Hi guys.. Im new here.. I have a JD 450G and a Cat 312 that we use on the farm just clearing land.. The 312 has recently got to where it will start spitting and spuddering bad everynow and then and it bogs down bad under load.. I cant work two sticks at once.. I have to roll the bucket by itself to get dirt.. I watched videos on youtube of 312s walking up grades and stuff like nothin.. I pretty much have to use the bucket to walk it up any amount of hill, it wont even spin the tracks over hardly.. Im kinda stumped on what to check? I been searching alot and it looks like it may be a fuel problem :beatsme .. If someone can point me in the right direction on what to check and maybe a reference to where its located it would sure help.. If yall need any additional info on the Cat, let me know and ill try and get it for you but all i know right now is its a Cat 312.. Thanks guys
The first thing to do is find out if its an engine problem or a hydraulic problem. sound like a fuel problem with the sputtering. have you serviced it? fuel filters and air filters if dirty? a serial number (just the prefix) is a must for me so i know what machine we are talking about.
The air filter was really dirty.. I got a brand new air filter ill be puttin in tomorrow, the one in it is fairly dirty.. I blew it out with the air compressor today and it didnt help the problem, actually it got worse but i think that may just have been coinsedence as i was halfway through the day when i blew it out.. Where do i need to get those numbers from Lee?
The PIN is on the right lower corner of the cab on the outside. there should be a tag but if it is missing then it is also stamped into the metal.
is it a 312a? when was the fuel filter last changed? Is the fuel tank clean, no water? has it been sitting around for long? How many hours?
Ours has a water separator in the battery box. Might want to check that- as well as the fuel filter. We rented a 312 once and it acted like yours. I found a bunch of gunk in the banjo fitting on the side of the water separator.
Nothing like having to work on a rental machine... :Banghead
I hear ya, but you just grit your teeth and do it. Hopefully Woodboy's problem is fuel because it's a cheap, easy and quick fix.
Thanks yall.. I will check out the filter and water seperator.. And get the info yall all asked for.. Im not sure on the 312 a, b, or c because all it says it 312 on the body.. Itll be after lunch but ill get the info posted on here..
Serial # is X6LK.... Motor # is 3064 and Model # 312
If you still have the problem after checking your filters,banjos,ect replace the rubber fuel line between the water seperator and the lift pump. This pipe usually can get perished but you wont see any bubbles in the lines because its after the seperator. This problem will make the machine as weak as water
I dont see where i can edit my above post, but here is the correction Machine #- 312 Engine #- 3064 Pin #- *7DK0....* Serial #- *6LK0....*
The transfer pump (lift pump) could be the culprit. Debris can settle inside and clogged the small check valves. The top of the pump can be removed and cleaned out. If the check valves are broken then replace the pump.
Where is that located Lee? I ordered new air and fuel filter today since the one i got was the wrong one.. There is a filter in the top right corner that looks like a fuel filter im guessing thats the only one? I backed off one of the fittings and i could hear it sucking in air so i tightened it back up, added some lucas diesel additive, and fired it up and it purred like a kitten the rest of the day, didnt feel like it had regained all power, but was runnin alot better
WOW ! ....... Talk about skeletons outta my closet ! ..... Here's my story ......... mine ran like a good Timex watch until one day I thought i'd do some preventative maintenance ...... replaced the main fuel filter top right side of the engine .... BTW.... that's where you bleed the air out by loosening the small bolt on top of the fuel filter housing then pumping the manual fuel primer up and down, it's located right on the fuel pump it's part of the lift pump..... I also serviced the so called water separator filter located on the side of the fuel tank, had to take it apart and clean-out the glass, it was so filthy that you couldn't see thru it .... tried to drain the bottom of the fuel tank ..... well it wouldn't drain .... had to poke a stiff wire up thru the bottom to break all the rust sediment loose and then it would drain ... this should/would later be my first clue ..... fueled up the tank and went to work. After all of my good deeds every time the machine got down to 1/2 of a tank the machine would start coughing and sputtering like yours does.... fuel up the machine and good togo until it got down to half again and again ..... was I pissed could not find out why ? .... made some calls and was told that the inlet banlo fitting on the fuel pump has a miniture nylon filter in there .... it was totally caked up with a laquer like crap (that was my second clue later).... cleaned it and went back to work again ..... same thing over and over again, half tank cough-cough ..... HMMMM ! ... made a call again to my Cat guy ... he said, gotta be the lift pump or the primer is leaking, replaced it to a hefty $300.00 parts bill .... went back to work ...... again and again half tank ...