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MCI 102-C3 coach to RV - Chassis/Suspension

JNHEscher

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This thread is the chassis and suspension offshoot of the original thread that migrated from Pirate4x4. As the subtitle implies, this will detail the heavier chunks of metals that dangle from the underbelly of the bus. The mother thread, which begins as the bus purchase and teardown, lies here - https://irate4x4.com/tow-rigs-and-tr...eral-floorplan

The second post of this thread is where I began gawking at the subframes and pondering the leveling system and axle swap.
 
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JNHEscher

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On the leveling jack idea, I've been piecing a few things together in my head. The 20-ton bottle jacks do well to lift one end of the bus. I don't think I would want to use any lesser capacity, so to find some 20-ton cylinders with a reasonable stroke would work. Specifically those with cup seals. I need a foot pivot. A 2-5/16" gooseneck ball with a 20-25k pound capacity sounds good. I just need to come up with a receiver of sorts to retain it. And lastly, a telescoping tube assembly that can latch with a ratchet or something.

RV leveling jack systems seem to be out of the question. Since a coach bus is considerably heavier than your typical RV, the available systems look be too wienie to be comfortably stable. I'd like to mount the jack on the axles so that they could double as maintenance jacks for pulling tires off and such. On-board tooling comes in handy all the time.

Not that I'm trying to outdo a system like the Big Foot Class A setup. It's just a great feeling to save a few grand and make something yourself that can be overkill and kill two or more birds with one stone. That and I haven't found anything showing that the leveling systems are capable of lifting the vehicle high enough to get the tires off the ground.

Since the MCI buses are of unibody construction, running the cylinders in unison to lift it is kind of a necessity. I think there's enough auto leveling controllers out there now to make all this work seamlessly. One way or another, building some serious jacks sounds the most enticing at the moment. Throw me your $0.02 if ya like.

Edit: Forgot to add that I want a pair of jacks on each of the three axles.
 

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Java said,

Can you dump the air enough that jacks in the axles will be able to level? Seems like frame/body mounted would be better.

Are you OK with cutting up the storage bays? There had to be room for a 20" cylinder mounted in there aiming down somewhere.

Out old rig had flip down hydro ones. They were so nice for tire changes! Ours were single acting with a spring for return and flip up.

I would not use a controller personally.... Out never worked with a crap, but it was mid 90's engineering. I just manually did it by feel.
 

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Java said:
Can you dump the air enough that jacks in the axles will be able to level? Seems like frame/body mounted would be better.

Are you OK with cutting up the storage bays? There had to be room for a 20" cylinder mounted in there aiming down somewhere.

Out old rig had flip down hydro ones. They were so nice for tire changes! Ours were single acting with a spring for return and flip up.

I would not use a controller personally.... Out never worked with a crap, but it was mid 90's engineering. I just manually did it by feel.

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Click to expand...​
Dumping the air sets it on the bump stops. There's some steel subframe tube work over each axle for the suspension. All the bays are aluminum that won't handle the weight. Not much to mount to within the bays, either. I'd be pretty happy with manually operating the jacks. Just have to be sure not to tweak the body too far. A controller would be more than half the cost of the whole system anyway. So far, I would still rather build the jacks. Can't find much in the way of grader balls for foot pivots. Gooseneck balls are $20 each, but need a socket of some kind.
 

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Java said,

Cool, If its on bump stops that should work well, if there is room on the axle for rams.

Why do you need the ball? I see most RV's with a round plat/foot with a little dish to it. Mine were ~3" square flat plate, I threw a chunk of 2x6 under them in soft/snow. Which reminds me, if you use them in snow/ice and have single acting rams, they will freeze to the ground and not retract. Mine being flip up it was not the end of the world, just pull forward a couple feet and they broke free.
 

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All kinds of room for stout mounting on the axles. I'd be hard mounting them since they're damn near inaccessible under the bus. I have to turn the wheels full lock just be able to squeeze between the tire and fender in order to get a bottle jack under the axle when the bus is aired down. I'm working to set it up so it's a piece of cake to lift.

