CAT 312B Problems

[mrh1966]

I purchased a 1998 CAT312b from the US and got it delivered to a private island in the Bahamas. Its a bit beaten up but got a good engine and hydraulics. The problems i have are electronics. The exhaust/muffler was blowing and i managed to get a new one in the UK and take it over with me on one of my visits, also new filters all round to service it. The machine would not start and i thought it was the big solenoid in the compartment by the batteries. Replaced this but still no joy. Before the machine stopped working i lost all the dash lights. When testing the power supplies I found there was no power to the keyswitch. I removed the starter and tested.....all ok......put a separate live from the battery to the key and it started..........no dash light!!!!!!! any ideas as to why the dash lights have stopped working.
The machine is a Cat312b 1998 s/n 9hr02634
thanks in advance for any replies

 

[riland]

I have service manual and parts catalog for you excavator. If need - contact me - sdkmaster@gmail.com

 

[CRAFT]

Hmmmm ! .... you know what ? ..... I hate to be the first one to tell you ..... BUT you still have the problem. Putting in a jumper wire didn't fix a thing..... it only proved that you may not need to play the game of lets buy another part and see if this'll fix it.

You need to find where you have either an open circuit or a dead short.

Find that first before you decide to put another jumper in to get the display to work. With the open circuit that you already have, that jumper wire it will also feed back to where it is open.

 

[mrh1966]

Craft........thanks for your reply........my biggest problem is that I am in the middle of nowhere, limited knowledge resources and problems getting parts/part numbers....it can take up to 2 weeks to fix a puncture on our JCB tyre!!!!!!!!as an example. I have checked all fuses and have tried to chase all the wiring as much as I can to see if there was any breaks. The muffler was blowing for a while which resulted in the melting of the throttle cables.......I have partly stripped these back but are still not working.....so I have made up a manual version by the use of cables which I pull on and tie up to increase/decrease engine revs. The electronic controls/overide at the back of the console still work to a small degree.......I go out there one week in every six to operate this machine and need it running whenever I am out there......as I said I am from the UK.......the machine was purchased in Miami.......and i try and get the parts in the UK.......No record of machine in UK as it is classed as a grey import!!!!!! Just need to know where to start looking........

 

[CRAFT]

............. The muffler was blowing for a while which resulted in the melting of the throttle cables........

............. "BEEN THERE DONE THAT" .............. go figure in the UK they call our machines GREY ....Hmmmmmm ..... WOW ......I always thought the term grey was used for aisan spec built....... never would I have thought that you guys would call ours that..........

If that thing was working one day and not the next time then I would think corrosion ........ohhh ! .... btw.... when you said you put a jumper at the ign switch did you still cycle the key to get it to start ?? ........ I have a weak/worn ign switch in mine but it still is working until I get my butt in gear to change it out ..... Sorry! can't help you out there Chap .... good-luck

 

[Per Eriksson]

So if I got this right, when you supplied the 105red wire at the key it could be started with the key but nothing else worked?

 

[mrh1966]

Yes that is right Per. I ran a direct feed from the battery to the red 105 wire at the key and it started first time.......but still no dash lights........

 

[javid]

grey machine, no prob u should start by checking checking the fuses> main relay> breaker and check for broken wires ,

 

[RobVG]

We have a CU.

It has a battery disconnect switch on the outside of the fuse box. Wouldn't hurt to open the box and test the switch if there is one.

 

[mrh1966]

Thanks javid............I have checked the fuses......all ok.......swopped the relays around....no difference..........by-passed the breakers and checked for broken wire as much as I can and have not found any........
RobVG.........do you mean the one that breaks the earth?.....if so I have by-passed this also........thanks

 

[RobVG]

Now you mention it, it does "break the earth".

It wouldn't have been your problem.

 

[dirtdobber1]

Mrh,

You may already know this, but the two switches on the right hand armrest - the one closest to the operator kills the machine's electronics and puts it in a manual mode. The other switch controls the throttle manually. If the switch closest to the operator is in the manual mode, you will not have any of your displays working. the starter issue may or may not be related to this, though.

 

[mrh1966]

Thanks dirt, yes I do know this......they do not come on when the switch is in either position......which away is normal?....up or down?....the label has worn off!!!...the manual throttle works though...

