Posting for a friend who doesn't do computers. He needs your help! He has a 98 953C track loader. When they start moving the loader starts jerking. It has been at the Cat shop which didn't fix it and they have been out to the job site and worked on it with there trusty laptop with no resolution except keep adding parts that don't fix the problem. To date he has added the following sensors: Trans Sensor Speed sensor on flywheel High speed solenoid for left track. Pedal sensors. Is changing the position sensor tomorrow morning! At first the jerking started and a buzzer went off on the dash. He took it to the Cat dealer and they changed the pedal sensors and recalibrated and said the problem was fixed. This was not the case. After they worked on it in the shop it has not showed any codes. Just when you move it starts jerking. The other hydraulics works fine during this and it does it at high and low rpm. The cat tech is now saying possibly a wiring harness??? I have another friend who suggested it may be due to a clogged transmission fluid filter. We may change that tomorrow as well. Right now the Cat ppl are no help and just guessing while we throw money and parts that are apparantly not the problem. Any ideas?? :beatsme I have looked through this forum and see alot of problems with the loaders just stopping but none where it jerks like its coming out of gear or something. Its hydrostatic so that isn't the case. Thanks for your help. Jonathan
How jerky is it? What kinda noise is there? Does it smooth out? Does it do it in reverse? what are the codes? Does it do it in both rabbit and turtle? Does it track straight? Were all the stationary and moving calibrations done? these are good for troubleshooting because it will fail calibration if out of spec. What is the charge pressure? Change the filters and then cut them open and inspect them for debris.
Thanks for your quick response. The jerking is basically like you are slamming it between stop and go but not moving the controls. Jonathan
we have a 943 that was jerky when you started out after lunch and it got horrible. our mechanic jacked up the cab and on top of the hydrosat there is what looks like a valve cover. take that off and there are 4-6 little hydro lines that were loose and leaking in the case so you couldn't see it out side. i think he just tighten them up or put o rings in them and helped alot. later he had to put some kind little pump or valve in there. we thought the hydrosat was out of it, and before we got it fixed we bought a 953b then we finally found it. if the first doesn't fix it tell me and i will ask the mechanic what he did
lgammon did it jerk all the time after that or was it intermittent? Thanks, Jonathan
Originally Posted by Lee-online How jerky is it? Its too jerky to operate.What kinda noise is there? no noise Does it smooth out? It will smooth out but comes and goes frequently. Does it do it in reverse? Yes what are the codes? no codes as far as we know from the cat tech Does it do it in both rabbit and turtle? yes Does it track straight? Yes Were all the stationary and moving calibrations done? Yes these are good for troubleshooting because it will fail calibration if out of spec. What is the charge pressure? He will find out today . He said the machine bucks like a horse. It can run fine for a couple hours and then all of a sudden it starts bucking. He also said he thinks since the Cat Tech has worked on it its getting worse instead of better. I am going to try and video the bucking so you can see what its doing. Thanks, Jonathan
First, the B and C are two totally different machines. You can pull the codes by pressing the bottom of the rocker switch on the dash, the second from the left. This changes from hours to a tach to charge pressure to codes. If you have an active code, the SERV CODE will be lit at the end of the LCD screen. You can also get the codes and clear them with the switches under the right arm rest. Do you know how to use those. do any of the warning light light up? It does sound like and electrical problem, maybe a rubbed harness. Check the harness in the right side access door, where it routs around the air cleaner. i have seen a few rubbed through there. Is this a 2ZN machine?
it was intermittent some times it would start and you could not work with it and would have to quit for the day, and sometimes it would be fine all day. most noticeably when you went to lunch and came back it would kind of go crazy sometimes. it was a bad problem when you had to unload it off a trailer. i know that the b and the c are different but the hydros surely still have a lot in common.
I did find two codes today. One was 030, I left my papaer at the loader with the other code.!!:Banghead Both where dealing with charge system I think. We put the new position sensor on and fixed the harness and he ran it for about 30 min with no problems. Hopefully that got it but we will see. We are going to change the fluid and filters today. I checked the charge pressure and it stayed around 248 KpA. The cat tech said it should be at 360 so I am not sure what to make of this. He said it had a bypass that opened while it was closed so maybe its staying open I don't know. We will check it again after the fluid change and when we run it enough to get really heated up. Jonathan
Where is the cheapest place to get a manual/parts list for a 98 model machine?
The correct pressure setting of the charge relief valve is 2850 ± 50 kPa (415 ± 7 psi). are you sure there wasn't a 0 at the end of the 248. Also, this is with warm oil at high idle with the direction lever in park.
Yes 248 was correct. That was at max rpm. At idle it was showing 138. He ran it for about 30 minutes and checked it again. He called the cat tech and he said 360 was where it should be.:beatsme Thats a big difference! The machine shouldn't move at that low pressure I wouldn't think. Thats what the screen said. Can it be programmed to read without the last zero? Can you tell us how to reset the codes using the switches on the right side of the seat? Thanks, Jonathan
Most read out in KPA but i think they can be changed to read psi. It will show what it is reading on the lcd screen. Was it kpa or psi. If its in psi, i bet this is the reason why its acting up. it just a matter of finding why. Charge relief, charge pump or drive pumps and motor are worn out, failing. If its kpa then the machine would not move at all. I use the sensor for reference but if i have a problem i alway snap a gage on to verify it because the sensor do fail or read wrong. next post will explain how to access service modes.
It was reading in KPA. Will dig into this a little deeper tomorrow. Thanks for your help.
Switches are..... Left ------middle------ Right Service----- Clear------- Calibrate Press and hold the "SERVICE" switch and the "CLEAR" switch. Release the switches while the mode number "-3-" is shown on the display. The codes are here. If there are no codes it will show --- In order to view all the diagnostic codes, scroll through the diagnostic codes. In order to scroll through the diagnostic codes, press and hold the SERVICE switch. Release the switch when on the desired code. The display momentarily shows MID, CID and FMI for each diagnostic code. The word "End" is shown after the last diagnostic code in the list. Codes will look like 079 681F02 To clear the code, hold the CLEAR switch on the code you want to clear. If SERV CODE is show, it is an active code and connote be cleared until the problem is fixed. To exit, press and hold the "SERVICE" switch and "CLEAR" switch. Release the switches when the display is showing normal information (hour meter). Or turn off the key. Mode -4- is tattle tail and will show all the warnings and maximum gage readings since it was last reset. To reset use the clear switch. Mode -5- is calibrations and you shouldn't mess with it unless you know what you are doing.
Thanks Lee! I went back and double checked the pressure and it was 248 kPa. They are suppose to change the fluid and filters this weekend so we will see what the filters look like and see if the pressure changes. I think the gauge must be messed up. We fixed the harness where it was wearing. He ran it for about 30 minutes with no problem so hopefully it was either that or the last sensor he put on. Fingers crossed!! Thanks for all your help. I will let you know how it goes.
I am just joining the forum and learning how to use it. But I just bought a 1999 953C with 5400 hrs. I know very little about it and will get it to our shop to go over and service the machine. Any advice on what to look over and do would be very appreciated. Thanks