be 15-28 psi at rated speed.

Somewhat misguided. Pump supplies oil to flow divider. Flow divider diverts 5gpm to steering. The rest goes to oil cooler. Return from steering is regulated circuit. Lube is whatever is left of regulated. The dump valve dumps regulated to release the clutches in the ta. No regulated no lube. So with dump valve pulled lube regulator has nothing to do. The op has 20 psi with dump valve pulled and is at regulated max when not. Either dump valve is not traveling far enough. Its exhaust flow is restricted or flow is to high.

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