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MCI 102-C3 coach to RV - Chassis/Suspension

Same valve I had pulled up last night. I'm curious if it would hold the pressure or if I'd still need to plumb in check valves. All I know about the system pressure at the moment is that the pump is either 1,000 or 2,000 psi. Have to see if I can find a part number on it tomorrow.
 
aczlan said,
JNHEscher said:
Same valve I had pulled up last night. I'm curious if it would hold the pressure or if I'd still need to plumb in check valves.​
They SHOULD hold, but I would probbaly still plumb in check valves as insurance against a line blowing, or the valve leaking (given that you want to leave it sitting on this for months on end). All hydraulic valves leak a little, the only question is how much.
That valve is only good for 5GPM of flow by the way, if your pump flows more than that, you will need something like: https://www.surpluscenter.com/Hydrau...lve-9-6136.axd with a subplate such as https://www.surpluscenter.com/Hydrau...r-9-5883-1.axd which are good for 10GPM.
Any more than that and your cheapest options would be a random valve on eBay, or recycle some of your air actuator cylinders to operate the hydraulic valves.
JNHEscher said:
All I know about the system pressure at the moment is that the pump is either 1,000 or 2,000 psi.​
If you want each corner to be able to lift 10,000# (worst case, what the low corner would see when sitting nose up at an angle on a slope), with 1000PSI you will need almost a 4" bore cylinder (a 3.5" bore cylinder would give you ~9600# of lift). If its a 2000PSI system a 2.5" bore cylinder will lift ~9800# and a 3" bore cylinder will lift over 14,000#
JNHEscher said:
Have to see if I can find a part number on it tomorrow.​
I would bet that the steering box is either 11G-1-1 or 11J-1-1 (per: COACH GUARD POWER STEERING COMPONENTS | Motor Coach Industries ). Good luck getting more info on the pump, I was digging a little last night to find pressure or flow ratings (just based on the bus model number), but couldn't find much of anything.

Aaron Z
 
I was looking to go with a 3.5" bore. The pump should be an OE Vickers. Generally 1,000 psi, but upped to 2,000 at some point for easier steering. There should be a part number cast on it under the ten pounds of oily gunk caked on. MCI ought to have an answer for me if I call them up with the part number. It may very well be 2k. I can turn the wheel with one finger while parked.

Depending on what bore and stroke I decide on, the upper chamber should be around half a gallon per cylinder. I stuck my head in the wheel wells today to get a feel for how easily I could take some measurements. Tight space for a body.

Perhaps a ball valve at each cylinder would be the simplest. Set the level and lock it. I'm hoping to mount the cylinders as far outboard as I can. Reaching a ball valve handle wouldn't be all that difficult, in that case.
 
aczlan said,
JNHEscher said:
I was looking to go with a 3.5" bore. The pump should be an OE Vickers. Generally 1,000 psi, but upped to 2,000 at some point for easier steering. There should be a part number cast on it under the ten pounds of oily gunk caked on. MCI ought to have an answer for me if I call them up with the part number. It may very well be 2k. I can turn the wheel with one finger while parked.​
Good to know that they will do that for mere mortals
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JNHEscher said:
Depending on what bore and stroke I decide on, the upper chamber should be around half a gallon per cylinder. I stuck my head in the wheel wells today to get a feel for how easily I could take some measurements. Tight space for a body.​
If you use both sides of a couple acting cylinder, that will help reduce how much extra fluid capacity you need to add.
JNHEscher said:
Perhaps a ball valve at each cylinder would be the simplest. Set the level and lock it. I'm hoping to mount the cylinders as far outboard as I can. Reaching a ball valve handle wouldn't be all that difficult, in that case.​
IMO, a check valve would be simpler, cheaper and safer as you just have to "lift" the bus a little before you lower it with a check valve vs reaching in all 4 corners to release the ball valve and hope that you haven't lost pressure in the lines or gotten an air pocket (causing the bus to drop unexpectedly when you open the valve), but either should work.

