changing out MCI air springs choices

bevans6 · October 14, 2009, 07:13:23 AM

Hobe's post has me thinking about this, as he hoped and expected it would, so thanks!

My MC-5C is from Arizona and has had almost no service in the "salt belt". That means, thankfully, that the stock air system, with what look like the original springs, is all present and accounted for. While the springs show pretty consistent checking all over, the suspension, including the stock air beams, doesn't seem to leak down to a measurable degree even over 20 or 30 days. It just sits there, and the distance over the bump stops doesn't change. So that is good news, right?

But the bags are checked all over. Even if they don't leak, they are pretty old. I like to maintain stuff that can leave me stranded, so I want to think about changing these out. What I'm afraid of is making things worse instead of better - is there a chance that by changing them I could end up with a bag that doesn't seal to the beams as well, or just has a "normal" leakage that I don't suffer from now? Is this a legitimate case of "if it's not broke, don't fix it?"

Also - I find the ride of my bus harsh. It reacts a lot to minor road irregularities, like the springs are too stiff for the weight on them. I haven't managed to get it weighed yet, maybe this weekend as I am going on a fairly long trip and may pass an open weigh station. I read that rolling lobe springs are an upgrade in ride quality compared to the convoluted two lobe bags I now have. Does anyone know if that's true compared to a stock MCI setup including the air beams, or just compared to sealed off standard bags? Can you install rolling lobe bags and keep the air beams operational, or ist hat a bad idea?

Thanks for the advice, as always I am trying to learn as much as I can before I make a decision that involves a great deal of personal effort and sliding around on the ground breaking fingernails and getting all dirty...

Cheers, Brian

Busted Knuckle · October 14, 2009, 07:22:20 AM

Brian you can weigh it at any major truck stop! FWIW

BK

Tenor · October 14, 2009, 07:25:42 AM

Hey Brian,
Once again I was in the same boat as you! My bags were very cracked, yet the front never came down. I could tell that the rear leveling valves leaked, so I took a chance and replaced all of the bags using the original system of air beams. It was quite straightforward. It worked perfectly. No leaks (although the rear continued to lose air until I replaced the leveling valves). The ride is firm, but the side to side motion is minimal. I have read that plating the air beams can lead to a harder ride, but I'm not so sure. I had a 4905 with standard air bags and I can't say it rode any harder than my MCI. Although, perhaps that's comparing apples to oranges. I wish I knew anything about the rolling lobe, but I'm sure someone else will chime in. Either way, replace your old bags. That's not a repair to make on the side of the road!

Glenn

bevans6 · October 14, 2009, 07:30:11 AM

BK, believe it or not, I've owned the bus since June, I've put a tank and a half of fuel through it, I've driven about 600 miles so far, and I have not driven past a truck stop with a "Cat" scale, or driven past a Provincial weigh station that had left the scales turned on. I've pulled into a few that were closed, but the scales were turned off. I haven't even driven past a Provincial truck weigh station that was open! I must be leading a very sheltered bus life! This trip I am going to Buffalo via a major highway, then to Watkins Glen NY on non-interstate, so I hope I'll pass something that works.

Brian

belfert · October 14, 2009, 07:43:41 AM

I don't own a MCI, but I have read thousands of posts here and over on BNO.

The consensus seems to be that air beams that are not leaking offer the best ride. Rolling Lobe airbags are generally used when the air beams have been blocked off. Maybe the 5s don't have air beeams, but I know newer MCIs at least up to the 9s had them.

Busted Knuckle · October 14, 2009, 07:45:08 AM

Ah, I see say the blind man! I actually forgot you were from the "north" Aye? In the states almost all large truck stops have a scale. Not all have CAT scales (Flying J has "J Scales") but most have 'm of some brand 'er another!

BK

Ed Hackenbruch · October 14, 2009, 08:36:19 AM

Brian, the 5's have air beams. I had one bag that started leaking a couple of years ago so i ended up replacing all of them and kept a couple of the old ones that were in good shape as spares. I can also set each bag to whatever pressure i want, up to 100lbs, and usually run with the fronts at 80 and the back at 70 which keeps my towbar at the right angle between the bus and jeep. I think the ride is just fine but then this is the only bus i have ever driven.

bevans6 · October 14, 2009, 08:43:55 AM

As I said, maybe not so clearly, in my original post, my bus has air beams that are in perfect shape. Maybe I can restate my real questions:

If my air bags are checked all over but not leaking at all, should I change them anyway?

If my air beams are in perfect order, should I keep the stock setup (dual lobe bags and the beams) or would rolling lobe bags give a better ride?

If I go to rolling lobe springs, do you have to seal them off or can you retain the air beams and have the rolling lobe bags work with the air beams?

Thanks for all the feedback, I appreciate it.

Brian

redbus · October 14, 2009, 09:21:45 AM

Wow Ed.70-80#. I must not be running enough air in mine. I run 55-60# front and rear. I will try to pump it up some and see how it rides when I leave this J** (dirty word) in Kansas.

bevans6 · October 14, 2009, 10:05:15 AM

I do know this about that. The point is not how much air you run, it's if the suspension is at it's design ride height (or at some other height that makes you happy). What is right for one bus may not be right for another. Selecting your ride height and suspension pressures based on the tow ball height isn't necessarily the way I would do it, but then I have an adjustable height hitch draw bar, and maybe doing it that way ends up perfect for things like driveshaft angles too, who knows... If you know your suspension pressures, that implies that the stock leveling system is disconnected. I have read, I forget where, that the maximum pressure recommended for air bags is 80 psi. I don't know if that is sitting still, in a campground, or on the road, though, and I don't have the cite, although I suspect it was in relation to Sean's leveling system.

Brian

redbus · October 14, 2009, 10:23:42 AM

I did set mine up for ride height and ride comfort(nice soft ride) But if something works better for someone else I am willing to try it.Or at least a modified version. 5# up or down makes a big difference in ride quality.

bevans6 · October 14, 2009, 10:26:34 AM

For curiosity's sake, if 5 psi makes a noticeable difference in ride quality, have you ever noted what difference in ride HEIGHT 5 psi makes? That might be interesting to know...

Brian

lostagain · October 14, 2009, 11:41:55 AM

Yes, replace your air bags. Is is easier at home than on the side of the road.

Stay with the OEM setup: convoluted bags and air beams. You can go to rolling lobe bags when your beams start leaking. My 52 year old Courier 96 doesn't leak yet, and it has seen a lot of winter. Rolling lobes are plated top and bottom, so would not work with air beams. I can't tell from first hand experience, but air beams and convoluted bags have a lot more air to cushion your ride than rolling lobes alone. So I would stay with the OEM setup as long as you can.

JC

Tom Y · October 14, 2009, 03:13:57 PM

Brian, My beams are good also. But if you ever get at the top (under the floor ) you may want to wire brush and paint. That is were the rust is at. Change the bags now if you can. A lot easier at home. Tom Y

redbus · October 14, 2009, 04:53:25 PM

I change the pressure while driving so i don't know how much the height changes.But on a rough road you can let out a few pounds (3-5)and help the ride or in wind you can add a few pounds to help stabilize.