Working under Diesel Pusher........advice

[Mr_D]

Originally Posted by Gary RVRoamer

mechanical jack stands capable of handling my 20,0000 lb rear axle weight don't come cheap.

I'm trying to find some as our front and drive axles are rated for 20,000#'s and the tag for an add'l 14,000. Right now we're at probably 50,000 total and we're not fully loaded. I'd probably be OK with 4 12,000 stands on the rear and two on the front.
We only have air leveling and I need to replace the rear shocks and I'm not sure I want to trust just the air system for me to be under there. I'll have to take a good look at it tomorrow when I back it out.

[BFlinn181]

I use jack stands, my leveling jacks to raise it up, but also have a 12 ton bottle jack if needed. The other thing I've done is park one side up on a curb to leave room underneath or once I straddled a shallow ditch to leave room to work underneath. Not as good as a pit, but it works. The places to be careful are if you're working on the air lines and put hands up in tight spots. I like the jack stands to prevent surprises in those cases. I did my shocks and had no issues. Lowering the coach as low as it goes, the only spot that could be tight underneath would be at the side skirt and compartment areas. In the middle, between the frame rails you can almost sit up when on the stands.

[ShapeShifter]

Originally Posted by slickest1

If the air started to go while under there I dont know if I could get out before it got too low for me not to get out.

You can't. Never get under a coach that is supported by the air bags or the leveling jacks. If you are working under there, and happen to nick/cut/damage or accidentally disconnect an air line or hydraulic line, the coach can come down fast. Your body will not support the weight of the coach!

You can use your leveling jacks to raise the coach to place quality jack stands with sufficient rating under the frame, or build cribbing under the frame. But before going under, retract the leveling jacks and deflate the air bags.

You can also build ramps under the wheels, as already described, but make sure to dump the air bags before getting under. If that makes it too low, you need taller ramps.

But any jack stand/cribbing/ramps needs to be very sturdy: a few old 2x4s won't cut it! Also, make sure the ground under the coach and supports is solid, you don't want the supports sinking into soft ground or working their way into gravel. And NEVER use concrete block (cinder blocks) as any part of the support structure, they can crumble far too easily.

Getting under an improperly supported car can kill you if it falls. But a motorhome is far heavier, making it more likely to fall, and making the consequences worse. And unlike a car, with it's spring suspension, both the air bags and hydraulic jacks are susceptible to sudden failure. The only saving grace is that if the motorhome falls on you, death is likely to be quick and you won't suffer long.

[BennieH]

Built my own ramps as well. 12" high, plenty of room to do what I need to do. Good price on the 12 ton stands, gonna put 2 sets in the budget. Can't be too safe and you don't get a mulligan.

[palehorse89]

Originally Posted by DGBPokes

Never have liked working under things, but have done it many times with cars and previous gasser motor homes. New to us is our 07 Kountry Star. 3912 DP.
I have yet to get under it. It is low when air is dumped and jacks are down. Do I work under it with air bags full and no jacks. The street in front of the house is sloped such that to level the rig the nose is down, the rear is up, and the starboard side, next to the curb is up.
I am not sure if I can even slide under the front.

The simplest thing to do is with the Coach's bags aired up at ride height, put big blocking of some kind(I have 12x12x12") under the jack pads, and then shim with smaller to make the blocking within 1" or so of the jack pads, now you can raise it a bit if needed and it can only lower to the ride height if the jacks fail, I can work under mine at the ride height. No jack stands needed, as the Coach's jacks can only go to the retracted position, which will still be at the ride height, and if the bags fail, it will still sit on the blocking at the ride height.

[POPPASMURF]

I can tell you one thing that didn't work for me. I used a 5 ton hydraulic jack to raise the rear body under the hitch a couple of inches. Just as I was ready to slide under the self leveling did it's job and the back end of the MH squatted down-nearly destroying the jack. I will use solid wood ramps but be careful if the self levelling gets involved- even then it could defeat your best efforts.

[BFlinn181]

Originally Posted by POPPASMURF

I can tell you one thing that didn't work for me. I used a 5 ton hydraulic jack to raise the rear body under the hitch a couple of inches. Just as I was ready to slide under the self leveling did it's job and the back end of the MH squatted down-nearly destroying the jack. I will use solid wood ramps but be careful if the self levelling gets involved- even then it could defeat your best efforts.

When you say, "self leveling" are you talking about ride height or your leveling jacks?? I don't really understand. Putting a jack under the hitch, in the center, at the very end of the rear body, furthest from the rear axle I'd expect you were trying to lift far more than 10,000 lbs. What's the rating for your rear axle?

[ShapeShifter]

Originally Posted by POPPASMURF

Just as I was ready to slide under the self leveling did it's job and the back end of the MH squatted down-nearly destroying the jack.

I doubt self-leveling had anything to do with it. It's MUCH more likely that the seriously overloaded 5 ton jack simply failed under the weight. If you were jacking up the rear axle, your jack would be trying to lift double it's rated weight. Being back by the rear hitch, it was trying to lift even more weight. You were simply asking that poor jack to do way too much lifting!

[cbeierl]

Originally Posted by Old Car Nut

Not all that bad Amazon.com: Torin T41202 12 Ton Jack Stands (Sold in Pairs): Automotive

IMPORTANT: Be aware that jack stands are rated in pairs--therefore each of the above jack stands can support 6 tons max.

[POPPASMURF]

Uh-if you read my post-I was jacking under the hitch. I was looking for about 2 to 3 inches more- and it WAS the self levelling-and yes it definitely overcome the capacity of the jack. I won't go under now unless I can place supports of rated capacity, no matter if using ramp or just quick skuttle under at rest.

[ShapeShifter]

Originally Posted by POPPASMURF

Uh-if you read my post-I was jacking under the hitch.

Yes, that was clear, and I don't see where anyone was questioning that?

Are you referring to my "If you were jacking under the axle" comment? If so, I was just using that to say it would've been bad enough to jack there, and worse because you were jacking under the hitch.

and it WAS the self levelling

So far, nobody that has responded to you knows what "self leveling" is, so what is it?. Are you talking about the ride height control valves letting air out of the air bags because they think the back end of the coach is now too high? Did you have automatic air leveling enabled? Was it something to do with hydraulic leveling jacks? "Self leveling" is not a commonly used term for motorhomes and we don't understand exactly what you mean.

But either way, if there is a system that is trying to maintain level, and you artificially raise the back end, it should be no surprise that the system will react to try and lower the coach. This means that even if the suspension or leveling system was supporting the weight of the coach, as soon as you lift it too high, it will try to lower the coach, leaving you to support the full weight of the coach.

I won't go under now unless I can place supports of rated capacity, no matter if using ramp or just quick skuttle under at rest.

Very wise. It's been stated before (even in this thread) that you should never get under the coach unless it is firmly held up by adequate supports, and you should never rely on any part of the air suspension or hydraulic leveling jacks to provide any support. You must be able to fit under the coach with the leveling jacks fully retracted, and the air bags completely dumped, because either of them can suddenly drop the coach on you at any time - don't trust your life to them because they were not designed as a robust safety system: they have too many single points of failure that can bring the coach crashing down on you.