Aaron Z
 
Yes, a check valve would be easier. I've been a bit strung out on lack of sleep lately. Couldn't get my brain the think of how on earth I would release a check valve once pressure were set on it. Duhhhh. Check valves, solenoid valves, a few feet in hoses, and some switches should cover most of it. Wireless? Maybe.

Car Quest may have the four-way fittings I need to tie into each end of the steering system. The cylinders will only be a few feet from either end of the hoses I had made. Can't really choose a bore until I know for sure what pressure I'm working with. Power steering, wiring, and fuel lines are currently disconnected so I can't quite throw a gauge on just yet. Getting these conduits set up so I can feed all my lines through them and hook all systems back up.
 
aczlan said,
JNHEscher said:
Car Quest may have the four-way fittings I need to tie into each end of the steering system.​
4 way fittings? If its like most such systems, its an open center hydraulic system, so the pump is always pumping fluid through it in a loop from the pump to the tank. On the one of our tractors the fluid is at ~250PSI and ~8GPM until you use a valve, then the pressure climbs enough to do the work that you are asking of it (or you get enough pressure to trip the relief valve).
Any new valves need to be in series, if you put them in parallel the fluid will take the path of least resistance and just go back to the tank.
Here is a diagram of an open center system running to one valve (source: Hydraulic Open-Center System | Hydraulic Valve ):
open-centre-system.jpg

This is how your current system is plumbed (other than it has a steering valve and a hydraulic steering box rather than a standard valve and a ram).

Here is how your system will need to be after you add more valves (source: Hydraulic Open-Center System | Hydraulic Valve ):
open-centre-system-series-connection.jpg

I would strongly suggest that you put the new valves in line between the pump and the steering valve so that the steering valve remains the last valve in line.
The reason being that if they didn't design the steering valve to handle back pressure on the outlet (return to tank) port, it may only be setup for "low pressure return" (ie: 200-300PSI) and if you added a new valve after the steering valve, the backpressure on the outlet port of the steering valve could cause a catastrophic failure.

Aaron Z
 
Spaced out on this last night, apparently. I already knew it was open center. Why four-ways popped in my head, I do not know. So anyway, I need to come up with pump specs. I'll pick at it today.

Edit: I need to add that the PS hoses are 1/2" ID and the fitting end sizes are -10 JIC. The 65 feet of copper line that the PS fed through originally was 1/2" ID. The OE hoses connecting each end of the copper pipes to their respective components were much larger and supposedly rated at 2,500psi. The hoses I had made are rated at 3,250 working pressure and right around 12,000 burst pressure per Gates' specs. And they're 50 feet each. Might produce a little more heat, but that's alright.
 
Found it. PDF on Vickers pumps shows this one to be the VTM42 with 5.5gpm and 1,500psi relief setting. All pumps are capable of 2,000 and it appears that I can easily change the setting.

Detroit Diesel built their engines with mirror mounting for many accessories. Technically, I could mount a second pump on the other side without disturbing the power steering, but I don't really have a need to.

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Ample space for cylinders up front. This location off the lift point is as far outboard as I can go on the body. Haven't much of an idea of what stroke I would need until I get some more jacks to lift this enough and let the axle droop.

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aczlan said,
JNHEscher said:
Ample space for cylinders up front. This location off the lift point is as far outboard as I can go on the body. Haven't much of an idea of what stroke I would need until I get some more jacks to lift this enough and let the axle droop.​
How far is it to the ground there? Something like: https://www.surpluscenter.com/Brands...-8263-16-S.axd might work, 26.25" retracted length, 16" stroke. If you remove the rod end clevis, you should be able to put your adapter to the tie rod on the end in place of the clevis.
If you have enough room to clear when retracted, they also have a 18" stroke version: https://www.surpluscenter.com/Brands...-9-8263-18.axd
It could mount with the clevis at the top and you could make a plate to bolt under the ends of the tierod bolts at the rod end which then ties back to the frame to stabilize it.
3.5x16x1.5+DA+Hydraulic+Cylinder+Lion+35LH16-150+3000+PSI_R.jpg


On getting the wheels off of the ground to change a tire, what if you added a couple of anchor points above each axle so that you can dump the bags, loop the chain under the axle, then raise the bus with the feet?
That way you dont have to have enough stroke length in the feet to get the tires off of the ground at full droop.