#&++~~~***$%#@(*^..... all of the filters including the mini in the banjo never got dirty again during all of this .....this went on for 2 more years.... until the light went on .... I wonder if that water separator is leaking and sucking air? .....BINGO !!! nailed it ... removed it off of the tank cause the damn thing is now obsolete and put a metal in-line filter on, I carry a couple new ones with me in the machine (they're cheap too) now just before the thing runs low on fuel it'll start sputtering, shut it down, fuel up, then a new filter. So now every time I fuel up I drain a small amount outta the bottom of the tank .... rust more rust over and over, but it has been getting less and less too ...... Ohh BTW did I mention, mine too was an Ex rental machine from the Cat dealer thought it was a great deal cause it had very low hours onit. but as it turned out cost me alot of greif and money .... all of the clues pointed out that machines that sit for extended periods should not sit low on fuel............:Banghead :Banghead..........:beatsme........:drinkup
Where's the "delete your post" button?
Okay, another problem.. My right foot control sticks.. Its just kind of stiff, left side is smooth as butter, but the right feels like its been bent or something down low.. How can i uncover the area or what do i need to check? Thanks Also, the machine is in great shape, but using it clearing land i have busted out the front windshield and windshield frame.. Does anyone know where i can get this and other various parts i may need? I tried fleabay but no luck
New guy with a 320b. I'm clearing out 20 acres of sapling maples right. So far, I lost the fuel cap and a boom light to a rogue tree. So far I've kept them off the window! See Lexan as a replacement sometimes.
There's a metal trim piece on the floor in the doorway. Unscrew it and remove it then you can pull the whole floormat out. Dirt and pebbles will get packed under the mat/pedal. Clean everything and lube if neseccary. Your pedals just push a plunger down and if they move freely then you got other problems.
Hey guys, I hope I am not doing something that is frowned on by asking a question in this thread. I figured if you guys are familiar with the 312 then there is no need for me to start a new thread if one of you can answer me. We have a 312CL, I think it is an '06 model, not sure serial # CAT0312CKCBA02296 I am trying to do a full service on it. I am more than capable of doing the work, just not real familiar with these machines. I have read about changing the swing motor oil. Does the swing motor have a seperate system independent of the main hydrualics? I see what looks like a dipstick and a drain tube sticking out the front. Is it as simple as draining out the tube and refilling with 3L of hyd oil? I have also read about changing final drive oil. Does this apply to my machine? I was thinking the drive motors were just hyd motors without any type of seperate resevoir? I drained the main hyd tank and only got about 20-25 gallons out of it. The specs say I should have gotten almost 40 gallons......not even close. Am I missing something or was it just that low? Thanks for any help, and if the is a place to look up "how to's" I would appreciate the links.
There is oil in the planetary part of the final drive that is separate from the rest of the hydraulic system. There should be two plugs on the planetary cover - one for draining, the other for filling. Does the book say 40 gallons for the hydraulic tank? Or total system capacity? Remember that there is going to be quite a bit of fluid in the pumps, lines, drive motors, cylinders, etc.
It says 39.6 gallons in the tank. I know this may only be half of the fluid in the whole system. But then it says 42.8 gallons in system including tank. I know one of those is wrong, there has to be much more than that left in the lines and cylinders. I will pull the drive covers and check for the plugs. Any idea what type fluid goes in there. My Kubota tractor uses the same fluid everywhere. I would guess some type of gear lube for the planetaries?
You don't have to pull anything to see the drain/fill plugs - they're right there on the outside.
I thought those looked like drain/fill plugs, I know exactly what you're talking about. Rotate till one is at the bottom and let it rip. Any ideas on the drive motors or any other fluids I might be over looking?
Not drive motors.....I meant the swing motor. Sorry. Where is that Edit button when you need it?
