Cat 980H bucket dropping

[fmatemberere]

Please help, our Cat 980H serial number AKZL01012 is dropping the bucket when moving with load in the bucket.This is only happening when moving and it’s not doing this all the time.

Thank you

 

[Nige]

First suggestions

1. Recalibrate the lift/tilt control lever position sensors.

2. Recalibrate the linkage position sensors.

3. Recalibrate the proportional solenoid valves for lift & tilt.

 

[fmatemberere]

Thank you very much Nige, I managed to recalibrate the lift and tilt control lever position sensors but the ET is not letting me recalibrate the linkage position sensors and the proportional solenoid valves . Do I need a special programme on my ET to be able to do the calibrations please.

 

[Nige]

First the linkage sensors, because without them calibrated the proportional solenoids can’t be calibrated. Any Diagnostic Codes on them.?

What version of ET are you using.?

 

[fmatemberere]

Thank you, I managed to recalibrate everything mentioned earlier but the problem is still there. The only active code is for the Emergency Stop not working. The other logged event code is 149-5 for Ride Control 3 way Solenoid which occurred 49hrs ago and E350 (1) for Tilt linkage movement and it occurred 85 hours ago. The green Ride Control Light is coming on when the bucket is dropping.

Thank you

 

[Nige]

If the ride control light is coming on when the problem occurs it may be you have a problem with the ride control switch or the RC valve.

I’ll send you the procedure for the 149-5 diagnostic. It might pay you to do it even though the code is not active right now.

 

[Nige]

Here's the procedure. Note the comment regarding electrical connections being clean and tight. Because the Ride Control is integrated into to the bucket lift hydraulic circuit I strongly suspect you could have a bad connection or a frayed wire somewhere in the Ride Control electrical circuit.

Also it might be worth your while to check the precharge pressure in the Ride Control accumulator.

 

[fmatemberere]

Thank you very much Nige, I did not get any chance to work on this Loader today but hopefully I will be on it Monday. I follow this diagnostic procedure you sent me.

Thank you

 

[Nige]

Thank you very much Nige, I did not get any chance to work on this Loader today but hopefully I will be on it Monday. I follow this diagnostic procedure you sent me.

The problem in trying to follow the procedure is that it will lead you nowhere unless the 149-5 Code is Active at the time you do the diagnostic. Based on what you said earlier the Code is Logged, not Active.

I would suggest that you need to examine every electrical connector in the wiring harnesses right from the switch to the Ride Control Solenoid #2.
Also check the Ride Control On/Off switch carefully.
I'll send you a copy of the Electrical Schematic just in case you don't have it.
Including the connector to the Ride Control Solenoid and the one on the ECM there are a total of four harness connectors in that circuit.

Also check the resistance of the solenoid coil. It should be 8.7 ± 0.4 ohms

 

[Per Eriksson]

I assume it's the lift cylinders that are dropping?
Does the drop occur at a certain speed? Normal activation is @ 6mph + activation delay
Which light is on, manual mode or automatic mode?
Do you have the ride control switch on, off or in service mode?
any change in behaviour between the three modes?

If you lift the front tires off the ground with the bucket and turn on service mode, does it drop after 2-3 seconds?
if you run it in service mode, does it have a bounce or is the lift cylinders fixed?

 

[fmatemberere]

Thank you very much guys for all the information. Unfortunately I couldn’t do anything on the machine because when I came back from my off days another fitter had already removed the lift and tilt cylinders for resealing. I will update you when the cylinders are fitted back if the problem is solved.

Thank you