Aaron Z
 
Not sure yet on distance to ground or between a body point and axle beam. The ground is very loose and lumpy sand.

Figured I'd go for welded cylinders for the strength. I had the same mounting idea for tie rod cylinders. Tie rod ought to hold and save a few bucks.

On the rear, there's a hook welded to the frame above each side of the tag axle. I was wondering if they're there for that reason (to hold the axle up while lifting). If I'm mounting to the body lifts, I'll probably stick with enough stroke to lift the tires with the suspension at full droop. There's not much room at all to reach in far enough to chain the axles. Particularly the rear. Air bag inspection is far easier with the tires dropped down.
 
ennored said,

The jacks on my motorhome won't lift the tires cleanly off the ground at both ends. But they are like 8" off the road surface all the way up. Real easy to stick a block of wood under them for extra lift when needed.
 
Think I'm gonna avoid the wood blocks as much as I can on this for safety's sake. It's enough weight to make me leery of the odds that wood might split and drop a corner. So long as I have the room for the stroke required, it's full hydro.
 
Elwenil said,

Unless you are buying the worst quality wood available wood is more than up to the task of holding up the little bit of weight that bus weighs. Wood cribbing is used extensively in lifting operations all over the place lifting some real weight.
 
In our current location, it is the worst quality available. Sucks, but true. If I don't have to carry blocks around, I'm all for using cylinders that extend as far as needed to lift the whole bus. Looks like I have the room for such. Don't mind block cribbing. It's mostly the space it occupies when not in use.
 
MarkObtinaro said,
JNHEscher said:
On the rear, there's a hook welded to the frame above each side of the tag axle. I was wondering if they're there for that reason (to hold the axle up while lifting). .​
The hooks are there to hold the axle up while lifting.

They are also handy for when you get a flat and use a tag axle wheel and tire as a spare. Chaining the tag up keeps it from touching the ground until you can get another wheel and tire mounted on the tag axle.
 
Jrod-13 said,
JNHEscher said:
Yes, a check valve would be easier. I've been a bit strung out on lack of sleep lately. Couldn't get my brain the think of how on earth I would release a check valve once pressure were set on it. Duhhhh. Check valves, solenoid valves, a few feet in hoses, and some switches should cover most of it. Wireless? Maybe.​

What you want is cylinders with counterbalance valves(or add external ones),
something similar to this
 
mjlogan88 said,

Wood can take quite a bit in compression as long as you support it. Each one of these slabs weighs 30,000 lb and has 2 regular old 4x4's under it. Thats 120k lb on the bottom 2 4x4's.
 
I was able to get one jack under a lift point to start lifting the body then sneak the other jack in. 15ish inches from the lift point to the ground gets just enough space under the tires to spin them. There's more than enough room for a 18" stroke cylinder with the cylinder foot at the same height as the lift point when retracted.

249.jpg
 
aczlan said,
JNHEscher said:
I was able to get one jack under a lift point to start lifting the body then sneak the other jack in. 15ish inches from the lift point to the ground gets just enough space under the tires to spin them. There's more than enough room for a 18" stroke cylinder with the cylinder foot at the same height as the lift point when retracted.​
That should fit nicely then.
Did you see this one? https://www.surpluscenter.com/Hydrau...06-9-10147.axd

Aaron Z
 
aczlan said,
JNHEscher said:
I hadn't. Not sure I'm keen on using that one. Now that I have some close measurements, I think I can pick out a tie rod cylinder for the fronts. Still have to get to the rear.​
I thought the mounting base was interesting, it would be a long lever to have unsupported...

Aaron Z
 
Sure took a while, but I managed to get jacks lined under the rear. About the same as the front. Around 15" between the lift point and ground to get the drive tires just off the ground. The tag axle doesn't droop nearly as far, so no real need for chains to hold it up.

