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Thread: mf3075 link arms bypass

  1. #1
    cooper
    Guest

    mf3075 link arms bypass

    my link arms stoped working on my 3075 yesterday lights come on on the autotrionic box ie up and down lights but nothing happens had it before and messed for ages with the black box under the step and worked all summer till now. as a temp fix dose anyone know if it can be bypast so i can at least get whats on the back off? im sure it can be done so you just have up and down but no draft control or anything is it one of the selinoids on the hydrolic pump cover?

  2. #2
    farmerphilly
    Guest

    Re: mf3075 link arms bypass

    make sure spool lever is neutral?

  3. #3
    kmac
    Guest

    Re: mf3075 link arms bypass

    On the MF's with the bosch valve slice for the hitch you can usually push the rubber cover on the spools to manually lower or raise the hitch. You want to make sure the tractor isn't going to roll because you're right under the tire to reach it.

  4. #4
    MF-ANDY
    Guest

    Re: mf3075 link arms bypass

    Quote Originally Posted by kmac View Post
    On the MF's with the bosch valve slice for the hitch you can usually push the rubber cover on the spools to manually lower or raise the hitch. You want to make sure the tractor isn't going to roll because you're right under the tire to reach it.
    +1
    push buttons on end of lift/lower solenoids. dont thionk it will be electric feed problem if you have lift/lower lights working. have you got hyd oil pressure? are your spools working?

  5. #5
    john8210
    Guest

    Re: mf3075 link arms bypass

    Once went to look at a 3075, someone had removed the hyd panel and replaced with tin plate with toggle switch for simple up / down control. Dealer did not say about it when rang for details, most irritating as we wanted it for ploughing :cry: so must be able to do it fairly simply.

  6. #6
    cooper
    Guest

    Re: mf3075 link arms bypass

    not found anything to press to work arms yet where should i be looking?
    the spooles ect work fine and are out when trying linkage i fitted a new pump last month as old one was very slow. i had this problem last winter with the old pump on thoguth id sorted it redoing wires under the step to the black box as lots where furred up it then worked all summer but i dont know what wire i redid fixed it if any. someone said other day the frost gets in the damp in the connections and buggers them up its just finding witch one are the row of selinoids on the pump cover under the right hand wheel anything to do with it? dont realy want to have to take hedgecutter off my other tractor to use something on the links:cry:

  7. #7
    Fergieman
    Guest

    Re: mf3075 link arms bypass

    The linkage solenoids are under the cab on the LH side. Look behind the LH steps and rear wheel and there will be 2 solenoids opposite one another about 8 inches apart one is up and one is down. There is a black rubber grommet on the ends that you can press a button behind them to operate. I think they are at about a 45 degree angle to the floor. Not the easiest to see but they are there. Solenoids on the RHS are for 4wd, diff lock

  8. #8
    Russell B
    Guest

    Re: mf3075 link arms bypass

    Might be worth checking alternator is working properly ,my old 3655 used to lock out the lift arms after half an hour use but was still charging the battery.
    New alternator cured it these tractors are kittle in the electro dept if the voltage isn't right.

  9. #9
    feilding
    Guest

    Re: mf3075 link arms bypass

    check the fuses above the batteries in the front grill. some are just line fuses or a small fuse box by air cleaner housing, they feed the hydraulic lift.

  10. #10
    massey765
    Guest

    Re: mf3075 link arms bypass

    once had a 3115 and the wire that connects to the battery had corroded in the terminal so looked ok but no current getting thro

  11. #11
    cooper
    Guest

    Re: mf3075 link arms bypass

    havent had chance to look yet but the batterys are buggered have to jumpstart when cold restarts fine when been running for 10 mins. but batterys where fine last winter when the same happened.:cry:

  12. #12
    cooper
    Guest

    Re: mf3075 link arms bypass

    been and tryed it and found the buttons tryed both and nothing so took conectors off and there is power at the lower one when switch is in down and power to top one when its up arms are right up so could be just the down playing up but i supect both as it was both last time. if i have power there will this rule out the black box?

