1. Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

312 tracking problem

Discussion in 'Excavators' started by JPCobra105, Feb 17, 2010.

  1. JPCobra105

    JPCobra105 Well-Known Member

    Joined:
    Mar 22, 2008
    Messages:
    67
    Occupation:
    owner/operator jpexpress demolition and excavation
    Location:
    long island
    i have a tracking problem with my 97' cat 312.
    it will track normally for a few seconds and then slow down. as soon as i move any other functions (while tracking) it speeds back up to normal. let go of the function and it tracks normal for a few seconds then slows again.

    it only does that when the travel alarm doesnt go on. when the travel alarm goes on it tracks fine. but the alarm will only come on every 10 or 15 times i try to move. same problem in high and low speed. any ideas or suggestions?

    if i switch to the manual override and shut the computer down it seems to track normally.
     
  2. JBSSU

    JBSSU Member

    Joined:
    Feb 17, 2010
    Messages:
    22
    Location:
    Northeast USA
    The travel pressure switch has failed. It is on the front of the main control valve near the top. There are 2 little green switch's there. one is a travel pressure switch & one is swing/implement pressure switch. I forget which one is which, change them both they are cheap.
     
  3. CRAFT

    CRAFT Senior Member

    Joined:
    Jan 6, 2010
    Messages:
    929
    Occupation:
    30 yrs Owner/Operator
    Location:
    100 M H,BC,Canada
    Just out of curiosity how many hours do you have on the machine ?
     
  4. JPCobra105

    JPCobra105 Well-Known Member

    Joined:
    Mar 22, 2008
    Messages:
    67
    Occupation:
    owner/operator jpexpress demolition and excavation
    Location:
    long island
    about 2500 hours
     
  5. JBSSU

    JBSSU Member

    Joined:
    Feb 17, 2010
    Messages:
    22
    Location:
    Northeast USA
    I know it may be hard to beleive that a pressure switch would cause such a problem, but from what you're describing it just may be that simple.These 2 switches are what operate the AEC (Automatic engine speed control function)I think what is happening is when you travel the travel pressure switch is N.G. & the engine speed is coming down to 1300rpm after 3 seconds, the minute you activate another function the imlement pressure switch will raise the engine speed back to high idle & the machine will speed up again. By putting the machine in backup these AEC is disabled & the engine will stay at high idle all the time. Try turning off the AEC by pressing the button on the dash panel, if your problem goes away the pressure switch is the culprit. (every time you turn the ignition key off & back on again the AEC will autmatically come back on.)
     
  6. JPCobra105

    JPCobra105 Well-Known Member

    Joined:
    Mar 22, 2008
    Messages:
    67
    Occupation:
    owner/operator jpexpress demolition and excavation
    Location:
    long island
    does the pressure switch have anything to do with the travel alarm not comming on? every so often when the travel alarm works the machine tracks fine.
     
  7. Per Eriksson

    Per Eriksson Senior Member

    Joined:
    Oct 24, 2007
    Messages:
    533
    Location:
    Sweden
    Yes, same switch for both Travel alarm and AEC function, 106-0180
     
  8. CRAFT

    CRAFT Senior Member

    Joined:
    Jan 6, 2010
    Messages:
    929
    Occupation:
    30 yrs Owner/Operator
    Location:
    100 M H,BC,Canada
    Been really busy this week ....YAHOOO ! .... uhmmm mine hasn't got much more hrs on it than yours, with the age of the 312 and sitting around so much, the green anti-freeze failed (methel glycol)...because of that I had other issues that showed up.... we beleave that caused my rad to partially plug-up, as a result it was over-heating at times badly every time the air temp went over 70 F ...we think that it cooked some of the o-ring seals (making them hard ) the oil is bypassing some seals and am loosing track power to one side ..... my Cat (Finning) product support guy backed up my thoughts and seams to think that the rotary manifold is bypassing oil internally ....NO OTHER function is suffering for power but the track motor ....I was told that it is more of a time involved job to replace the o-rings than a cost factor .... maybe when I get pissed enough I will get around to it, right now I just compensate with pedal travel ..... I wound up having to replace the rad (brand new f/Cat) it was pricey and finning had to get it from the main parts distribution back east in the States..... IT IS not a common problem to have rad failure just CRAP happens (Finning had never sold one in Canada before mine) which is nice to know that I won't have to do it again.... as a foot note Rad tech's priced out to re-core the old Rad WAY higher than new .....I was told that the green stuff reacts with the lead solder used in the rad construction, which leads people to call it water stone/calcium build-up .....WRONG ! .....that info came directly from journeyman 30yr+ Rad techs, had a similar problem with a VW diesel .... we now use the Barney Purple stuff (sometimes called Heavy Duty or long life Anti-freeze) in all of my Diesels ... my new 320clu, and Bobcat came with this stuff from the factory (don't mix it with the green )...... a bit of a way around the bush but its the domino effect that can cause alot of greif
     