Mounting cylinders on the rear is a little more troublesome. The only decent place to set them is betwixt the drive and tag tires. There's not a whole lot of room, though 4" cylinders would fit fine. If a tire blowout we're to occur, the cylinder would get slapped pretty hard. Probably nothing to worry about.

There is some room for cylinders inboard of the axle links, but this would place them too closely together and loose some stability. Either way, I have room for a cylinder with a 25" collapsed length. I don't really want to go crazy with cylinder stroke. Although it seems worth getting the longest I can fit so I can level up on some sleep stuff. Just have to make feet with good traction.

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Somehow, I come out as the cleanest of the crew at the end of the day. The boys sure dig in.

We tried out the $40 Chinese torque multiplier. I cannot complain. With a 12" crank handle, it breaks and tightens lug nuts without dislocating your shoulders. Swapped the spare in place of the flat steer and pulled the drive wheels off one side so I could get a better look at everything. Four of the nuts on the outer drive wheel weren't torqued. Found that the intermediate nuts were loose.

I've been planning to replace the air bags after a while. The drive axle bags will be first. Dunno what happened here, but the top plates on all four bags are all but gone. They oxidized with severity and it didn't affect the mounts. I am quite surprised that neither of them have separated yet.

Shocks are another one. The right side drive shocks are roughly 1" smaller in diameter than the left side drive and tag axle shocks. The left side ride leveler valve bracket has been scraping against the fowars left drive shock. It seems to me that the person that performed the repairs in this bus's previous service was throwing on it whatever they could acquire.

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87manche said,
JNHEscher said:
It seems to me that the person that performed the repairs in this bus's previous service was throwing on it whatever they could acquire.​
sounds about right for fleet service.

uptime is everything. Slap whatever's laying around in the shop on it that fits and send it back out.
 
Got a little time to yank out the rear air tank today. Sounded like a swell idea to relocate it to the engine bay where part replacement accessibility would be worlds easier. Having to remove the wheels to get to all those air lines and valves is a bit much.

I have another order of DOT air lines on the way to reach the new location. Where exactly I'll mount the tank, I don't know yet. At least somewhere easy on air line routing. There's a nice opening for axle work now, as long as I don't mount are larger tank in the hole.

Compressed air is pretty handy, so I've had the idea of a supplementary air tank on the bus for tools and being able to quickly jump start the air ride and brakes at times. If the solar setup grows enough to supply and decent dump load, I'd like to use it to power a small compressor rather than the usual water heater element or fan suggestion. The compressor could keep the tank topped off and a governor would blow off excess through a muffler/diffuser.

Had a local shop pull my flat off the rusty wheel so I could get a width measurement. The dude that did the work was busting his ass so hard that I let him keep the change off my $20. Hopefully all our wheels aren't this bad, but this one somehowade it from Dallas without letting the tire loose.

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Made an inquiry about releasing the park brakes last night. One guy knew exactly what I was after and steered me in the right direction. All I had to do what unbolt each chamber from the bracket. Thought I would post this as reference to anyone else needing to release their DD3 brakes without air assistance.

Got a friend helping source a tow rig to pull our bus to our current residence. It’s only a 23 mile trek up a dirt road. I need it here so I can work on it any time. Since the snow started flying at higher elevations next to us, we figured we had better get on it before snow hits the valley and we lose all traction.

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aczlan said,
JNHEscher said:
Made an inquiry about releasing the park brakes last night. One guy knew exactly what I was after and steered me in the right direction. All I had to do what unbolt each chamber from the bracket. Thought I would post this as reference to anyone else needing to release their DD3 brakes without air assistance.​
There weren't bolt holes in the other side of the chamber to put a bolt into and "cage" the brakes? That is how they normally do that.

Aaron Z
 
Not that I’m aware of. A couple people told me that the DD3 style I have isn’t the one you can cage. These have the sprag type clutch that holds them. I could have put air pressure to the lock ports to release them, but the two nuts on each chamber only took a couple minutes.
 
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