Cribbing for larger trucks

[dzzz]

I've been looking at best practices for cribbing jacks and jack stands on larger trucks. Here's a post from a firefighter forum with a good link. Some people advocate softwoods over hardwood due to characteristics at the point of failure.

I think 24" 4x4 doug fir works best for me. Enough for a hydraulic jack and a jack stand.

 

[alaskaboy]

re cribbing

Good to know.

Are you planning on a conventional bottle jack on the top platform for your mog? That would not be an insignificant volume of crib materials to carry (8 to 10 sticks of 4x4?).

 

[dzzz]

That's the plan. It seems to me to be the safe way to approach lifting a tire or axle without a $3000 airbag. But I'm open to suggestions.
I figure on cribbing and jacks taking up about four cu. feet.

 

[grizzlyj]

Hi

Stupid question, what do you use this for? Extra safety when up on a jack?

Jason

 

[alaskaboy]

The vehicle in question has largish tires in the 42-46 inch range plus portal axles. Thus, the average stroke on a bottle jack would never reach a lifting point, not to mention would have severe stability issues if it did. You gotta bring the ground up to the truck as it were.:ylsmoke:

 

[dzzz]

46" tires which puts the axle at 20".

A bottle jack doesn't have enough lift range considering 12-13" of sidewall. An airbag is probably the best choice as it can be operated beside the truck.

I can use a farm jack, but that's with me under the truck.

 

[LukeH]

46" tires which puts the axle at 20".

More; the Mog's axle isn't in line with the centre of the wheel.

What makes life even worse is that you could probably lift the bodywork of a MOG (assuming there's a jacking point strong enough) the FULL height of a farm jack and not get the wheel off the ground.
The'yre designed to keep wheels down in some pretty extreme twists...

Hmm; quite a challenge

 

[mhiscox]

When I had Camper Mog (16K pounds), I carried two bottle jacks, one for the heavier straight axle rear and one with higher stroke for higher portal axle front, along with an assortment of plastic cribbing blocks which I got from here or someplace like it (it's been eight plus years; don't quite remember):

http://www.florawrecker.com/store/PLASTICCRIBBING.html

Scrap wood is cheaper, to be sure, but this stuff was splinterproof, easy to keep clean, etc., so it might be worthwhile to some.

 

[Tennmogger]

I carry a 20 ton bottle jack and 6 pieces of 4" x 12" x 18" pieces of cribbing. Two layed flat then a third crossways makes the right height (4" + 4") for my bottle jack under the U-1300 axle. The other pieces are used mostly to level the truck with the camper.

One trick to use a Hi-Lift jack on a Unimog: chain the axle to the frame above it. Lift the frame and let the frame lift the axle. That way the axle can't sag.

Bob

 

[dzzz]

...............

One trick to use a Hi-Lift jack on a Unimog: chain the axle to the frame above it. Lift the frame and let the frame lift the axle. That way the axle can't sag.

Bob

Unfortunately the heaviest hi-lift jack I can find is 4 ton. I really should have twice that.

What tire size do you have on your 1300L?

 

[Tennmogger]

Unfortunately the heaviest hi-lift jack I can find is 4 ton. I really should have twice that.

What tire size do you have on your 1300L?

14.5 x 20 Continental E6's at the present time. Going back to Michelin XL's as soon as I get good weather and a better attitude to break down and remount all those tires!

My axles each carry 7000 lbs, within a couple of hundred lbs. Half that, 3500, is well within the capability of a Hi-Lift, especially if it's sitting on a stack of cribbing so the lift does not use the top end of the beam. Your truck must be heavier?

Bob

 

[jesusgatos]

What makes life even worse is that you could probably lift the bodywork of a MOG (assuming there's a jacking point strong enough) the FULL height of a farm jack and not get the wheel off the ground.
The'yre designed to keep wheels down in some pretty extreme twists...

Hmm; quite a challenge

Lots of people use different types of cables/straps to connect the axle to the chassis prior to lifting. Simple and effective, especially on long-travel desert trucks and other performance-oriented off-road vehicles.

 

[dzzz]

The truck's about 12 tons, so I need at least a 8 ton jack. I don't believe jacking from the frame is done on a truck this size and height. It's either the axle or suspension piece.
I do have the longer hi-lift jack, but don't intend to use it on this truck. This is the longest lift regular bottle jack I could find:
http://www.northerntool.com/shop/tools/product_200305495_200305495
And a long ram jack that might work for higher/longer lifts:
http://www.harborfreight.com/8-ton-super-heavy-duty-long-ram-hydraulic-flat-bottom-jack-36469.html
The long ram is somewhat too long at 24" closed
A 20" closed, 16" lift would be about ideal.

 

[burquedoka]

If a bottle jack is all your after, call one of the Mog parts dudes and order the factory intended unit.
As far as cribbing goes, I have been in the fire service for over ten years now and all we used, until recently, for cribbing is 4x4x24's. They are more than sufficient to create an elevated surface. This should be the first choice of operation when jacking a mog on non hard or uneven surface, it's just good safe practice. A nice detail when dealing with handling of cribbing, wether wood or composite, is to slip a loop of rope through a hole drilled through an end corner to use as a handle. Then they can be loaded vertically in a bin and still be able to be pulled out quickly, and with out dumping the whole quiver out.

 

[grizzlyj]

Hi Don

I'm not sure if the link below is your posting? But some pics of my 10000kg Mog jack lifting my 9.5ton U1700 with 395s. Floor to axle tube is about the same as the jack fully extended, so broadly speaking the thickness of the bearer on flat firm ground is how much free space you get under the tyre at this size. Extends about 16" to 27". Which is why I was wondering about the need for so much timber

http://www.benzworld.org/forums/unimog/1569537-jack-u500.html

Am I right in remembering the maximum capacity for Hi-Lifts etc is actually only within the first foot of rack, so although one might do something to a Mog bumper, I wouldn't think its too safe!?

This forum doesn't seem to like the upload of the rest of the pics, even if within the limits stated for upload. I'll try again if anyone wants and resize them even smaller

Jason