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cat 312 steering problem

B

Brachuk

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Joined
Mar 9, 2020
Messages
3
Location
Manitoba
I have a cat 312 excavator. The steering on it has never worked properly since we got it. Wasn't bad at first, could run it for a few hours, then notice a loss in the steering. going forward and back is good, boom works good, just seem to lose steering once machine warms up. It now loses the steering quicker. Will run for 20 to 30 min now then lose steering.
I don't use it very often, farm machine, so havnt looked into it . Would like to get fixed before it gets worse or does more damage. Any ideas or tips on where to start looking. Thanks
 
heymccall

heymccall

Senior Member
Joined
Feb 19, 2007
Messages
5,376
Location
Western Pennsylvania
Steering?
Are you referring to rotation of the upper house?

When was the last time the case drain filter was changed?

The case drain filter will affect (and eventually damage) both the swing and travel motors if restricted. Unfortunately, I cannot find out if that vintage even has a case drain filter.
Serial number? 6GK?
 
Last edited:
John C.

John C.

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Jun 11, 2007
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12,870
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Northwest
Occupation
Machinery & Equipment Appraiser
I'm wondering how long people need to get educated before asking a question? People used to call me and ask what their machine was worth and give no information at all. I would come back with I have a car with four tires, four doors and painted black, how much is it worth.
Put it another way, no serial number and there is no way to help you.
 
B

Brachuk

New Member
Joined
Mar 9, 2020
Messages
3
Location
Manitoba
Thanks guys. Serial # is 6LK06640.
I was talking about the travel motors. The boom, and rotation seems to work fine. 8000 hrs on machine. Dont really have any history on the machine.
Thanks for your input too Johnny. It was most helpful.
 
Tyler d4c

Tyler d4c

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Mar 2, 2016
Messages
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Location
Salix Pa
Brachuk said:
Thanks guys. Serial # is 6LK06640.
I was talking about the travel motors. The boom, and rotation seems to work fine. 8000 hrs on machine. Dont really have any history on the machine.
Thanks for your input too Johnny. It was most helpful.
Click to expand...
The seals in the hydraulic center pivot need checked they would only affect the travel motors
 
Nige

Nige

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Jun 22, 2011
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29,316
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G..G..G..Granville.........!! Fetch your cloth.
Brachuk said:
Thanks guys. Serial # is 6LK06640.
I was talking about the travel motors. The boom, and rotation seems to work fine. 8000 hrs on machine. Dont really have any history on the machine.
Thanks for your input too Johnny. It was most helpful.
Click to expand...
Right - now the dog can see the rabbit.........

I would advise caution on the sarcasm. There are a large number of members on here who are experts in their field but despite our best efforts we are not psychics (yet). Psychotics maybe, but not psychic. Trying to give informed guidance without information is like someone walking into a Ford dealer and saying they want parts for an F150. To get information, suggestions, and direction one has to first give at least some basic information. In the world of heavy equipment the Serial Number is the first starting point.

First up the Serial Number you gave is the Engine not the machine, but no big deal. From the engine number comes the machine Serial Number which is 6GK01066.

As Tyler states above the centre swivel is what takes the hydraulic oil from the machine upper frame down to the travel motors. There are a number of seals in it to keep the oil in the various separate circuits apart from one another. Those seals harden with age and oil starts to track from one circuit to another, which produces a loss of track motor performance, especially when you try to turn the machine. This is more pronounced when the oil is hot - back to my comment in post #2. So a Swivel remove and reseal is the first thing on the list of things to do. If you search the word "swivel" in the excavator forum on HEF you will likely find some threads with photos people have posted showing how they did the job. That may also give you some ideas.

Attached is the Parts List and the R&I procedure. When it is disassembled you might be unlucky and discover that the centre rotor (4I-7605) is scored. If that's the case post back for further guidance. DO NOT attempt to reassemble with a scored centre rotor.

So what you have is pretty much all the info needed to do the job. If anything is unclear please ask. If you want to contract it out, I'm available. US$1500/day plus travel time from home base and business class flights (about US$3000 give or take) to your location and back.
 

Attachments

  • 4I-7603 Swivel Group.pdf
    270.7 KB · Views: 20
  • 312 Swivel Joint R&I.pdf
    269.7 KB · Views: 15
Last edited:
mitch504

mitch504

Senior Member
Joined
Feb 27, 2010
Messages
5,776
Location
Andrews SC
Nige said:
If you want to contract it out, I'm available. US$1500/day plus travel time from home base and business class flights (about US$3000 give or take) to your location and back.
Click to expand...

