Track trouble

[Rlh constructio]

I have a hitachi 160 excavator. It has several hours and has had a hard life. The operator started digging today and said the left track would not pull its self. I assumed the track motor went out. Then he called back and said the left track is working but the other one will not pull its self. So I jumped in the truck and headed to the pit. When I got there the left track will not pull itself but you can hear a noise like it's spinning inside also it's like the tracks are in neutral. When you do the tracks free wheel and it pulls the machine when your digging. When you pull the other handle the opposite track turns freely like it's in "neutral" And help would be greatly appreciated.

 

[John C.]

It sounds like the center swivel has blown seals. What model year and how many hours are on the unit?

 

[Rlh constructio]

It sounds like the center swivel has blown seals. What model year and how many hours are on the unit?

6000 hrs. A 2004 year model

 

[John C.]

What I used to do to confirm the problem is walk the machine in one direction for fifty or a hundred feet and note which track is slow. Then rotate the house to the other direction and walk back the way you came and see if the other track was slow now. The hours seem a little low for the seals to be bad but the age of the machine seems about right. You could also pull the hydraulic pump suction strainer from the tank and check for particles of packing. It doesn't take long to repack the swivel but it is a little bit of a pain to get it out of the machine.

Good Luck!

 

[Rlh constructio]

Ok. I tried it. When the machine goes forward the right track is free wheeling but is not pulling. When you tune the machine the same track is not pulling. But both track are turning free. If your on a hill it will take off rolling like the brake is not stopping them. When you pull the handle to the track that doesn't pull itself you can hear a humming noise coming from the center turn table.

 

[John C.]

I think your initial troubleshooting procedure pretty well nailed the problem to the swivel. The only way the tracks can free wheel is if enough flow is going to the motors to release the travel brakes. I haven't heard of that bad of a leak before though. Is it possible that the swivel is hanging loose in the machine and has pressure put on one side or the other?

At any rate you will know when you remove it a tear it down.

 

[Rlh constructio]

I got the center assembly out and pressed apart. There is 5 seals in it and nothing looks cut or tore on the seal but I'll order a new kit and see if that fixes it. I was hopping I would see a seal blowed out but that wasn't the case

 

[Bls repair]

I've found that they usually wear down in stead of tearing apart

 

[Rlh constructio]

I ordered the seal kit. I hope it fixes my problem.

 

[Tones]

I ordered the seal kit. I hope it fixes my problem.

I reckon your problem is in either the drive motor or planetary hub. With what you have described its more likely the spline on the sun gear or motor has failed. If I'm correct continued operation of this machine could be spread debris throughout the hydraulic system or wreck every bearing and gear in the hub. Pull the cover plate off the hub and remove the sun gear and check the spline for damage. You may also may see enough of the spline in the motor checking for damage there as well.

 

[Rlh constructio]

Thank you. I replaced all the seals in the center piviot today and got it back together just. Few minutes ago and it's doing the same thing. I'll try the track motor tomorrow. Thanks for the advice.

 

[Tones]

Ok, what's verdict?

 

[Rlh constructio]

It's in the pit and in a extremely nasty/dusty area. I've not got time to pull it apart yet. I did notice that when you pull the handle to move that side you can hear a whining in that side but no response from the track motor and it still free wheels on that side.

 

[Tones]

The whining you hear is the motor spinning and the fact it doesn't have brakes on that side all indicates the loss of mechanical linkage.

 

[Rlh constructio]

Do you think the trackmotor has went out or the pump stripped. I'm guessing the brake works off pressure and when you pull the handle you relieve the pressure and it lets it spin freely. My guess it flowing through what ever is there to stop
I'm worried in the pit and do not want to tear it down and be down a while waiting on parts. I'd rather get it on the lowboy if I'm able and get it to the shop.

 

[Tones]

I haven't had experience with drives on Hitachi's so I can't comment on the setup in side. The different types I hve come across, some have a coupler between the motor and sun gear, others the sun gear goes straight' into the spline in the rotating group in the motor. Usually the brake requires pressure to release in much the same way as park breaks on trucks. If remove the cover off the track motor there may just be a manufacturer's plate on the motor. The make and model will give you heaps of info on the internet.