MCI 102-C3 coach to RV - Chassis/Suspension

[JNHEscher]

Grendel said,

02rexwi said:
You'd be good with the 4000 series.
Brakes may not be ideal though. I believe you'll have hydraulic brakes on the 4000 series, but they could be converted to air fairly easily.​

No, they're air.

I found hydro calipers if need be, but the ones I get are air.

 

[JNHEscher]

Every 4000 I pulled up was air brakes with Haldex calipers. A few switched over to hydraulic. I haven't sized our stock chambers yet and I'm sure I wouldn't come up with a proper brake force calculation for either system. The 5000 ISAS has inboard brakes which would have no trouble at all.

 

[JNHEscher]

02rexwi said,

Grendel said:
No, they're air.

I found hydro calipers if need be, but the ones I get are air.​

I was referring to the 4000 ISAS

 

[JNHEscher]

02rexwi said,

JNHEscher said:
The 5000 ISAS has inboard brakes which would have no trouble at all.​

I got to experience some dyno testing of those brakes in person. They're pretty insane.

 

[JNHEscher]

02rexwi said:
I got to experience some dyno testing of those brakes in person. They're pretty insane.​

Apparently. JD8420 sent me the youtube video of them being tested. Second run of locking them up at 60mph ripped the subframe out lol. I can't imagine the 4000 outboards would fall short of stopping our bus. I could possibly bump the service chambers up to the next size if needed, but I think I remember the 24 being the largest available for the given bolt pattern.

The OE drum chamber rods push on a lever that turns a shaft with an S cam that then places force on some crazy wide shoes. Multiple points of mechanical advantage there.

 

[JNHEscher]

bdkw1 said,

JNHEscher said:
Apparently. JD8420 sent me the youtube video of them being tested. Second run of locking them up at 60mph ripped the subframe out lol.​

Link? I likes some good carnage.

 

[JNHEscher]

bdkw1 said:
Link? I likes some good carnage.​

https://youtu.be/9-44vU0lrAg

Bear in mind that I would have two of these under the rear of our bus. Outboard brakes may be just fine lol.

 

[JNHEscher]

bdkw1 said,

LOL, the driveshaft bouncing around in there.

Yeah, those might have enough brake on them.

 

[JNHEscher]

Grendel said,

JNHEscher said:
Every 4000 I pulled up was air brakes with Haldex calipers. A few switched over to hydraulic. I haven't sized our stock chambers yet and I'm sure I wouldn't come up with a proper brake force calculation for either system. The 5000 ISAS has inboard brakes which would have no trouble at all.​

I'd be interested in hydro calipers.

 

[JNHEscher]

Grendel said:
I'd be interested in hydro calipers.​

There's a few threads around detailing the custom setups. Don't think anyone has considered a production run.

 

[JNHEscher]

02rexwi said,

Grendel said:
I'd be interested in hydro calipers.​

I can hook you up with the Axletech fixed 4 piston hydraulic caliper setup, but cost is going to be a lot higher than people using dodge ram calipers.

 

[JNHEscher]

Looking around, I spotted a cracked compression nut. And them a much larger crack in an L fitting that the 1/4" reference line runs through for the compressor governor. These cracks were plenty dirty, suggesting that they were present before we purchased the bus. I also found why our steering gets stuck when you turn it full lock to the right. Toe adjustment clamp catches on the airbag bracket.

 

[JNHEscher]

FirstRam said,

How much did this bus weigh in stock form? I was handed a project at work yesterday which will involve using airbags to simulate a bus accident. We have to violently rock the bus side to side, spilling the contents of the overhead storage compartments.

The bus is a 50 seat 1988 MCI. I plan to remove the tag axle, shocks and sway bars and leave the bus sitting on its tires. We just don't have time to build to build a full 4 post rig to support the the whole bus. Our front bags will attach to the two point where you have those 2 jacks and the rears will tie in to the tag axle mounting location.

The owner of the bus claims it weighs 28,000 lbs as it sits. Seems light to me.

How much droop and articulation are you getting out of the stock suspension? This is Pirate after all...

 

[JNHEscher]

FirstRam said:
How much did this bus weigh in stock form? I was handed a project at work yesterday which will involve using airbags to simulate a bus accident. We have to violently rock the bus side to side, spilling the contents of the overhead storage compartments.

The bus is a 50 seat 1988 MCI. I plan to remove the tag axle, shocks and sway bars and leave the bus sitting on its tires. We just don't have time to build to build a full 4 post rig to support the the whole bus. Our front bags will attach to the two point where you have those 2 jacks and the rears will tie in to the tag axle mounting location.

The owner of the bus claims it weighs 28,000 lbs as it sits. Seems light to me.

How much droop and articulation are you getting out of the stock suspension? This is Pirate after all...​

I wish I had a specific number for you. Our plate says 22,000. I unfortunately forgot to take it to the scale right after we got it registered. The rough tally from the scrap runs was a touch over 5,000 pounds in stuff we removed and that doesn't include a heap of plastics that were trashed. I'm thinking you have a 45' D series bus because of the 50 seats, but I'd have to check what year those started. Our C3 had 45 or 47 seats and is a 40'.

Funny you ask about articulation. I've wondered that myself and happened to be thinking about flexing the steer axle as much as I could while staring at the new hole in the pit last night. With the four jacks under the front, I can tilt the axle to get wheel travel and put my digital level on the beam. I think I'll do that to get some numbers for Pirate.

I would love to see this test and the results if you're allowed to share it. Rollover is something I've been keeping in mind. Much of what I'm modifying/installing in our bus is meant to lower the center of gravity and keep weight below the roll center.