The right rear door ...... open it .... and look right and a little up, on the hyd tank ..... K .... there is a sight glass for tank level and instructions (in the form of a picture, so that makes it bi-lingual.....LOL) on where the boom and stick should be located in order to get the proper reading, there should also be a cap that looks like a rad cap there (that's for pressure releiving the hyd tank) So once you've done u'r preventative maintenance that should make it easy to know where the level should be. Oh BTW what kind of hrs are on u'r machine ? Have Fun .............. :drinkup
3500 hrs. not sure if the 2000 hr service was ever done so I am doing it now. I found the hyd tank cap. Had to remove a bolted on cover to get to it? You would think it would be easier to add fluid than that. Does the swing motor drive work like the final drives with a seperate oil galley for the gears? I wish there was a way to catch returning hyd fluid. On our dozer(Komatsu D41P) I rigged up a pvc pipe with an elbow. I stick it under the return filter mount, fill the tank with fluid, start the engine and cycle the cylinders. I catch the old fluid while the new goes from the tank to the system. flushes the pump, lines and cylinders with fresh clean fluid. Might be a bit of overkill but it worked well when we got water in the tank(A cousin backed it into a creek,LOL!)
I really sounds like you need to get the omm, The operators and maintenance manual, the book behind the seat. this will give you all the info on servicing the machine including how, when and what oils to use. To fill the hyd tank, there is a plug that is accessible without removing any cover. it takes a 30mm or a 1 3/16 socket. The final drives and swing use 30w oil.
Having bolts on the hydraulic tank fill cap and a pressure release are safety features given the high pressures in these machines.
I don't recall seeing any 12 ton excavator having more than 25 gallons of oil in the reservoir. As long as you fill the tank back up into the sight glass, cycle all the cylinders several times and then set the boom,stick and bucket on the ground in the manner shown on the decals by the sight glass you are OK. The swing machinery, which is what the manufacturers usually call the gear box under the swing motor, will have a drain plug somewhere on the bottom. I've seen most have an elbow from the case that lines up with a hole in the house frame. The ones I've worked on just had a pipe plug in the elbow. Cats might be a little different but probably not much. You do need the operation and maintenance manual and they are not expensive. The local dealer in my area carries them in stock. Your dealer should also. Good Luck!
On the top of the 312's hyd tank (out side) is a cap that is NOT bolted down ....you use a 1/2" drive johnson bar or a long 1/2"drive ratchet drives end straight in ....there is an o-ring seal below the plug/cap ..... the reason I thought i'd mention the pressure cap inside the door is so u don't blow out the o-ring or worse yet have u'r face over the cap when unscrew it ...... the system is pressurized to reduce the foaming in the tank. I too was going to mention the same as Lee-online, get the owners manual ! ...... if there is not one in the 312 then go to Cat and get one, usually they'll give you one if it's not there...... BUT hopefully you don't have a grey market one ...... Good-luck
I got Lee-online's message on my phone just as I pulled up to the parts store to get some synthetic gear oil, got the 30 weight instead. Thanks! I found the OMM behind the seat under a flap type box. All is as fine as frog hair. I got ALL the fluids and filters changed today. The swing drive drain uses a petcock and a rubber hose already attached. It is hiding under a heavy cover right behind the frame under the cab. The specs I printed off the web were wrong as rain, only 26 gallons of hyd fluid in the tank, 43 in the whole system. All that is left to do is drain the water/sediment from the fuel tank valve, another cover to pull I guess, oh goody! It was bought from a CAT dealer here in Ga so I am pretty sure it is not a gray market tractor. Thanks so much for all you guys help. Some time this week I am gonna pull the drive motor's relief valves and see if bad orings are causing a pulling problem. Yall might be hearing from me soon.
Be sure to read the part about changing the hydraulic filter carefully. If it says some thing like "dump the oil out of the canister and discard", don't dump it back in the hole. Trust me. rofessor
Well i feel that its not a fuel system problem anymore.. It doesnt spit and sputter any more and runs good, but now it just bogs down when using the hydraulics and sometimes even completely kills the motor.. It bogs the worst and quickest when using the arm, the boom isnt that bad but still will bog it down actually any hydraulic motion will bog it down except when crawling or swinging around? It has hydraulic oil half way of the sight glass when cold and i also got a hydraulic filter for it today but surely its not the hydraulic filter?