  13. #13
    Fergieman
    Guest

    Re: mf3075 link arms bypass

    If you are pressing the buttons on the end and nothing is happening it is a hydraulic problem. Also if there is power to the 2 solenoids when up/down the electrics must be working OK.

  14. #14
    cooper
    Guest

    Re: mf3075 link arms bypass

    any idea what the problem could be? the pumps new and the spools work fine could the valves where the buttons are be sticking iv orded a workshop man not sure if it will help i could just do with understanding how the system works. thanks for the help so far

  15. #15
    cooper
    Guest

    Re: mf3075 link arms bypass

    just been thinking and there is a diffrent noise when the back windows open almost like a spools open but its not noise gos when you work the spool valve maybe its stuck in lift there again im not sure if this is a new noise

  16. #16
    hoff135
    Guest

    Re: mf3075 link arms bypass

    Hi cooper, here is info on how the rear lift spool works. Might help.

    As you have probably ruled out electronics by pressing the ends of the solenoids, means your lacking hydraulic pressure. As far as i can see you need hydraulic pressure to lower as well as raise rear linkage. SO wondering if you could do a pressure test on the pipe which goes in at port 'p' on the diagram??? (need to ask the pro's first though!)

    If there was pressure then surely there must be a problem inside the spool block itself?????

    There is a no return valve to maintain pressure in the cylinders, i know very little about these things but this caught my attention????

    Im probably talking rubbish, buts its all i can think of by applying a bit of logic to the diagrams below

    good luck


    -----------------------------------------------------------------------

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  17. #17
    cooper
    Guest

    Re: mf3075 link arms bypass

    thanks for the help will have a study of it. what im also trying to work out is do they just work off the 2 large rams to lift and lower? or is it like other tractors and these just asist and if i was to take the pipe off the rams and let the oil out would the arms drop down to the floor?

  18. #18
    MF-ANDY
    Guest

    Re: mf3075 link arms bypass

    the rams are the lift rams not assistor rams, there isn't one inside' so yes loosening a ram pipe will lower the arms.

  19. #19
    jthomsonagri
    Guest

    Re: mf3075 link arms bypass

    Sounds to me like the spool could be stuck in the lift position. I would slacken pipes like you said and let arms drop then tighten pipe back up and see if the arms lift when you start up.

  20. #20
    hoff135
    Guest

    Re: mf3075 link arms bypass

    As you probably know, high pressure oil comes from the pump to the trailer brake, then to the aux spool valves (which are working) then to the spool which controls the rear linkage. So if you have good pressure at the aux spools, then your pump must be working fine.

    That only leaves the spool for the rear linkage??

    you said before that your linkage was slow, which is why you changed the pump, i assume this cured the problem?? if not then perhaps the spool was the problem all a long??

    I can post the complete diagram or the entire hydraulic system if you wish??

    hoff135

  21. #21
    Cowabunga
    Guest

    Re: mf3075 link arms bypass

    Quote Originally Posted by MF-ANDY View Post
    the rams are the lift rams not assistor rams, there isn't one inside' so yes loosening a ram pipe will lower the arms.
    If the spool valves have oil and pressure, so will the linkage valves which are in the same circuit.
    They are single acting so no pressure needed to lower, which someone wrongly indicated in a post.

    If all else fails and draft control isn't needed, a t piece could be inserted into one of the rams feed pipe with an extension pipe ending in a qr coupling. Connecting this to a spool valve at the rear will allow the links to work off the mechanical spool lever. Ideally connect it to a slice that has float on it so that you don't have to hold the lever while lowering

    Nothing wrong with leaving it like that permanently if it suits your purpose.