 

[JNHEscher]

Did it. I couldn't find my digital level, but a dial is much better for eyeballing dead zero anyway as long as the dial is accurate. I got the front of the bus as level as I could tell off the floor.

The bus is lifted just high enough for the drooped tire to barely spin on the dirt. There's an inch or so depression in the ground from each tire, so I figure this balances out to tire squat if I were able to do this on a hard surface. There's roughly 12" of wheel travel as measured from the ground that hasn't been pressed, so same theory of 1" or so of tire squat since measuring from the dip in the ground from the tire would be cheating it.

Checking axle angle at the top of the beam, it sits right around 9.5 degrees. The bus is still sitting in the articulated position and I'm looking at it from in the house. For a brick of a people hauler, it actually looks kind wild. As shown, the link bushings restrict any further motion. The raised side is against the bump stop. The shocks also limit travel as I've seen on the drive axle.

So there you have it, Pirate. Rock crawler stance on a coach bus steer axle. I'll test out the rears soon. How about a lift kit and some light bars?

 

[JNHEscher]

Java said,

All the flex

Now how much more comes out of the chassis??

 

[JNHEscher]

Java said:
All the flex

Now how much more comes out of the chassis??

Sent from my SM-G950U using Tapatalk​

Not too much more. Cleaning out a bit more of the layered sheet metal today so I can take care of oxidation in tight spots.

 

[JNHEscher]

My intense Google searching last night pulled up Team Money Pit's post about a build part-out that had three of the exact AxelTech independent units at a great price that I've been lusting after and I just so happen to need three units. This post was over a year ago. Bummer. Carry on.

 

[JNHEscher]

bigun said,

So did you check to see if axles were still available or just Assume they weren't?

 

[JNHEscher]

bigun said:
So did you check to see if axles were still available or just Assume they weren't?​

I asked, but fully expect to never receive an answer because they were posted over a year ago and the prices on all the parts were too good to pass up. Couldn't find any indication that anyone had taken interest in the AxleTechs, so who knows.

I called the guy in Arkansas that had some and he said he sold them. He does have two wide 4000's. Those 4500's, though, would be freakin' awesome.

 

[JNHEscher]

bigun said,

JNHEscher said:
I asked, but fully expect to never receive an answer because they were posted over a year ago and the prices on all the parts were too good to pass up. Couldn't find any indication that anyone had taken interest in the AxleTechs, so who knows.
.​

They do have a Book of faces page, if you know someone who has one you might try to contact them you never know.

 

[JNHEscher]

bigun said:
They do have a Book of faces page, if you know someone who has one you might try to contact them you never know.​

That's where I asked. I think it's been two or three months since they (he) posted. I'll pester people until somebody fires back.

Edit: Matt got back to me. They did sell. The hunt continues.

 

[JNHEscher]

FirstRam said,

It's hard to tell from your pictures how complicated these buses are. We just gimbaled one for a show I'm working on and holy shit they are complicated and crowded. Everything you've done will make it so much easier to repair in the future, if needed.

 

[JNHEscher]

It's hard to tell from your pictures how complicated these buses are. We just gimbaled one for a show I'm working on and holy shit they are complicated and crowded. Everything you've done will make it so much easier to repair in the future, if needed.​

Lol you feel my pain. Bet this thread is a pot of gold for a shop learning every nut and bolt. Just yesterday I was thinking about moving my jacks to the rear so I could show off the drive axle articulation. And definitely, I'm making this beast a drop in the bucket to maintain at any time and any location.

You have me really curious, now. Gimbaled? On which axis/axes? This is going to be wicked cool to watch, whatever you guys are working on.

 

[JNHEscher]

I think I want your job. And those convoluted bags. A setup like that would help me out a lot right now. I've used smaller air bags to lift cars before, but nothing of this size and weight. Air sure beats pumping a bottle jack 177 times to reach full height.

 

[JNHEscher]

FirstRam said,

30,000 lb bus, 25 people onboard pushing 90 psi with a diesel compressor. It was quick to say the least. Sorry I can't post video, even the pic's are pushing the NDA.

It was intimidating seeing the tires lift off the ground!

I never really appreciated the work you've put in until I had to work on this thing. What were the designers thinking, it's almost a non serviceable item.

 

[JNHEscher]

FirstRam said:
30,000 lb bus, 25 people onboard pushing 90 psi with a diesel compressor. It was quick to say the least. Sorry I can't post video, even the pic's are pushing the NDA.

It was intimidating seeing the tires lift off the ground!

I never really appreciated the work you've put in until I had to work on this thing. What were the designers thinking, it's almost a non serviceable item.​

No worries about video. Don't want you to get in trouble. You're making me super anxious to get to work on the rear. Particularly if I ever get ahold of some AxleTech axles to swap in. The disc brakes look a hell of a lot easier to service. You're right about everything being crammed in. I couldn't reach much of anything in the engine bay until I started to cut stuff out.

 

[JNHEscher]

FirstRam said,

Nasty too, normally functioning Detroit Diesel FTW!!

 

[JNHEscher]

FirstRam said:
Nasty too, normally functioning Detroit Diesel FTW!!​

Part of the club. Most say it can't be done, but I'll be hard at figuring out what it will take to make ours free of ink dribbles.

 

[JNHEscher]

We are going with 455 super singles. Doing so provides an extra 5" between the tire sidewall and edge of the frame, making way for the battery cables. Bit of a toss-up because if duals ever need to go back on, there lies the battery cable problem again. But , like has been mentioned, batteries are constantly changing right now and this problem of mine could be entirely nonexistent within a couple years.