Hi Everyone im no professional but my Bobcat cab has come off the undercarrige is it fixable what holds it together. Thanks
It sounds like your swing bearing has failed. Everything is fixable, the question is... is it worth fixing? I've never worked on a Bobcat mini, so I don't know. It will depend on what else got damaged.
Like Mitch said, everything is fixable, but you need to count the cost. If the slew ring bearing separated then it's worn out, nothing to repair, instead requires replacement. There may be other sources for one than Bobcat, but I don't know as I've never done one. When the house came loose from the lower frame it may have damaged the rotary joint and the swing gear housing as well. And you need equipment capable of lifting the entire house to replace the bearing, then there's considerable labor taking the machine apart far enough to access the bolts that mount the house on the slew ring bearing. It may not be a large machine, but it's still big enough to be a pretty good task.
Thanks for the replies when it came lose I let the arm down and it went back together and still tracks and rotates but if you push down hard with the boom it comes apart does that provide any more information as to whats wrong? thanks.
Still sounds like the swing bearing. It sounds a lot more like it should be worth fixing, than the completely separated, flopped over junk pile I was picturing. One things for sure, don't try to use it, or even move it more than absolutely necessary, until you know more.
Think you could post a picture of how much of a gap there is when you push down with the boom? I was picturing a 6" space till I got to the end.
Hi thanks for th replies, the more you push down the more the gap i got a manual and there are 16 bolts that hold the cab/house to the top of the ring ALL of these are out and they are a disaster to work at the main valve block covers five of them and there is a load of pipes in the road as well. Can i weld the cab to the top slew ring? Thanks.
Um, not how I would fix it.
Sure, but even if it survives the inevitable fire the machine will never turn again.....
There are 16 bolts that hold the cab to the top ring if i weld it to the ring why wont it turn? Thanks.
The ring is the race of a ball bearing. How much deflection from heat and shrinkage do you think that bearing is going to take without binding up? I could be wrong, it's your gamble, just not something I would do unless it was absolutely the last resort. Cheers
As lantraxco said, by the time you've finished welding and put the inevitable fire out (because guess what, the bearing's filled with grease which in case you're not aware is flammable) there won't be much left of the machine anyway. Even if by some miracle it didn't catch fire the heat of welding is most probably going to distort the bearing so much that if it doesn't seize up I would be amazed. Bite the bullet, buy some new bolts and install them the way they were supposed to be installed in the first place. My 2c. Do you have any idea how all the bolts came to be missing in the first place...? One would have thought that large long bolts falling on to the ground over a period of time ought to raise suspicions that something was not right.
They dont fall to the ground as they go in from the TOP they just becone loose and fall INTO the cab floor space (I thought you would have known this) Thanks.
I wasn't aware of that. Usually swing bearing to frame bolts are installed up from the bottom through both halves of the bearing and then into the upper frame. You learn something new every day. If you do end up welding the joint please post some photos.
That is very unusual, I've never worked on an excavator where the swing bearing bolts in from the top. That makes it really strange that you were surprised it came apart. If I saw large bolts rolling around in the cab, I'd stop and see why. I agree with everybody else, welding the swing bearing isn't going to work. Are the threads gone from the bolt holes? If so, helicoil them. If not, why not just bolt it back together?
Hi Mitch thanks for the reply.when i say inside the floor i ment under the wakling floor but above the bottom of the cab if u c what i mean I can only get at 3 bolts the rest are blocked by the main valve body and the pipes going to the centre THNGY that takes oil to the tracks and blade its very croeded in the void between the cab wakling floor and the bottom of the cab that bolts to the top of the bearing . Im really puzzled how coud the bolts go in from the bottom of the slew ring bearing unit and not foul the ball bearings etc my bolts only thread into the top part of the ring and hence dont foul the ball bearings I think the threads are ok in the three i can access but i have had 5 pland fitters out and NONE of them will take the job on as the pipes approx 30 off and main valve body have to come out ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Maybe this diagram might help to explain it, however you have to remember that the illustration is somewhat generic and your bearing may be different, but the principle of how the bearing works is good. For example this is a roller swing bearing rather than a ball bearing and has the teeth on the outside of the ring not the inside, but the design works the same either way. Where the bolt holes are shown as being "drilled through" in this diagram they could just as easily be blind holes and threaded so the bolts don't go right through. This sounds like what you've got. You can see that the rollers in the slewing ring are inside both lines of bolt holes, therefore the bolts can go right through the bearing from top to bottom or vice versa if necessary. The upper (revolving frame) of the machine mounts on top of the slewing ring and the outer ring of bolts fixes the upper frame to the bearing. The upper frame is generally either internally threaded or has nuts on top, that way it's easy to see if there are loose bolts or if any have fallen out because the bolt heads are visible from outside. The bottom side of the the bearing is fixed to the lower frame using the inside row of bolts, again these can go bottom upwards or top downwards but generally bottom upwards. So you should somewhere have another ring of bolts that fix the bearing to the lower frame. If you can't see them from outside then I would guess they would only be accessible by going under the machine and getting your head up into the space where the swivel joint that carries the hydraulic oil to the tracks is located. It won't be easy to get at them but it would be nice to know that they are tight, or not as the case may be. I'm still trying to get my head round why these bolts all came loose in the first place. This isn't something that's subject to a lot of vibration that would cause bolts to loosen like that. BTW what part of Norn Iron are you from..? I have friends on the Causeway Coast.
Thank you for your help im 8 miles from Belfast I only have the machine three years its 2004 model it MAY have had a breaker on it would this loosen the bolts?
A breaker eh...? If it ever had one installed that would explain a lot.....a breaker will shake the fillings from your teeth let alone loosen bolts.
Yeah, especially on a little banger like that....