Yeah, but do you bring your own tools? :p
 
B

Brachuk

New Member
Joined
Mar 9, 2020
Messages
3
Location
Manitoba
Wow. Thanks for all the info Nige. I wish I could get that kind of service from dealers I have to deal with. Feel like I owe you at least a cold beverage or 2.
Maybe I could take you out for some ice fishing in exchange for your services.
First time using a forum for a mechanical problem. Really impressed and appreciated the quick responses. Hopefully there wont be any scoring. If there is I may be back for more advice.
Thanks again,
 
Cmark

Cmark

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Joined
Jan 2, 2009
Messages
3,178
Location
Australia
Is there only me on here who doesn't like fixing things by guesswork? Yes, the swivel could be leaking but there are also four crossover relief valves in the system, any one of which could also be causing trouble.
 
Tyler d4c

Tyler d4c

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Joined
Mar 2, 2016
Messages
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Location
Salix Pa
Nige said:
Right - now the dog can see the rabbit.........

I would advise caution on the sarcasm. There are a large number of members on here who are experts in their field but despite our best efforts we are not psychics (yet). Psychotics maybe, but not psychic. Trying to give informed guidance without information is like someone walking into a Ford dealer and saying they want parts for an F150. To get information, suggestions, and direction one has to first give at least some basic information. In the world of heavy equipment the Serial Number is the first starting point.

First up the Serial Number you gave is the Engine not the machine, but no big deal. From the engine number comes the machine Serial Number which is 6GK01066.

As Tyler states above the centre swivel is what takes the hydraulic oil from the machine upper frame down to the travel motors. There are a number of seals in it to keep the oil in the various separate circuits apart from one another. Those seals harden with age and oil starts to track from one circuit to another, which produces a loss of track motor performance, especially when you try to turn the machine. This is more pronounced when the oil is hot - back to my comment in post #2. So a Swivel remove and reseal is the first thing on the list of things to do. If you search the word "swivel" in the excavator forum on HEF you will likely find some threads with photos people have posted showing how they did the job. That may also give you some ideas.

Attached is the Parts List and the R&I procedure. When it is disassembled you might be unlucky and discover that the centre rotor (4I-7605) is scored. If that's the case post back for further guidance. DO NOT attempt to reassemble with a scored centre rotor.

So what you have is pretty much all the info needed to do the job. If anything is unclear please ask. If you want to contract it out, I'm available. US$1500/day plus travel time from home base and business class flights (about US$3000 give or take) to your location and back.
Click to expand...
You better be careful with them last words or you may end up overly busy
 
Tyler d4c

Tyler d4c

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Joined
Mar 2, 2016
Messages
1,819
Location
Salix Pa
Nige said:
Chris, How would you suggest testing them in order to eliminate the possibility..?
Click to expand...
What I did when we had trouble with ours was plug the lines at the drive motor and dead head it and check pump pressure then cap it at the control valve and if on the second test it is way higher it's the seals. Or I guess you could shoot the center with a heat gun if it gets way hot way to fast you have leakage.
 
Cmark

Cmark

Senior Member
Joined
Jan 2, 2009
Messages
3,178
Location
Australia
Pretty much what Tyler just wrote.
  1. Pressure gauge on main pressure test point. Block the sprockets. Note maximum pressure in all four directions.
  2. If one or two of the four pressures is low, exchange the position of the crossover relief cartridges to see if the fault follows. If still inconclusive or all pressures low then;
  3. Disconnect and cap the drive lines at the motors. Repeat the test. Similar readings indicate possible swivel leakage. To confirm;
  4. Disconnect and cap the lines between the MCV and swivel. Test again. If any pressures are still low then the fault is in the MCV or pump control system.
 
Cmark

Cmark

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Joined
Jan 2, 2009
Messages
3,178
Location
Australia
Look, there's every chance that you're right but rather than encourage someone to spend $250 on parts and spend a day frigging about resealing the swivel, which, let's face it isn't a walk in the park, my own personal preference would be to encourage him to spend $150 on a pressure gauge and adapter and troubleshoot it properly. Teach a man to fish and all that.

And before we get into a pile-on, Nige knows me well enough to know that I'm not trying to start an argument, just put forward an alternative point of view. Rational comments are welcome......
 
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