706 hydraulics inconsistent

Bryant Baecht · Jul 31, 2012

Hi all,
Have an early Farmall 706. Saturday during the heat of the day we tried to raise the platform of my Haybine 479. Wouldn't budge it. Couple of weeks ago raised it no problem. So check the hydraulic level and it's a bit low. So go ahead and top it off, still no lift. Gave up on it ( was about 100 degrees Saturday ) and decided to research it on the web. Went back out tonight, and low and behold it lifted it with no problem, outside temp being about 90. Trying to determine why it wouldn't Saturday, but did tonight. Any ideas? Wouldn't think 10 degrees difference would make that much of a difference but ???...Contemplating maybe dirty filter, let it set, better flow now? Any other ideas?

the tractor vet · Jul 31, 2012

Well if yqa just started the tractor the hyd oil was ambient air temp and it will for awhile TILL everything warms up . Normal temp on the oil is around 150 to 180 Normally but add in extra heat and you may have been way over 200 degrees . Your hitch pump may be getting weak . Now with out flow rating the system on a flow rater at operating temp to check gallons per min. and pressure we are shooten in the dark but a weak pump is my guess . Went thru that on our 706 last year was working just fine when i got off and second shift took over two hours after Dusty was running it it started the i don't want to lift anymore . Next morning i put the flow rater on it and i had 10.5 gpm flow at 2050 lbs for a bit and as the fluid temp started up everything started going down FAST . Put a new 12 gpm pump in it and now it is stayen at the 12 gpm at the 2250 that the relief is .

bbaecht · Aug 1, 2012

Thanks for the reply Tractor Vet. BTW, got a couple of other questions if you would entertain them? Where did you get your flow rater? Also in researching, noticed bad relief valve could be a problem as well. Where exactly does the relief valve go? From what I've found somewhere around or under the seat. Tried to find it last night and still wondering. Is the pump easy to change or did you take it to mechanic? Thanks!

bbaecht · Aug 1, 2012

Hi Tractor Vet,
In reading your response, had another question. Does the 706 have a hydraulic oil cooler? Could be it's getting hot. had a buddy with a skid steer that had the cooler right after the radiator, which, had it's fins bent. He had bad hydraulics once it warmed up because the bent fins on the radiator would pass air. Easy fix would be plugged hydraulic cooler if this unit has one.

the tractor vet · Aug 1, 2012

Ok to start off with i got my flow rater when i bought out 90-95 percent of a closed out I H dealer shop at a auction, along with a ton of special tools . The relief valve is in the right hand seat support . And it probably is the stock one on ours i have replaced it with a higher pressure one . Yes a 706 has a oil cooler and it is up ft and flow for it is controlled by the MCV and MCV pump . The 706 has THREE hyd pumps , one for the rear hitch and remotes one for the steering brakes and the T/A and it also does the cooling and lubing of the rear end, and the PTO has it's own pump built into it . Now back to the flow rater , the one i have will flow 50 gal. a min and at pressures up to 5000 psi.. I do not think that your going to run out and buy one due to cost as the last time i looked one like mine from OTC REBUILT not new will set you back close to 4 grand. This is why i recommend that for hyd problems ya have someone that knows how to test BEFORE ya start throwen money at a problem . My 806 is the next one on the list for a new pump as she is getting slow .

Bryant Baecht · Aug 2, 2012

Hi Tractor Vet,
How hard and what kind of a process is it to change out the hydraulic pump? Still chasing the other potentials, but like to at least get your point of view on changing out the pump if it's indeed bad. Thanks

the tractor vet · Aug 2, 2012

Drain the read end remove the bolt that hold the hyd. pump plat to the rear end and pop it off , unbolt the old pump replace the o/ rings install the new gear on the new pump tighten the nut that hold the gear on clean the gasket off the plate and the rearend houseing install a couple guide studs put the new o/ ring inplace with some grease to hold it there but the gasket on the guied studs and slid the plate back on and bolt down and refill the rear end along with a new filter. done.

Bryant Baecht · Aug 6, 2012

Thanks Tractor Vet for the blow by blow. After reading a few times, I can visualize it fairly clearly. Thanks again! FYI, ran the tractor today in 92 degree weather and had no problems with the hydraulics on the swather. I did check the front of the tractor and getting good air volume being pulled through the radiator so doubting it's got a plugged radiator / hydraulic cooler. The big thing was that we did notice last week that we were low on the dipstick. Did put a bunch in and although it didn't get it going last weekend, it worked middle of last week and today just fine. Was thinking maybe with the temps being what they were ( 105 instead of 92 ), that it might have gotten too hot, and after adding, maybe didn't cool off. But having the proper amount in to start with might be keeping things cool. I'll keep running it and hoping it continues to run well.

706 hydraulics inconsistent

Bryant Baecht

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the tractor vet

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bbaecht

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bbaecht

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the tractor vet

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Bryant Baecht

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the tractor vet

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Bryant Baecht

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