Ford 333 Industrial Tractor Hydraulics

  1. oliwb Member

    Hey, very random but hoping someone might know something about these old things!

    I've just acquired a '77 Ford tractor (think it's basically a 3600 underneath). I got it the night before last and managed to work the loader without issues and back it off the lorry (so far so good). I decided yesterday morning to use it to tow something out the shed but couldn't get the loader to lift at all. It's a Quickie loader that someone has kind of butchered on to the ASC valve.

    So, I just assumed it's probably low on oil. Went and bought the proper stuff for the rear axle this morning from the New Holland dealer. Went and checked the oil level and it was actually already showing as full. I figured it probably wouldn't hurt any to add a bit more so I turfed in an extra litre. This made no difference.

    So then I started loosening off pipe unions to see if I could kind of bleed it. I get nothing downstream from the ASC and get a little bit of ooozing (steady stream but not gushing) from anything upstream of it.

    Not really sure what to try now. I'm wondering if a check valve might be blocked or I'm just doing it wrong somehow. Tried all kinds of combinations which don't seem to do anything. The 3 point linkage doesn't seem to be doing anything either. Before I get into full on strip down mode is there anything else I should try? Is there any way of testing individual circuits without having pressure gauges etc?

    It's just weird that it was all working last week when I saw it and again on Thursday but ever since then nothing....

    Cheers,
    Oli.
     
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  2. addjunkie

    addjunkie Member

    Messages:
    6,105
    Location:
    Northumberland. Reet oot in the sticks
    Hydraulic filter blocked, has it stood a long time. Pumps also have a safety valve which may have lifted and stuck open.

    There will also be away valve/ switch hydrsulic supply, from bsck end to front, is it in tne right place.

    Check simple stuff first.
     
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  3. barking mat

    barking mat Barking at Pigeons

    Messages:
    3,738
    Location:
    Brittany, The Arz Valley.
    We've got taps on certain parts of our tractors hydraulics, and different bits which plug in via quick release hoses.

    Don't know nothing about tractors, but do hydraulics, is the pump producing any pressure, start with a clean filter is a good point.

    I love when hydraulics work, I hate fixing pumps and motors. Well changing them.
     
  4. Agroshield Member

    Messages:
    1,017
    Pumps do not produce pressure. They produce flow. Restrictions to flow produce pressure.
     
  5. roofman

    roofman Purveyor of fine English buckets and mops

    Messages:
    7,527
    Location:
    North West
    :confused:
     
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  6. barking mat

    barking mat Barking at Pigeons

    Messages:
    3,738
    Location:
    Brittany, The Arz Valley.
    so where does the pressurised hydraulic oil come from?
     
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  7. barking mat

    barking mat Barking at Pigeons

    Messages:
    3,738
    Location:
    Brittany, The Arz Valley.
    In my experience a hydraulic pump attached to a 2.5 l 50 hp diesel produces up to 180 odd bar, the flow rate I couldn't quote.
     
  8. Spark plug

    Spark plug Member

    Messages:
    3,664
    Location:
    Durham, England
    I would put my money on a valve or tap being in the wrong position, these old tractors aren’t the most user friendly of beasts, especially with a loader fitted.

    if it was working and now suddenly isn’t then I don’t think it will be anything major.

    If you post your problem over at www.thefarmingforum.co.uk I’m sure there will be lots of people familiar with the machine that can point you in the right direction.
     
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  9. Spark plug

    Spark plug Member

    Messages:
    3,664
    Location:
    Durham, England
    if you have a pump with nothing connected to the output, there will be a flow of oil but no pressure. It isn’t until you connect a circuit with a valve / cylinder / motor that creates a restriction, where there pressure is created.

    Pressure = resistance to flow

    It takes a bit to get your head around but makes sense.
     
  10. oliwb Member

    Thank you gents. I've got the workshop manual here for it (& operator manual too). There's no mention of taps but I'll take another look in the morning in case there is something stealthy hiding. Hydraulic filter is a good point. I'm pretty sure it's been standing for quite a while. Maybe the lorry journey has dislodged something / shaken a heap of junk off the bottom that has been sucked up. Interestingly in the fault finding section of the manual it suggests the pump not being bled / primed but then makes no mention of how to do this haha.

    I'll try that forum too. Thanks
     
  11. 8ob

    8ob Forum Supporter

    Messages:
    6,077
    Location:
    moscow on thames
    The pump on those are mounted a lot higher than the transmission fluid/reservoir they draw from, the pump may well have gulped air coming off the truck and is now struggling to prime. I would be wary of running it too long like this and would try to get some fluid into the pump, better to be safe than sorry.

    Bob
     
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  12. Guzrik Member

    Messages:
    161
    Location:
    Holland Noord Brabant
    But "create" isn't the right word is it?
    If there was only a restriction and no pump there wouldn't be pressure would it?
    Exite is a better term I think (remember I am a non native speaker)
     
  13. oliwb Member

    Oh, I also would strongly suspect that I could well be just using it incorrectly. It does seem like one of those things that if you'd actually plumbed it you'd know. But I know it wasn't done by the previous 2 owners haha
     
  14. carbon

    carbon Member

    Messages:
    1,607
    Location:
    S. Glos. U.K
    Location of pressure relief valve, I think

    E8BA748F-60B3-42A9-A7A3-BF813AE711B9.jpeg
     
  15. oliwb Member

    Thanks Bob... That is actually not a bad point. I wonder if the reverse off the ramp has taken it below the pickup. I think I've got a replacement filter here so will pre-fill it and chuck it on in the hope that it solves the problem.
     
  16. AndersK Member

    Messages:
    927
    Location:
    Sweden
    Pressure (bar) x flow (l/min )/ 600 = power (kW)
    So flow rate is power * 600/ pressure
     
  17. julianthegypsy Member

    Messages:
    2,803
    Location:
    Cirencester
    Is it a dual clutch or independent PTO? If it's dual clutch and you've knocked the pto lever out of gear, you've also disengaged the drive to the hydraulic pump. I've been out to a fordson major where the operator had done exactly that and couldn't get the tipping trailer to move, it was stuck half tipped. Took me ten minutes of looking all around it before I figured it out!
    If it's not that, it will almost certainly be a diverter valve somewhere , often switching flow between the rear linkage and the loader. Are the lift arms moving?
     
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  18. lincoln2013 Member

    Messages:
    62
    South west UK
    I am fairly sure to get the loader to work the leaver controlling rear 3 point linkage needs to be all the way back possibly marked constant pump. Then I think there is another valve which diverts oil either front or back, possibly the one you see in your 3rd pic can't remember whether it needs to be pushed in or pulled out for loader to work but I do remember you have to temporarily release pressure to change it.
     
  19. waddycall

    waddycall Member

    Messages:
    1,152
    United Kingdom
  20. Agroshield Member

    Messages:
    1,017
    Yes. And having this idea in your head helps you to diagnose the problem correctly and sooner.

    Plenty of flow of oil but no pressure, for example, is not likely to be a pump issue but could be the relief valve failing open (the relief valve being shut is what provides the resistance to flow, allowing the pressure to build). If you go into fault-finding-mode with the idea that no pressure = broken pump, you can be diverted from the correct path.

    The guy in the article has rather a different purpose to that of the very practical one of diagnosing a problem on an old digger. As he says, these things often descend into religious arguments. In some ways it is like the dual nature of light: wave or particle. Thinking of it in one way helps to understand one type of problem; thinking about it another way helps in a different class of problem.
     
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