Landing gear

Jim Blackwood · September 16, 2020, 08:18:19 AM

Went to TMI yesterday to find some leveling jacks. JOST makes a nice one, has a 10x10 fixed foot and is just under 30" tall with 17" of travel for $290. They also make a 19" version. I'm thinking they may just be able to bolt directly to the bay bulkheads. I'm thinking one 17" centered in the front and two 19's in the corners of the rear bay. Thoughts?

Jim

Jim Blackwood · September 16, 2020, 12:38:49 PM

Here are the rear jacks in place but not bolted up. I think they will work fine.

Jim Blackwood · September 16, 2020, 12:42:42 PM

The one on the bench has the cushion foot removed so I can install it in the front. I think I can use bolts to reattach it instead of welding. The last shot is of a gearbox I am going to try, it has about a 100:1 ratio. I have a 1/2hp 110v motor that will bolt to it. It draws about 780 watts so one of my 900 watt inverters should power it OK.

Incidentally, the bay floors of these is aluminum, not stainless.

Jim

Utahclaimjumper · September 16, 2020, 01:04:42 PM

These are obviously mechanical jacks and not hydraulic.. I'm assuming they will be powered by three separate motors and controlled individually..>>>Dan
( Very similar to jacks found on a 5th wheel.)

uncle ned · September 16, 2020, 04:32:35 PM

Huggy has 4 hydraulic jack 2 brhind the front wheels and 2 behind the rear.

I was afraid of the 3 i thought the one in front might rock when getting in and out.

been that way for close to 20 years still works good.

uncle ned

Jim Blackwood · September 19, 2020, 11:05:55 AM

Here are some more shots. After studying the problem of mounting and looking at material costs I've decided that a truss type mount makes the most sense and I'm leaning towards a build up using 1/4" x 1 and 2" strap and a bit of 1 x 2" rectangular tubing.

As you can see from the last shot the bottom will have to be reinforced where the jack went through the center rub rail but that should be no real challenge. The load should be balanced fairly evenly between the 3 legs with perhaps a bit more on the rear. If you've never owned a tripod rig you can take it from me that they are easy to level and stable. The extra width between the rear jacks will insure that. As far as tipping it when you climb aboard? Ha! Don't make me laugh.

Jim

Utahclaimjumper · September 19, 2020, 01:05:15 PM

I have the three leg system in my rig,, one in front and two at the rear.. The principal of the three legged system is to raise the front first to allow the frame to "teeter" when leveling laterally,, this prevents frame twisting and minimizes body flexing when leveling on off camber surfaces..>>>Dan

Jriddle · September 19, 2020, 02:14:09 PM

Jim

This looks cool to me.
I'm not sure about your bus but I was drilling into the back bulkhead during my construction. It was more inboard than where your pictures show but I found an air beam back there. It hissed away while I was swearing. When it was done the suspension was down. I got to make the hole bigger so I could weld up my mistake. I'm sure you are ok where you are locating them but thought I would share.

John

hogi6123 · September 19, 2020, 05:23:58 PM

It's my understanding that bus air suspensions are actually a tripod system: one leveling sensor for each side of the rear, and one leveling sensor for the front, with both sides of the front plumbed together.

I expect any solid connection to the ground would be welcome. Just make sure all jack feet are placed on a wide solid footing or they will sink.

richard5933 · September 20, 2020, 04:22:10 AM

Quote from: hogi6123 on September 19, 2020, 05:23:58 PM
It's my understanding that bus air suspensions are actually a tripod system: one leveling sensor for each side of the rear, and one leveling sensor for the front, with both sides of the front plumbed together.

I expect any solid connection to the ground would be welcome. Just make sure all jack feet are placed on a wide solid footing or they will sink.

Yes and no. There are only three height valves, but there are wheels at all four corners.