Shooting for the heavier duty ball pivot because of the amount of weight that'll be placed on them. I've seen that the RV feet are just a small ball in a plate held with springs or double-shear bolt mount. Neither look like they'd withstand the force of being ripped out of frozen ground. The gooseneck ball is cheap a super beefy. I'm looking up tongue sockets that I could cut and weld into some vertical tubing. Have to create a ball socket shell somehow without running the bill up too high. Also considered 1480 u-joint and two flange yokes. That's fancier than I need, but if the price is right and the needle bearings could take the force, it works.

Figured that I really don't need the telescoping tubes to ratchet since it doesn't need to lock when we're just using the jacks for leveling. I just need some pin slots or something like a sleeve block to lock it when I'm getting underneath the work on the bus. For that matter, there doesn't need to be tubes. I can mount a foot pivot the cylinder shaft and add on a block like what's used on front loader bucket cylinders to block it up for working underneath the bucket. I was planning to mount the cylinders inside some tubing to keep the crud off, but they'll be retracted most of the time anyway.
 

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Just noticed your build thread too, Java. I came across that site before we even purchased our bus. Sweet build, man. I was ecstatic to see that I wasn't the only one framing with steel instead of 2x4's.
 

JNHEscher

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Java said,

Thanks! Yes steel makes a lot of sense, in places!

Why the ball/pivot at all? Why not just a ~6" round disk on the end of the ram?
 

JNHEscher

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To compensate for uneven ground, mostly. I'm planning for us to be parking in the middle of nowhere on many occasions and I'd like to not have to find a flat enough area for a 40 foot bus. Seems like a wise idea to provide a pivot so as not to bend anything critical. Thought a hefty ram probably wouldn't care lol. I'll be putting plates at least 10" in diameter on it which should help in the event that we park in really soft ground. Been there numerous times during the rainy summers in central Missouri.
 

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Java said,
JNHEscher said:
To compensate for uneven ground, mostly. I'm planning for us to be parking in the middle of nowhere on many occasions and I'd like to not have to find a flat enough area for a 40 foot bus. Seems like a wise idea to provide a pivot so as not to bend anything critical. Thought a hefty ram probably would care lol. I'll be putting plates at least 10" in diameter on it which should help in the event that we park in really soft ground. Been there numerous times during the rainy summers in central Missouri.​
Coot, I see why, just seem over complicated. make that 10" plate have a bit of lateral grip and call it good.
 

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Maybe some expanded steel welded to the bottom of the plates. I could get away without having pivots for most uses. If I do want to lift one end of one axle to change a tire, that will probably put enough angle on the cylinder to bend a plate that's simply welded to the shaft. Just my take on it by eyeballing how much the axles articulate when one end is lifted.
 

JNHEscher

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I'll be using a switch or gauge on the lines to tell when the feet are in contact. Much easier that way to tell rather than watching for movement.

I saw that coupler on etrailer but wasn't entirely sure what the connection was like because they don't show the underside. I'm thinking a coupler like that if it isn't too loose, or some DOM tubing that slips over the ball that I can cap off on top and weld a retainer ring to on the bottom that slips over the ball flat before I weld the ball to a plate. - threw together a quick cad version.

236.jpg
 

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Kids woke up so I husteld them into the bike cart and rode to Tractor Supply a few blocks away. Grabbed a 2" and 2-5/16" to take to Ecodynamics and fit in some DOM. The 2-5/16" measures 0.0075" under and the 2" measures 0.002" under. Eco has DOM with a 2" ID but no 2.3125" ID on hand. Ball load ratings are 5k and 25k. Quite the difference, but I'm pretty sure that's shear stress and not compression which is all they'll really see on a leveling jack setup.

237.jpg
 

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Elwenil said,

Yup. They can handle a pretty decent amount of weight, can be had off of trucks like an F550 and won't need to support the entire weight of the vehicle as you are just shifting it around a bit.
 