Are you sure this is not a grey market machine? I had a customer that had a 312 a few years ago it had a similar problem. I always felt this machine was underpowered for its size.
If you are ABSOLUTELY sure that the fuel system is not causing the bogging, as I talked about what mine is/was doing at times (which what you're talking about sounds exactly like mine, but I know its fuel supply, rusty tank deposits) .....then there is one more thing that I had done by the Cat dealer .... There is what they call a secret button on the display panel, its a button that is there but not marked to be one .... if you look at the touch pads you will notice that there is a gap, and the covering has a spot where it appears to be a button ..... it is .... sorry I don't remember the sequence :beatsme ..... but when it is pressed combined with another button it will put the computer into a diag mode where the machine goes into calibration of the engine RPM to hyd demand ect ....ect ... and I would not recommend to try it your self I had the Cat guy do mine and it was amazing to watch the 312 rev-up , slow down , bump up the rpm progressively in all 10 throttle positions ... they have to do this when lets say the throttle cables were replaced or linkages repaired on the fuel pump or even worn linkages which is normal....... also what surprised me was that a '94 312 had the electronics of that calibre built in, but when you open the left rear door and the big aluminum thing with all of the wires coming out, well thats the brain box ...LOL ..... now like my '06 320 they're alot smaller in size :cool2 After he did that the machine performed flawlessly ...... NOT saying that this is your cure but it wouldn't hurt to have it done as well before you get all kinds of parts thinking what might be and the coin spent is not wasted sfsracing : thats one thing that every guy wants, is more power but even the greys have the same motor, its all the other crap that is different, all the filters, or stuff with a slightly different size, stupid stuff .... BY NO MEANS am I a grey supporter ..... but there is plenty of poop coming outta the little Mitsi, thats one thing that Cat does is know how to do, put the power to the ground (when everything else is working properly)
WOODBOY ! ... check out the thread "Fueline Banjo Bolt Screen Problem" by ATCOEQUIP ... its exactly what we've been talking about here ..... :drinkup
we had a gray market 312... good hoe, as It's the not too big, not too small type of machine tell-tell sign of a gray market machine... the goofy FM radio... It only goes to 89ish on the dial... We had a komatsu and the 312 , both grays, both goofy radios.. the 312 really good hoe except for the parts availability... long wait times.. sometimes the komatsu... well the pretty paint looked nice... The bad thing... you would hit both sides of a 4 foot ditch with a 1 foot bucket ...SLOOPPY
It was a grey market, thanks for all the help guys.. It ended up being the servo valve wire had tore.. Fixed it.. Ran good till about 2 when a hydraulic line busted and it burnt down.. First hydraulic line ive ever had to bust since having it caused it to burn
Boy you sure had us going there for a while ..... didn't you ..... I don't beleave I read anywhere that you had a torn or burnt anything ..... just that you had a power surging problem or fuel watchamacallitthinggy ..... oh well sounds like you got it licked ...... I guess it pays to know the WHOLE story .... ointhead ......:cool2
It was spitting and sputtering, and sometimes would kill it.. i added some Lucas diesel fuel additive and checked the banjo fittings and it went to running better.. Then after about two days it was very weak and would bog really bad and kill it again, not spitting or sputtering just bogging all the way down using it even doing very minor stuff.. Found a torn servo valve wire and that fixed it.. Ran great then all day like i said and unfortunatly the excavator burnt to the ground when i hydraulic line busted by the engine compartment
OMG you weren't kidding! Hope it was insured or you didn't have too much in it. Well at least you solved the problem you were having. What did the servo valve do/control?
Yeah i wasnt kidding.. unfortunately no insurance cause we werent using it but here and there since we have had it, but the last two weeks we have been clearing alot of our land and lacked about two more days having it finished.. Around 32k in it.. Makes me sick to even see it now.. The servo valve pretty much flows the hydraulic fluid in the direction or loop it needs to flow, it is an electric valve. Thats the reason it was bogging bad when using the hydraulics, but when not using them, it purred like a kitten
Jeez...I better call the agent and cover mine. Sorry to hear about that. And I thought I was having problems!
Yeah you better do that.. Ive been back down there twice since it burnt and i havent messed with it, makes me sick just seeing it there