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Thread: JCB 801.4 Rotary Joint

  1. #1

    JCB 801.4 Rotary Joint

    Hi this is my first post, I have done some searching and have drawn a blank so sorry if this had already been covered. I have a 1996 JCB 801.4 which I owned for a few months for a renovation, the last owner had it for 12 years but only did 25 hours in that time, it currently has 3400 hours.

    Last week I was digging a soakaway and lifted the blade to move and it slowly dropped again. It would lower fine and lift the machine but not stay up. I then noticed a hefty leak from the undercarriage but didnít have time to look further. A few days later I started her up and the blade worked fine but the dripping leak was still there but not as bad. All the hoses looked fine and although difficult to see I narrowed it down to hydraulic oil seeping from the top seal of the Rotary Joint. Although I have no plant experience I consider myself reasonably handy. Can anyone tell me how easy they are to remove and do you need any specialist tools? There is little space around the rotary joint and it looks a pain to access. I am hoping a good clean and a new seal kit might do the trick, either that or just keep topping up the oil until it gets too bad. Once refitted will it need bleeding? If anyone can point me towards a maintenance manual that would be great.

    On another note I get a grinding noise coming to a stop having been using the slew in either direction, I guess something to do with the slew brake? All the bearings are well greased, apart from that it does everything it should, thoughts?

  2. #2
    Admin Muz's Avatar
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    Quote Originally Posted by Bradders8014 View Post
    Hi this is my first post, I have done some searching and have drawn a blank so sorry if this had already been covered. I have a 1996 JCB 801.4 which I owned for a few months for a renovation, the last owner had it for 12 years but only did 25 hours in that time, it currently has 3400 hours.

    Last week I was digging a soakaway and lifted the blade to move and it slowly dropped again. It would lower fine and lift the machine but not stay up. I then noticed a hefty leak from the undercarriage but didnít have time to look further. A few days later I started her up and the blade worked fine but the dripping leak was still there but not as bad. All the hoses looked fine and although difficult to see I narrowed it down to hydraulic oil seeping from the top seal of the Rotary Joint. Although I have no plant experience I consider myself reasonably handy. Can anyone tell me how easy they are to remove and do you need any specialist tools? There is little space around the rotary joint and it looks a pain to access. I am hoping a good clean and a new seal kit might do the trick, either that or just keep topping up the oil until it gets too bad. Once refitted will it need bleeding? If anyone can point me towards a maintenance manual that would be great.

    On another note I get a grinding noise coming to a stop having been using the slew in either direction, I guess something to do with the slew brake? All the bearings are well greased, apart from that it does everything it should, thoughts?
    Hi Bradders welcome. The rotary joint is simple enough. But be certain it is that thats at fault first, and that the oil isnt coming from somewhere higher up. Manys a job has been a red herring until you are certain where the leak is .. Sounds like you are fairly certain, but just double check. Theres quite a few seals and rings in there, just be methodical in your strip, and above all colour code using coloured bag ties or similar EVERY hose you take off from the joint input on the top, to all the ones down the side, they are very easy to mix up and could take a while to sort back out
    Please don't PM me for plant advice.. thanks .. Post in the forum where I will gladly help, as will many of our contributors.. as the info and responses will help everyone else, which is why we exist

  3. #3

    Now sorted!

    Hi Muz

    Just thought I would come back with an update. I finally managed to remove the rotary joint, not something I would recommend to anyone unless absolutely necessary! There is very little space to work in and it comes out via the bottom...rolling around in oil.... Oh what a joy!
    Anyway once removed and separated it was apparent that the male inner piece was scored slightly close to the top seal, whilst the seals didn't look in bad condition the rotary joint separated far too easy meaning it was probably not a tight seal. I ended up getting a used one from a breakers, cleaned it up and fitted an entire new seal kit. After much wresting it was refitted. Thanks for the advice regarding labelling the houses etc, I did a little drawing too as I never would have remembered how to put them back in the correct place!

    In relation to the grinding when I slew, I changed the slew motor oil as well as greasing the slew gear teeth. Whilst the gear oil was at the correct level it was clearly past its best and it was much quieter immediately after the oil change.
    Whilst I was at it I changed the engine oil and filter, hydraulic filter, both air filters and coolant.
    I notice that the fuel in the in line filter was orange. I took the fuel tank off, emptied it and there was a small patch of rust on the bottom. I gave it a good clean out and coated the inside with Por15 before refitting. For good measure I'll probably change the travel motor oil in the near future.
    Triggers brush comes to mind!
    Hopefully this will keep the old girl going nicely during my renovation.
    Thanks for your help!

  4. #4
    Quantity Surveyor on the up ianoz's Avatar
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    Advise i was given , change the final drive oil more regularly than service schedule says .
    Not a lot of oil in them so cheap insurance .

  5. #5
    Admin Muz's Avatar
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    Quote Originally Posted by Bradders8014 View Post
    Hi Muz

    Just thought I would come back with an update. I finally managed to remove the rotary joint, not something I would recommend to anyone unless absolutely necessary! There is very little space to work in and it comes out via the bottom...rolling around in oil.... Oh what a joy!
    Anyway once removed and separated it was apparent that the male inner piece was scored slightly close to the top seal, whilst the seals didn't look in bad condition the rotary joint separated far too easy meaning it was probably not a tight seal. I ended up getting a used one from a breakers, cleaned it up and fitted an entire new seal kit. After much wresting it was refitted. Thanks for the advice regarding labelling the houses etc, I did a little drawing too as I never would have remembered how to put them back in the correct place!

    In relation to the grinding when I slew, I changed the slew motor oil as well as greasing the slew gear teeth. Whilst the gear oil was at the correct level it was clearly past its best and it was much quieter immediately after the oil change.
    Whilst I was at it I changed the engine oil and filter, hydraulic filter, both air filters and coolant.
    I notice that the fuel in the in line filter was orange. I took the fuel tank off, emptied it and there was a small patch of rust on the bottom. I gave it a good clean out and coated the inside with Por15 before refitting. For good measure I'll probably change the travel motor oil in the near future.
    Triggers brush comes to mind!
    Hopefully this will keep the old girl going nicely during my renovation.
    Thanks for your help!
    Good news , sounds like youare ontop of things nicely there

    Quote Originally Posted by ianoz View Post
    Advise i was given , change the final drive oil more regularly than service schedule says .
    Not a lot of oil in them so cheap insurance .
    Yes indeed We did ours twice a year when the hire fleet was large, most of them, the oil would come out fairly clean but there was always a couple that had been used as wheelbarrows, and the oil was black as the ace of spades and smelled strongly of sulphide meaning it was breaking down, you just didnt know which ones they were till you serviced them.
    Please don't PM me for plant advice.. thanks .. Post in the forum where I will gladly help, as will many of our contributors.. as the info and responses will help everyone else, which is why we exist

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