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That crossed my mind, but I didn't give it much consideration because most seem like they'd be a bit small for this. I haven't had the opportunity to eye an F550 ball joint, though. Depending on the brand, they run about the same price as using the hitch ball and building DOM cups, give or take a few bucks. Mounting a ball joint between a cylinder and foot plate might be interesting.

I'm still in talks with owners of the Quadra Bigfoot Class-A system. Seems to be a worthy setup. I still have to pick out the right cylinders, pump(s), lines, etc. to build a system so I can weight the pro's and con's between building and buying. $4,200ish is the best price on the Bigfoot that I've found.
 

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MarkObtinaro said,

MCI built in some lifting points which would be a better place to try and lift the coach. By lifting at the lifting points you would be getting the weight off of the suspension and the tires.

Trying to use jack stands under the axles to level your bus up would mean your bus would still be riding on the suspension. Whether the system was air'ed up or not it most probably would not sit level on the axles on level ground. You can't get all of the air out of an air suspension and some of the bags might still retain some pressure.

You would also have an issue of ground clearance. There isn't much space under an MCI axle when the tires are full of air. If you were to blow a tire your leveling jacks would start dragging on the ground.
 

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MarkObtinaro said:
MCI built in some lifting points which would be a better place to try and lift the coach. By lifting at the lifting points you would be getting the weight off of the suspension and the tires.

Trying to use jack stands under the axles to level your bus up would mean your bus would still be riding on the suspension. Whether the system was air'ed up or not it most probably would not sit level on the axles on level ground. You can't get all of the air out of an air suspension and some of the bags might still retain some pressure.

You would also have an issue of ground clearance. There isn't much space under an MCI axle when the tires are full of air. If you were to blow a tire your leveling jacks would start dragging on the ground.
Click to expand...​
If I can get some cylinders mounted to the lift points, that'd be the route to go since it would also allow me to replace bellows and shock and possibly service the air brake chambers much easier. At the moment, it's a matter of wedging myself in there to measure. That and battling the fire ants that are busy on the surface now. The few people I've heard from with the Bigfoot system that has 18" stroke cylinders confirmed for me that it will lift the tires off the ground. And Quadra mounted their cylinders to brackets that they fabbed up to mount to the lift points.

I'm not working to dispute anyone's knowledge of MCI's, especially since I'm still learning these. When our bus is aired down, it really is on the bump stops and it is very steady. The remaining bit of bounce comes from the tires. No air left in the bags and I'd certainly empty the system when parking.

My intent for mounting cylinders to the axles is to set them offset from the beams and place the retracted cylinder feet near flush with the bottoms of the axles. That wouldn't drag the ground if the a tire blew out or wheel fell off. Biggest downside to mounting cylinders on the axles is that the cylinders add unsprung weight and will receive all the shock that the axle sees.

If they'll fit, I'll go for lift point mounting. I'll be at the bus tomorrow and might be able to skinny underneath to see what I can make happen. Riding to Napa in a bit so I can measure some F550 ball joints. Using those for pivots would simplify the assembly a lot, as long as they're beef enough.
 

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ennored said,

Did you research air leveling? HWH has a system. Lots of info on it out there. Their brochure. Very pricey. But, to me, you already have airbags, it's just a matter of creating a control system.
 

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ennored said:
Did you research air leveling? HWH has a system. Lots of info on it out there. Their brochure. Very pricey. But, to me, you already have airbags, it's just a matter of creating a control system.​
I've seen a lot of sweet air leveling systems. Disregarded going that route since the air bags are huge and the bus can sway a fair amount while being supported by air. A hydraulic, standalone system will give it really solid support. The added ability of the hydraulics is being able to lift the tires off so that I can do roadside work without having to drag out a floor jack or call for a wrecker. The more on-board tooling I have for maintenance, the better. Much like keeping tools handy on the trails.
 

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Now that's a ball joint. Took Elwenil's suggestion and pulled up a 2014 Ford F550 4x4 pair of steer ball joints. This is the lower joint. It's about as big as the 2-5/16" trailer ball. For $33.xx at Napa, this is the best option. Only problem to overcome is the cup measuring 2.434" in diameter. I'm avoiding the need for any machine work to be done to make the cylinder feet, but for as cheap as these are, I think I can have Eco open up the ID of whatever DOM tubing I find to press these into.

