damaged slewing ring CAT 301.8

[Max301.8]

Hello Guys,

I bought a CAT 301.8 Mini Excavator with a damaged slewing ring. Now i have disassembled the Excavator and I have some questions.
The hydraulic rotation motor doesn`t look like the original motor (see the picture). At the nameplate I can read "Nachi Hydraulic Equitment".
The slewing ring is certainly damaged, the gearwheel is very worn.

The other question is about the power of the hydraulic rotation motor. If I stand the excavator on the back of the chains, that the front of the chains is in the air, it hasn´t enough power to rotate. Is that normal in this weight class or should it rotate?

Some help would be very nice!
Thank you very much!
Best regards, Max

 

[Nige]

With that colour paint (assuming the rest of the machine is painted Cat yellow) then I would say the motor is not the one that was installed when the excavator was originally built at the factory. Whether it is an identical replacement for the original swing motor/transmission assembly I have no idea but looking at the butchered hydraulic fittings in your second photo it would appear not. None of the 4 fittings in the photo are Cat fittings.

If you lift the machine up on the tracks so that the track drive motors are at the rear and try to swing it might be necessary to drive one track forwards and the other track in reverse to get a machine as small as a 310.8 to turn.

Nachi-Fujikoshi Hydraulics appears to be a Japanese manufacturer making aftermarket parts for mini hydraulic machines. http://www.nachi-fujikoshi.co.jp/eng/yua/
http://www.nachi.de/files/hydraulic-equipment-construction-machines.pdf

 

[Justin Payne]

My Kubota U50 would not either have the power to rotate standing like that. I would think that is normal. I turn like this often, when I need to try to upset the ground as little as possible when turning. But I always us the track motors as well (either one backwards and one forwards, or just one forwards). Otherwise there is no chance..

 

[Rahul chaubey]

Dear sir

I have specific quiry asper below

I have SHUP UNLLOADER(CRANE slewing type) 20T SWL for coal unloading. It is brand new & not yet started operation . But during trial check , I have observed abnormal sound .
This sound is coming after slewing is stop. Since this noise is just after the stop ,hence iam unable to identify the source of sound.

During trial run in china , it was fine , but after dispatched & received at site , when iam operating , then iam experiencing this sound just after stopping the slewing motion.


Till now , I made lot of attempt to find the source of sound , but could not able to conclude . Hence seeking the expert device

One clue- During clockwise rotation , sound is less , but during anticlockwise rotation , sound is appearing in almost all direction

Please help
View attachment Sound appearing location in ship unloader.pdf

 

[clintm]

My guess would be that the bad bearing took out the original swing motor from side loading motor shaft. So I would check this one very good before reinstalling it.

 

[clintm]

My guess would be that the bad bearing took out the original swing motor from side loading motor shaft. So I would check this one very good before reinstalling it. Check the gear teeth mesh on the swing motor also that they are correct with the swing gear.

 

[Justin Payne]

Max301.8: Could I ask you: does your swing motor have oil fill and oil drain plugs for the lower gearbox section of the swivel motor? I am thinking that I should change the gear-oil on mine, but cannot see any plugs and therefore wondering if this is normal or not.. Very appreciative for any answers!