The two rear valves control the side-to-side height adjustment, and the front valve control the up/down of the nose. But, the front does not have a separate side-to-side control from the rear.

luvrbus · September 20, 2020, 06:12:05 AM

The newer stuff has leveling valves on each corner ,I have the 3 point leveling system on the Trek,the 4 point system on the CC is a lot more stable so was the 4 point system on my Eagle

thomasinnv · September 20, 2020, 08:48:27 AM

Quote from: luvrbus on September 20, 2020, 06:12:05 AM
The newer stuff has leveling valves on each corner ,I have the 3 point leveling system on the Trek,the 4 point system on the CC is a lot more stable so was the 4 point system on my Eagle

Majority of the 4 leg systems are designed to prevent you from twisting. Some of them have both front jacks tied together so that they cannot be operated independantly. Most 4 legged systems are designed so that 2 jacks are always operating in unison, never opposing corners. My air levelling system actually senses twist and will shut the system down if a preset twist limit is reached.

luvrbus · September 20, 2020, 09:12:31 AM

Quote from: thomasinnv on September 20, 2020, 08:48:27 AM
Majority of the 4 leg systems are designed to prevent you from twisting. Some of them have both front jacks tied together so that they cannot be operated independantly. Most 4 legged systems are designed so that 2 jacks are always operating in unison, never opposing corners. My air levelling system actually senses twist and will shut the system down if a preset twist limit is reached.

My HWH Active Air system if the excessive slope light is on it won't even work manually or automatic

Jim Blackwood · September 20, 2020, 09:34:12 AM

I don't think there is any air in the bogies on the 102D series but please correct me if I am wrong. I plan to tie into that part of the framework with a truss that runs across the bulkhead in the rear and one that runs between the front frame members in the front. I should probably plan on using a thread locker anyway and that should seal up any leaks.

Right now I'm preparing my steel order, currently including 3 lengths of 1 x 2 x 3/16 rectangular tube, one 1/4 x 2" strap, one 1/4 x 1" strap, one 1/2 x 1" strap (only need 2 ft but it's handy to have around) and 6ft of 1 x 1 bar.

The rear truss will have three 1 x 2 stringers and the 2" strap full width plus another 1 x 2 across the bottom, the front will have two stringers plus the bottom, both with diagonal bracing via 1" strap. That should be quite stout enough even for the cantilevered load. The bottom of the jack will be tied into the bay floor, at the strong outside corners at the rear and at the floor stringer in front. Btw, the fresh air duct is a 3" flue pipe that runs through the left side of the front bogie frame, that's what the 1/2" strap is for, to build a riser to move the the fiberglass 90 degree duct to the rear where it directs the air up into the return duct.

Incidentally while under the bus I discovered it had been high centered at some point in it's life (almost inexcusable with the rear-lift) and this was why my condenser door was jammed up. I used a high lift jack and a bracing bar to push the outer rail back down so the door would close easier. Still not perfect but much closer and I can probably get it back to normal from here.

I will be making use of the dump valve to lower the front before leveling, and looking to see if there is a valve that can also work that way in the rear. I will add valves there if I have to for that purpose. That way I'll be able to drop it onto the bump stops before leveling which has two benefits. First it makes that first step into the RV much more manageable, and second and every bit as important, because the ride system will air up before rolling out it will lift the leveling jacks off the ground.

I'm not saying it's acceptable practice to drive it that way, just that it makes a good safety measure to be sure the jacks don't get damaged in a drive away, which we've all seen. A walkaround should be part of every departure but anyone can make a mistake.

So does anyone know offhand if the valve(s) that return the rear-lift to standard ride height can be used as dump valves? (or did they just use the standard leveling valves to do it? ...probably)

Finally, because the door is air operated I should have air and power available to operate that whenever possible but I do not need air to anything besides the door that I know of. So which tank provides air to the door? What else does that tank supply, and is it isolated by a check valve? In other words can I relocate my compressor to the front and just air up that tank, or will I have to re-plumb the door supply?

Unfortunately the online manual is incomplete and the air and wiring diagrams have been cut short making them near useless.

Jim

thomasinnv · September 20, 2020, 11:28:00 AM

Jim, on the D series the tag axle air bags are tied in with the drive axle. 2 bags on the tag axle, 4 bags on the drive axle...the drive to tag axle weight distribution is 2:1. The tag axle is not "directly" connected in the sense that it has a series of control valves for tag axle unloading, but under normal driving conditions it is essentially one single air system for each side, right and left rear.