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extreme braking: keeping a loaded dump-truck from rolling...

808pants

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In doing some excavation on my steep hillside property, the only feasible place on my cramped steep sloping site to load my 5-ton has been on a dirt-and-gravel temporary driveway that runs sharply up from the narrow street below. With the truck backed up the driveway to amply clear the road below, I would run my loader from the excavation area above all of this, down the upper part of the driveway, and then let the load spill into the truck from the back. After a few loads it would get to the point where the loose material was reachable over the tailgate. From that point, I could use subsequent loads to shove on the whole thing, to pack the soil towards the front of the truck with each new load. Now, shoving new soil into a heavily-loaded dump truck that's pointed down my driveway, basically in line with my neighbor's front door, was never a favorite thing to do, but I'd always have the wheels curbed sharply into the hill, transmission in reverse, and handbrake set to the extreme. The truck never budged.

Until one day... I was confidently packing one of the last loads of soil onto the back of the bed, when the truck lurched forwards, and then stopped. And then repeated this. The lurching must have been from the load actually turning the engine over in reverse, as each cylinder reached a backwards compression peak and then 'went over the hump,' so to speak. The downhill lurches continued as I scrambled out of the loader, thinking I had better get in the truck and be ready to use air-assist brakes ASAP - but I knew that the air would take some time to build up and make the brakes useful. It was only then that I saw that a lazy tenant of a neighbor had parked his vehicle right in front of my lurching soil-laden truck. I was screaming at the top of my lungs for him to get out there and move it - before my M51 came down on his hatchback and crushed it in slow-mo - while I wildly heaved on huge rocks nearby in an adrenaline-fueled attempt to chock the wheels before this played out. Fortunately, he heard me and got up to the street in time to get his vehicle away, and by then I had wrestled a huge rock in under the front wheel, which seemed to stop the lurching and let me catch a breath.

I think this terrifying slippage had to do with the extra weight of rain-soaked soil, but I also later noticed that the handbrake drum happened to be situated right below a leak from the rusty dump bed, and it looked like a rivulet had fully soaked the drum and shoes with muddy rainwater from my soil load.

That was a bit more adventure than I care for in this excavation endeavor, and was a few years ago now. But since I have plans to do more of this work at some point, I am wondering if there are any bulletproof methods to absolutely stop a 5-ton from moving downslope (other than maybe sliding on locked-up tires, which no one could hope to do much about.) My temp driveway is too steep and irregular for anything like standard rubber wheel-chocks to do the trick - they'd just get run over unless they were gigantic, I think.

I was thinking about somehow using a load-binder and chain to join the two rear wheels at their closest approach, for example...or maybe secure one to the bed itself...but I would hope for a lighter-weight and less crude, potentially muddy method. A hydraulic line-lock, maybe...but not sure I trust the single-circuit brakes for this, either. Anyone?

--Dave
 

rchalmers3

Half a mile from the Broad River
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808,

Have you read the winching TM and seen where a log chained to the bumper acts as a wheel stop for winching? I wonder if that's all you would need to prevent "ghost driving" the truck down hill.

Rick
 

jwaller

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the 816 and 819 wreckers use a line lock. that would do it very well. once set it's not coming off till you release it. I put an air lock on my 818, only works while the truck has air though. so leave it running.
 

cranetruck

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Well told story!
What about good old wheel chocks? If you are alone when leaving, back up and steer to the side of them going back down hill.

Remember Wayne Harris (papercu) in GA, having some big perforated metal ones...
 
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Recovry4x4

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Good advice from the masses. I have a MICO lock on my wrecker and it works great. I leave the truck running so it has adequate air pressure. Lets revisit your parking job though. Was the truck in high range or low when you parked it? Low would provide twice the compression braking as high range. If relying on the park brake and keeping the truck in gear, I would have put it in low range and used first gear. When it was time to leave I would have released the parking brake and started it in gear without the clutch. Youl would have gear reduced compression braking going down the incline. The best failsafe though was the one Rick mentioned, its called a scotch anchor.
 