I can't easily check the articulation angle of this. From the looks of it, it'll tilt as much as any other ball joint which is plenty for a jack foot. It's sealed very well, too. Sealing and lubrication wasn't much of a concern, but a huge plus.

238.jpg
 

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GLTHFJ60 said,

Looks like that will fit the bill quite well!! How much load will be put on each ball joint? Thinking that the load will be carried by just the lip on the ball joint, and maybe a small internal shoulder, I'm curious how much weight will be applied compared to the original application.
 

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GLTHFJ60 said:
Looks like that will fit the bill quite well!! How much load will be put on each ball joint? Thinking that the load will be carried by just the lip on the ball joint, and maybe a small internal shoulder, I'm curious how much weight will be applied compared to the original application.​
I don't have a certain weight figure to go by, but from what I've read, many of these MCI conversions are weighing in the high 20K's. I'm overestimating at 30k pounds to be safe. Thinking somewhere around a 40/60 weight split front to rear. The ball joints will be under compression which should handle quite a bit of weight. If I'm right at all, there will be 9,000 pounds or less on each rear ball joint at a gvwr of 30k. Somebody will know more than I.

These won't see anywhere near the kind of use they're designed for. They will, however, be splitting the weight of the bus for as long as three months at a time. Just parked, though. So they'll typically only see the weight of the bus body. I do need them to hold the weight of the entire bus for the maintenance reasons stated earlier. I'm all for making this a 6-post lift if need be. Only need 4 posts if I mount the cylinders to the lift points, but the rear of the bus has the drive axle (heaviest of the three), tag axle, engine and trans, and all batteries will be over top of or behind the rear axles. The front will have plenty of weight for balance, though not as much as the rear.
 

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aczlan said,
GLTHFJ60 said:
Looks like that will fit the bill quite well!! How much load will be put on each ball joint? Thinking that the load will be carried by just the lip on the ball joint, and maybe a small internal shoulder, I'm curious how much weight will be applied compared to the original application.​
Per: https://www.fleet.ford.com/truckbbas...s_SB_specs.pdf the F550 was available with up to a 7,000# front axle weight rating. That would be 3500# static load on each side, if its designed to handle a dynamic load of 4x the static load, it should be good for 14,000#/balljoint in a static application such as this one.

Aaron Z
 

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aczlan said:
Per: https://www.fleet.ford.com/truckbbas...s_SB_specs.pdf the F550 was available with up to a 7,000# front axle weight rating. That would be 3500# static load on each side, if its designed to handle a dynamic load of 4x the static load, it should be good for 14,000#/balljoint in a static application such as this one.

Aaron Z​
Hell yes. Thank you, man. I think I'll be quite happy with these. The upper (smaller) ball joint would be a little easier to couple to the cylinder shaft, needing only one length of 2"-0.500" wall DOM. Think I'll stick with the lower joint, assuming it has more capacity. Place any of these beside the bus and they'll look small. I'll like to build my projects with the least probability of failing. This should do it.
 

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aczlan said,
JNHEscher said:
Hell yes. Thank you, man. I think I'll be quite happy with these. The upper (smaller) ball joint would be a little easier to couple to the cylinder shaft, needing only one length of 2"-0.500" wall DOM. Think I'll stick with the lower joint, assuming it has more capacity. Place any of these beside the bus and they'll look small. I'll like to build my projects with the least probability of failing. This should do it.​
Glad to be able to help. I would strongly suggest that you install a check valve (such as: https://www.surpluscenter.com/Brands...-7933-8-65.axd ) on at least the extend side of the cylinder (come right off of the cylinder with an elbow and install a check valve). That one requires 65 PSI more pressure from the valve than is on the other side before it will open up and let the cylinder retract, they have others that are setup for a 5 PSI pressure differential from the valve.
If you do that, you won't have pressurized hydraulic lines from the cylinder to the valve when the bus is on the cylinders.
If you have a 2" bore cylinder, it looks like 2500PSI of hydraulic pressure would let each cylinder lift about 12,000# (per the calculator at: https://www.surpluscenter.com/Tech-H...r-Force-Speed/ ).
They also have a hydraulic motor calculator ( https://www.surpluscenter.com/Tech-H...eed-Torque-HP/ ) which you could use if you wanted to setup the hydraulic system to run a hydraulic fan as well as powering the hydraulic cylinders.
 