  9. DGODGR

    DGODGR Senior Member

    Joined:
    Dec 19, 2009
    Messages:
    753
    Location:
    S/W CO
    Every Cat I have purchased (since '96) has come with the extended life antifreeze. I have had no problems with it. I have heard (never happened to me) that you can't mix extended life AF with conventional AF or it will gel. The reason I posted is because of your comment about the Bobcat AF. I have (2) Bobcats, both were bought new in '06. Both of mine came with propylene glycol instead of ethylene glycol. My understanding is that all Bobcat AF is propylene glycol. This is not the same as the extended life AF. My understanding is that it actually has a shorter life cycle than the ethylene glycol. It is, however, more environmentally freindly. All that being said, I don't know for sure what type of AF you have in your Bobcat. I think it's propylene glycol. I'm mentioning it so that you will make sure before you mix it with the extended life AF.
     
  10. JPCobra105

    JPCobra105 Well-Known Member

    Joined:
    Mar 22, 2008
    Messages:
    67
    Occupation:
    owner/operator jpexpress demolition and excavation
    Location:
    long island
    thanks for the advice. im gonna head over to the dealer on monday and pick up those switches
     
  11. CRAFT

    CRAFT Senior Member

    Joined:
    Jan 6, 2010
    Messages:
    929
    Occupation:
    30 yrs Owner/Operator
    Location:
    100 M H,BC,Canada
    DGODGR you are 100% right it is the propylene antifreeze I was refering to ....just had a brain freeze as to what the correct name was ....LOL .... but some of the guys tend to call it long life ... which is not always the propylene ..... my 312's manual mentions only methyl glycol in it ... they must have (CAT) changed the type after '94 ......my '07 A-300 and '06 320clu both have the propylene in it ....and both shop manuals post a warning "Not to MIX the two types"..... I think where the long life terminoligy came out was thru the auto industry (like-GM, and VW) where they used that stuff in their diesels .... but the point of posting my opinion was that my misfortune of over heating caused the seals to go hard and bypass oil to the drive motors .... another expensive item I had to replace was the throttle control motor, the cables got melted and the plastic suround would not allow throttle movement and fried the control motor as well ....... took a bit of coin and time but all is well now
     
  12. DGODGR

    DGODGR Senior Member

    Joined:
    Dec 19, 2009
    Messages:
    753
    Location:
    S/W CO
    I am not positive, so I request some clarification. I don't believe that propylene glycol is the extended life coolant. My understanding is that the benefits of propylene glycol AF is that it is more environmentally freindly (non-toxic actually), but it does not last as long as standard AF (ethylene glycol). The first time I saw propylene glycol it was marketed under the brand name Sierra, I think (lets all hug some trees shall we). I think that the extended life AF is made up of a different base chemical (maybe the methyl glycol that you mentioned) than either of the other two. The Cat Extended Life Coolant that I use should go at least 3,000 hrs (per the manual). At the 3k hour mark it is supposed to be tested. If the test indicates that the coolant is not up to spec., than an add-mix (Cat Extendor) can be used to extend the service life another 3,000 hours. I currently own (2) Cat machines. My 416C has about 12,000 hours on it now. I have used the extender twice on this machine (coolant was replaced at about 6,000 hrs) and it will be replaced again soon (about 150 hrs till 12k). The other (315CL) has had the extender added once (at 3k hrs). Neither of these machines have had any coolant related failures or trouble. Can someone (in the know) please shed some light on the subject.
     
  13. JBSSU

    JBSSU Member

    Joined:
    Feb 17, 2010
    Messages:
    22
    Location:
    Northeast USA
    Cat Extended Life Coolant is ethylene glycol based... the only downfall to mixing ELC with conventional "green" coolant is you'll lose the benefits of the long life. It will not cause any other problems