 

[roughrider]

This is a shot in the dark, but had the switch been messed with prior to the dash going out? ...My thought being that maybe it is as simple as a faulty switch, like when you put your power window down on your old car, the switch goes out, and now your stuck with a window down in the rainy NW. Just a thought.

 

[dirtdobber1]

I don't remember which way is normal, and I won't be back to my machine to look for some time. I'll bet if you solve the starter problem, figuring out the switch position will be real easy.

Have you dropped the covers that are directly under the cab? Lots wires and connections pass through there. I had a rodent nest in this area and chew up some wires once.

 

[mrh1966]

Thanks dirt.............have dropped the covers and all looks fine.........the was signs of rodents in the battery area.........have checked all wiring there and its all ok.............the lights went out mid operations thats why I think the switch had not been touched.....also it started a couple of times with the lights out......I put a new muffler on and started the machine..........it ran for about 15 mins the stopped on its own......the rest is written in the threads above....started with a live feed straight to the key

 

[rudeag]

MRH,
If you are still on the forum did you ever figure out the problem? I have a very similar mess.

 

[mrh1966]

Hi rudeag...........still not figured it out but when i remove the display there was a grey box at the bottom of the housing, where all the air pipes are. There was a number of wires corroded from the box. I don't think this box was shown on the Electrical Diagram that I was given.......so sort of gave up on it as the machine was running fine without the dash working!!!More problems now as track adjuster will not take grease to pump up the tracks.......Threw a track again!!!! last time I was out there, June '13 so have got new seals and new grease nipple and i am going out in the next couple of weeks to spent the week repairing this machine. Have sent out a pallet from the UK with:-Hydraulic Radiator (mine is leaking), Throttle cable, New sprockets, upper rollers and 6 new bottom rollers. Also got a couple of rear engine compartment doors as one has been ripped off and the other is bashed up a bit.
I have been told they are more of a mechanical engine ,so not much computers to make it work. As mentioned, on a private island ,20 mins flight from Nassau, and a 10 min boat ride to island.......very hard to get parts ,help etc....this forum and all its members have been great so I am sure someone will be able to help you out more..........cheers

 

[trackdoc]

That sounds like a nice place to be going as I'm sitting here in -30.
Be prepared to take out broken bottom roller bolts ie have a drill good bits and some method of welding

 

[CRAFT]

…………………...More problems now as track adjuster will not take grease to pump up the tracks.......Threw a track again!!!! last time I was out there, June '13 so have got new seals and new grease nipple ………………….Throttle cable, New sprockets, upper rollers and 6 new bottom rollers ……………..

Had to put in a new throttle cable a few yrs ago, it wasn't worn but melted because there is an plug on the bottom of the muffler that rotted out (did not know this as it is not in an obvious or visible place) … so it seized the cables in turn frying the throttle actuator motor …….. have replaced the top and bottom rollers, they dried up and … well that's just the way it goes ……… But now I have to deal with the track tensioners !!!! ……

I'll bet You a "Buck & a Coffee" that your adjusters are NOT the main problem ……. Have a Look at how far the Idlers are in proportion to the sliding track that they travel in, if the front part of the Idler Carriage is showing flush with the front of the Car Body, then i'm betting that you are extended as far out as they will travel …. The next thing that happened to mine was after really looking close I seen that the Caging rods that keep the springs compressed, the double Nuts either are ready to break or broken off …….your Rails/chains are worn enough that the track may look like it's still in good shape (As Mine Do !!!) BUT if you look really close you'll find that the Pins and bushings are probably Shot (F'd-Up) ……. I looked at shortening the rails to get the Idlers back in closer, Then I found a couple of broken bushings and where the pins actually wore into the links ……… "I TOO" have been fighting the trowing Track problem, sometimes 3 times a day (we had it down to 5 mins back on) ……………. So now i've given up on fixing the S**T and will be buying a complete set of tracks or just the rails and 2-pails of Pad bolt & nuts + I have to repair the adjuster rods and re-seal the hyd tensioners ….. ~$10-$15,000.000 CAD …. the 312 is worth it as it's sitting at 5400 hrs on the clock …….

mrh, just thought i'd point this out to you before you find you wasted time and money to fix what might be still broken after your planed repair !! ….. Cheers