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301.8 cat slew brake

Discussion in 'Compact Excavators' started by Chass, Feb 24, 2015.

  1. Chass

    Chass Well-Known Member

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    Occupation:
    Owner small earthmoving & landscape business
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    Adelaide South Australian
    Hi all got my little 301.8 excavator in the workshop when I slew I hear some clunking noise if I go nice and slow no problem, let go of the lever and I can hear the slew brake jumping missing the spot and clunking until it locks in. I have no idea how it works my back round is diesel mechanic so a little bit. Has anyone got a break down diagram of the slew motor and brake.
    Cheers
    Chris
     
  2. Chass

    Chass Well-Known Member

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    Occupation:
    Owner small earthmoving & landscape business
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    ok gave her a clean and I can get hold of the boom and spin it around by hand then I use the hydraulic controls and slew the machine stop get off and can not turn by hand, so the brake activates sometime so something is not right. help please.
     
  3. Cmark

    Cmark Senior Member

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    At first glance it sounds like you've lost some teeth from the ring gear. Post a serial number and I (or someone) will look to see if there's an inspection cover.
     
  4. Nige

    Nige Senior Member

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    G..G..G..Granville.........!! Fetch your cloth.
    Could it be a missing tooth on the swing pinion..?
     
  5. lantraxco

    lantraxco Senior Member

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    I'll guess busted pistons in the motor, WAG :rolleyes:
     
  6. Chass

    Chass Well-Known Member

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    Owner small earthmoving & landscape business
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    yeh I am thinking it is something serious like that, have you got any picture of the slew motor?
     
  7. Chass

    Chass Well-Known Member

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    Occupation:
    Owner small earthmoving & landscape business
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    Ok got the hydraulic slew/swing motor out look at what I found IMG_1933.JPG
    thanks for your help guys
     
  8. Nige

    Nige Senior Member

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    That would appear to be at least part of the problem. I suggest that you should manually rotate the machine a full cricle with the swing motor still removed and check the condition of the teeth in the ring gear to which that pinion mates. It could be that a ring gear problem caused your swing pinion issue. At least while the swing drive is out it's worth checking to find out.
     
  9. mancavedweller

    mancavedweller Active Member

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    Location:
    Melbourne, Australia
    Ha ha, welcome to the club Chass.

    I've got the same machine and I've actually just been to the gear makers today to drop of my slew motor pinion so they can make me a new one. I'm also going to change out the ring gear (BIG job), and do the swivel seals while it's out.

    I did this repair 7 years ago. Changed out the slew ring and the slew motor. Now my pinion is exactly the same as yours, not a bad run. There's no underlying problem, it's just worn out.

    You'll probably find the ring gear is not in the best of health either. Clean it all out and rotate the top of the machine through its full circle so you can check every single tooth (110 of them). Particularly check the ones where you operate most of the time. In my case that's facing in the direction of the blade with the boom slightly offset to the right for easy viewing of the digging.

    It's a crap job changing out the ring gear. Took off the canopy, boom/stick, counterweight. Then somehow I managed to drag the carcass into the workshop and get it raised up on 200mm square steel tube. Disconnected the impossible to get to hoses on the swivel, etc, then used an engine crane to lift the top of the excavator off the undercarriage. Damn it sounds so simple when I write it, but believe me it was a pig of a job, these small machines are so frustrating to work on. Hopefully you don't have hands like cows udders or the job will send you insane.

    If you've got some heavier lifting gear and plenty room, you shouldn't have to remove the boom/stick and counterweight. I only did that because the engine crane is all I had, plus I didn't have room in my shed.

    I'm still coming to terms with the fact I'm about to do this all over again.

    Good luck with it all.

    Keith.

    While I'm here, does anyone know any part suppliers that might carry spare output shafts for these slew motors. Cat only sell the complete motor. Can't find any here in Australia at present. I often find parts easier to source in the U.S. and they're often cheaper even after I get them flown over.

    REMOVE BITS.jpg ACCESS TO RING GEAR.jpg LIFT OFF UPPER.jpg RAISE UP.jpg
     
    Last edited: Mar 18, 2015
  10. joispoi

    joispoi Senior Member

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    Keith, what's the shaft made out of? What would it take to fabricate one or have one fabricated? That lathe in the background doesn't look occupied at the moment. ;)
     
  11. mancavedweller

    mancavedweller Active Member

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    I got one made out of EN36A before. That's a high strength alloy steel designed for case hardening. I specified that when I went to the gearmakers. Seeing as I got 7 years of hard use out of it, it doesn't seem to be a bad choice.

    There's Bridgeport style milling machine in the shed too. I got refund on that POS in the picture. I want to try and make my own shaft, even have an electric heat treatment oven I built. Problem is finding the right profile gear tooth cutter. I'm not sure if the gear teeth are DP8 or Module 3.0, and the pressure angle could possibly be 25 degrees, not the normal 20 (Google about involute tooth profile if you want to get nerdy with what that means :D). So a lot of yesterday was spent trying to find a cutter supplier that would have a cutter on the shelf so I could check it against the tooth profile. Got a couple of places I can call today.

    The lathe would turn the basic diameters on the shaft, then the milling machine has a dividing head too, so I am equipped to do a DIY job on a pinion. Won't be as good as the great job the gearmakers do but with 2 spares motors who cares.

    Seeya,

    Keith.
     
  12. mancavedweller

    mancavedweller Active Member

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    Took the pinion out of the motor today. Here's some pics.

    Hard to believe but that pinion was still driving on the ring gear. There's a section of the pinion teeth where they are worse and the excavator would "free wheel" at that point LOL.

    No luck finding a matching gear cutting tool, I'll have to try and grind the profile into some high speed steel.

    WORN PINION 3.jpg WORN PINION 1.jpg WORN PINION 2.jpg
     
  13. Chass

    Chass Well-Known Member

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    Occupation:
    Owner small earthmoving & landscape business
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    Hi Keith, mate that looks like a whole lot of fun NOT, I did look on the internet and found a Italian made shaft for these not sure on price maybe a cheaper and easier option go to www.garicambi.it
    Hey Keith send me your email I will send you the info and pictures I got for the shaft. Can not upload it for some reason.

    Cheers
    Chris
     
  14. Chass

    Chass Well-Known Member

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    Occupation:
    Owner small earthmoving & landscape business
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    that's what mine looks like, I could grab hold of the bucket and walk around holding the boom.
     
  15. mancavedweller

    mancavedweller Active Member

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    That's fantastic Chass, cheers.

    I've sent you an email.

    Keith.
     
  16. Timmyxr6

    Timmyxr6 New Member

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    Location:
    South Australia
    Hay mate anychance you could point me in the right direction for sourcing the sharft? I think I'm about to head down this track unfortunately
     
  17. H_alturky

    H_alturky New Member

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    Aug 26, 2017
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    Location:
    Dearborn
    Can anyone help out? I been looking for about 5 weeks for the shaft but no luck.
    Does anyone know where I can get it please don't be ass holes and just help out thank you.
     
  18. Donny Doucette

    Donny Doucette New Member

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    Jun 24, 2019
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    Location:
    Ottawa Canada

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