HM400 Box Control

[John C.]

I got a call this morning from a friend troubled about a scary occurrence on his HM400-1 articulated haul truck. It seems a couple of weeks ago his operator was on a haul when the box started going up on its own. People saw it going up and through a lot of wild gestures and such, got the operator to stop the truck. He shut the engine down to stop the box, started it back up and the control worked fine. My caller was on another site yesterday where there were other trucks operating and he mentioned his story and they told him it happed to them as well on one of their machines. Apparently it has happened a number of times on their machine so they shut it down.

Apparently the control at the handle is electrically operated and we don't yet know if it is just switches or it runs through a controller. I suspect a controller because it also has a transmission function and an engine start function to go along with float, hold, up and power down.

Any information would be greatly appreciated to say the least.

 

[skyking1]

I wonder if they could pull the breaker or somesuch to keep going until you figured it out?

 

[John C.]

Its got a control box that the lever hooks to and it is mounted behind the seat and a pain to get at. I'm not on the job for the problem. My friend just wants to know if anyone else has had the issue. Two similar machines in a relatively small area tends to make the hair stand up on the back of your neck when something like this happens.

 

[excavator]

Hey John, I think I have a PDF shop manual if you don't have one.

 

[John C.]

Thanks excavator. Right now it isn't my job but I appreciate the offer on the book. I'll let you know if I get sucked into this more.

Much Appreciate the offer!

 

[junkfixer]

Believe or not, just had this issue on a HM400-2. Found the issue in the electronic pilot control. It is mounted on side of the hydraulic tank. Can't say for sure the HM400-1 is the same. I believe there is a switch in that dump handle but can't remember if it can be purchased separately.

 

[skyking1]

I saw an HM400 on a Hos Brothers lowboy today. I wonder if it is the problem truck?

 

[John C.]

It might be a trade in or just going to another job. The subject truck is working down at Washington Quarry.

I've been looking at Hos Bros. stuff for years. They likely would have put it in Modern's shop after the second time it happened.

 

[skyking1]

I had the mini behind the dump truck and he went by while I was fueling at the Canyon Pacific Pride. Lots of going's on with the Formark slash pile burning, etc.

 

[John C.]

Where is that happening at? I didn't know that burning slash was allowed over here any more.

 

[skyking1]

Where is that happening at? I didn't know that burning slash was allowed over here any more.

It was spontaneous combustion, not a planned burn. They were fighting it with their own water truck when I saw it. it was a slash pile at the west end where they stuff the containers with logs, there at the end of Canyon Road.