808pants

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@ Recovry: too long ago to remember whether Hi or Lo range - I suspect I'd made so many runs without incident by then that I'd left it in high-range on that occasion. Good point. Regarding "When it was time to leave I would have released the parking brake and started it in gear without the clutch..." I don't think I get it - wouldn't that give me a wildly lurchy downhill ride as the engine started? (It's a tiny road below, and people tend to slow down in the interest of self-preservation when they see the M51 looming above them on the steep slope - so I try to ease into the road at some fraction of a mph in order to avoid terrorizing any vehicles I might not yet have been able to see).

Bjorn - my "driveway" is really an absurdly narrow rough cut into the hillside, so there's no room to maneuver around chocks without a good possibility of going over the edge (tumbling sideways a few times followed by a Hollywood-style fireball - it's all there in my imagination...) But it sounds like Wayne made some big ones out of... landing mat? I like that idea, but not for my setting.

Rchalmers3 - Where's the TM that covers the "log-on-bumper" method? I'm trying to picture that...

The line-lock method is probably the best for me. At risk of overcomplicating things, I am wondering about augmenting it with some kind of high-pressure line switch, such that if fluid pressure drops to some set point, it will alert me. It seems like I am finding all kinds of real and potential leaks in my brake system, even as I fix the more obvious wet-spot issues. A low-fluid-level alert switch for my remote reservoir is also on my mind...

--Dave
 

Jake0147

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I have a similar but smaller dilema. The "good" spot to load firewood (by hand) on my deuce leaves it in a similar situation. no neighbors, but a hundred yards of STEEP logging road, rutted enough to steer the truck with no operator input, straight to a 15 foot ravine if you don't make the curve at the bottom.
I run a loop of chain through the hand holes on each side of the rear tires. The uphill axle gets it through the lowest hand hole, the downhill tire gets it through the highest hand hole.

A, that's the best "leverage" for the chain to stop the truck should something happen. (Knock on wood, it hasn't yet).
B, if I ever have to back up the hill to release the chain, that's nearly 180 degrees of wheel rotation, so if it slips just a little I should still be able to get both of them "slackened" enough to remove them.
C, if it doesn't want to back up because the road is not as well knit on one side as the other (a real possibility) the chain on the slipping side will catch in the other direction, and allow me to release the other side, then rolling forward allows the release of the remaining side.

This DOES require a "Soldier B", however even working alone (not a firewood trip, not for me...) It's a lot more convenient to find a Soldier B that you don't have than to recover a truck that you used to have from a ravine, or your neighbors car, or heaven forbid your neighbors house.

Brief testing shows that at that 90 degree mark (that is, 90 degrees between the radius from the center of the axle to the hand hole you're using, and the center line of the chain that you're using) the deuce does not have what it takes to damage a wheel or break a 5/16 inch (logging grade) chain that is formed into a continuous loop. That is... One rear side chained, the other side not chained, the front locked in. So two front wheels at the "regular" speed, four rear tires at double the "regular" speed, and four rear wheels at zero. The ride is violent, but the chain and the wheels take it just fine.
In practice I use a 3/8 chain, because I own two that are about the perfect length, but 5/16 log chain does the job. So for your five ton, I don't think you'd need anything spectacular. 3/8 should more than do what's needed. Mechanical advantage is in your favor if you set it up just as I described.
 

Scout

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I have mico-locks on a couple trucks. The newer ones have a switch built in that closes if line pressure drops while the brake is activated. Just run power to the switch and on to your airhorn solenoid - I expect it would handle 24v. If line pressure drops the horn goes off. You can't beat having all 6 wheels locked up - I have a 2-circuit lock on my farm truck for winching.
 

808pants

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@Scout - thanks for the update - haven't used a line-lock since 1980-something...when they were made of granite and switches hadn't been invented. That sounds like the simplest/bestest solution - though my air-tank drains so fast that I'd have to put an all-electric alarm horn or something similar on the truck (to make sure the whole neighborhood knows my truck brakes are out...)

@Jake0147 - I thought I was with you but then I got lost in the last paragraph - references to "regular" speed and "The ride is violent" make me think you're describing actually driving with those binding-chains in place for some reason?? I can't make sense of that, though I too had been thinking of binding the wheels together using chain and maybe a load-binder to tension them, since it seems like the next most reliable thing to using a boulder to stop the truck.
 

tigger

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I have the drive line out of my truck from when it was towed home and i put a chain thru the wheels and it holds just fine but I'm not loaded ether but i think i should work just fine. #1 thing is be safe it is not worth you getting hurt or hurting someone els.
 
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