My HT affectionately named "Two Bits" has three other operators. Often I find things are not taken seriously by our mechanics at the shop. Differential cracks on the final drive side spraying fluid on the outside wall of #5 tire. Having reported three times, and taking photos, still I am told "Run it". For the past 6 months I have reported the first stage warning lights on the VIMS panel: Data Link Err. Still nothing is done. Recently she experienced a Break Over stroke. Said it was operator error on the previous crew. Is this truly operator error or something else like worn parts?
Brake overstroke is a Level 3 VIMS Event and is an immediate "stop the machine". Apart from that as an operator you can't cancel it no matter how many times you press the OK button and that constantly sounding alarm is a PITA. Brake overstrokes can be caused by any of the following AFAIK:- 1. Air in the brake oil system. 2. A slack adjuster not working correctly. 3. Brake pack wear to a point that the slack adjuster can no longer cope with it. 4. Incorrect operation by pumping the service brake pedal repeatedly without giving the slack adjuster time to reset after each pedal cycle. Eventually this can potentially overstroke one or more of the brake cylinders. Come to your own conclusions why an operator would do this. First thing to determine in the case of a brake overstroke is which master cylinder set the alarm. There are four, two for the front brakes and two for the rears. The alarm does not indicate which cylinder it was, simply that it was at least one of them and could have been multiple ones. You find that out by diving underneath and check if the little pin #9 that operates the overstroke switch has popped out. These pins do not reset by themselves, they have to be pushed back manually and then the key has to be cycled to clear the VIMS Event.
I am having a real hard time getting my head around the idea that you work for a company that is large enough to be running a 130 ton haul truck and have a maintenance shop that doesn't care about differential cracks and a possibly fatal brake error. Where do you work? I am assuming a mine, but the most "fly by night" mine I ever worked at would never allow that level of exposure to liability. And that place let me ( a paid college intern) once design a blast sequence that would pile up the blasted material to spell my name when viewed from the top of the pit. I will admit that they did not invite me back the next summer.
It's actually a 250-ton haul truck. I'm thinking it's probably a Duo-Cone seal oil leak rather than a differential housing crack and if I had a $10 bill for every operator I've seen create a brake overstroke event just to get a half hour with his feet up until the field mechanics got out there to check the machine out I'd be rich.......
Yeah, I should have checked that before I posted. Honestly, this afternoon I was talking to someone about cat haul trucks and numbering and even then I couldn't remember what the payload vs equipment number was. Been a really long time since I was either an operator or a trainer. And I think the biggest haul truck I have seen since being in Hawaii is a 773. I agree that a differential crack seemed a little unlikely. You could just about walk under a 793 diff without ducking. I know that isn't true. But at the same time..."What the hell did you hit?".
An ex-work colleague of mine always opined that "If you can't walk underneath it it's not worth working on."
that my saying