  22. #22
    cooper
    Guest

    Re: mf3075 link arms bypass

    thanks for the replys at least i can lower the post dricer on the tractor thats been stuck up and on there for a few days after the new pump arms where back to full speed. i didnt want to go takeing ram pipes off and stuff if it had lift in the top cover like a 135 dose ect. many thanks

  23. #23
    davidroberts30
    Guest

    Re: mf3075 link arms bypass

    Quote Originally Posted by Cowabunga View Post
    If the spool valves have oil and pressure, so will the linkage valves which are in the same circuit.
    They are single acting so no pressure needed to lower, which someone wrongly indicated in a post.

    If all else fails and draft control isn't needed, a t piece could be inserted into one of the rams feed pipe with an extension pipe ending in a qr coupling. Connecting this to a spool valve at the rear will allow the links to work off the mechanical spool lever. Ideally connect it to a slice that has float on it so that you don't have to hold the lever while lowering

    Nothing wrong with leaving it like that permanently if it suits your purpose.
    done this with a 3650 that was only used for trailer work and a little fert spreading
    just piped the arms into the spools

  24. #24
    cooper
    Guest

    Re: mf3075 link arms bypass

    bit of a update got arms down not quite how id hoped no slow way just blew oil all over the place and droped . started it back up and arms went back up. only problem was i had to got pull a stuck manito out after geting back to the yard had a screaching noise and steering went hard spools still work and noise gos when spools are in pump cover was red hot so think its trying to lift the arms all the time hence its been contant pumping and may have just buggered my 1 month old pump!:cry: will see when its cooled down.

  25. #25
    MF-ANDY
    Guest

    Re: mf3075 link arms bypass

    why did you change the pump? had it disintegrated? if so a piece of swarf could have found its way into the lift control valve and stuck something.

  26. #26
    hoff135
    Guest

    Re: mf3075 link arms bypass

    Quote Originally Posted by cooper View Post
    bit of a update got arms down not quite how id hoped no slow way just blew oil all over the place and droped . started it back up and arms went back up. only problem was i had to got pull a stuck manito out after geting back to the yard had a screaching noise and steering went hard spools still work and noise gos when spools are in pump cover was red hot so think its trying to lift the arms all the time hence its been contant pumping and may have just buggered my 1 month old pump!:cry: will see when its cooled down.
    Think there's a safety valve to dump pressure though, on the right hand cover?

    Overload relief valve on the 135 make a hell of a screech, but it says that your not meant to let it blow off for any length of time. not sure if the 3075 one would screech though.

  27. #27
    Orcadian
    Guest

    Re: mf3075 link arms bypass

    It could be one of your green buttons either stuck in or one on the wing got wet and shorting out causing the lift to be in constant pumping

  28. #28
    hoff135
    Guest

    Re: mf3075 link arms bypass

    Quote Originally Posted by Orcadian View Post
    It could be one of your green buttons either stuck in or one on the wing got wet and shorting out causing the lift to be in constant pumping
    running the tractor with the solenoids unplugged would determine if it was electrical or not, would it not?

  29. #29
    hoff135
    Guest

    Re: mf3075 link arms bypass

    Quote Originally Posted by Cowabunga View Post
    If the spool valves have oil and pressure, so will the linkage valves which are in the same circuit.
    They are single acting so no pressure needed to lower, which someone wrongly indicated in a post.
    Why then does the engine need to be running to lower the linkage? even pressing the end of the solenoid doesn't lower the arms unless the engine is running? On my tractor anyway

  30. #30
    Cowabunga
    Guest

    Re: mf3075 link arms bypass

    Quote Originally Posted by hoff135 View Post
    Why then does the engine need to be running to lower the linkage? even pressing the end of the solenoid doesn't lower the arms unless the engine is running? On my tractor anyway
    I've no idea. The rams are obviously single acting. The control valve, where the solenoids are, must divert oil to the rams when activated one way, allow oil to flow through when not, and allow oil trapped in the rams to be dumped back to the sump when activated the other way and therefore lower the links. It is pretty well as simple as that.

    Perhaps you were not pressing the right way or hard enough on the solenoid ends?

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