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x2 on the check valve. Just have to be able to relieve the pressure from all cylinders. I'm thinking the shaft side of the cylinder on a dual-acting might make a good return spring if I plug it. I've been mulling over the best valve setup to use on this. Something simple that offers 4-way control. Swaying towards using the power steering pump to operate the system if I can make that work. It's gear-driven and uses straight 10 weight oil. Not entirely sure what the output pressure is yet.

Gotta brush up on my hydro valving. What would be ideal in my eyes is a control that can operate the cylinders individually and in pairs. Say, the ability to bump one corner when needed, but also lift both fronts, both rights, both rears, or both lefts in unison. Joystick control came to mind, but those require extra spools and I'm not sure one valve block would control all four cylinders. Kinda staying away from electric valves because of the jerky motion, but that may be just fine on a system of this size. Electric solenoid valving would eliminate a lot of hydraulic line length.
 

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aczlan said,
JNHEscher said:
x2 on the check valve. Just have to be able to relieve the pressure from all cylinders. I'm thinking the shaft side of the cylinder on a dual-acting might make a good return spring if I plug it.​
I would suggest using a up and down hose on the cylinder, that way if you park somewhere and the feet freeze to the ground, you can pull them up.
JNHEscher said:
I've been mulling over the best valve setup to use on this. Something simple that offers 4-way control. Swaying towards using the power steering pump to operate the system if I can make that work. It's gear-driven and uses straight 10 weight oil. Not entirely sure what the output pressure is yet.​
Pressure is easy to measure, put a tee and a $15 gauge in the system between the pump and the valve, crank the wheel over to the stop and hold it there. Its probably under 3000PSI.
The bigger issue for valve sizing would be flowrate. What size are the hoses? If you know the hose size, you can use a chart like the one below to find the correct size:
Nomograph1.jpg

Source: https://www.ryco.com.au/technical/ge...ion-nomograph/
JNHEscher said:
Gotta brush up on my hydro valving. What would be ideal in my eyes is a control that can operate the cylinders individually and in pairs. Say, the ability to bump one corner when needed, but also lift both fronts, both rights, both rears, or both lefts in unison. Joystick control came to mind, but those require extra spools and I'm not sure one valve block would control all four cylinders. Kinda staying away from electric valves because of the jerky motion, but that may be just fine on a system of this size. Electric solenoid valving would eliminate a lot of hydraulic line length.​
I would use electric valves (perhaps something like: https://www.surpluscenter.com/Brands...lve-9-7987.axd ) and a restrictor orifice to control flow.
Then 4 SPDT momentary on switches at your "control panel" and a 8 channel wireless remote (such as: https://www.amazon.com/Channel-Wirel...dp/B01GH7IK2E/ ) and you are good to go.
41Qr3wu4-xL.jpg

If you wanted to run front/back up/down together you could add a momentary on, DPDT switch switch and wire both solenoids at one end through it, for all down you would use a 4PDT switch or a SPDT switch with diodes to each corner (so that they cant backfeed when you just want to run one corner up/down).
If you ran solenoid valves off of your power steering system, you could run one bank up front and one bank in the rear (both before the power steering controls as there is no easy way to know if it can handle back pressure on the tank port of the power steering valve) which would greatly reduce your hose needs.
On the idea of a hydraulically powered fan, this looks like it would be a simple way to control hydraulic fan speed if you wanted to go that route: https://www.surpluscenter.com/Brands...-9-5178-30.axd

Aaron Z
 
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