Hello gang, I recently got all my air bags replaced on my MC-8. Prior to that, it usually took a few hours for the air bags to bleed out whenever I turned everything off. Now that I have new bags, I have noticed that the bags bleed out a lot faster. I still maintain air when driving so no issue, I'm just wondering if the new bags are adjustable or if things are now working like they should be.
Now when I turn everything off at a campground for example, I better not take too long in getting the blocks underneath b/c they will drop within an hour. Just trying to figure out what normal is and if I should take it back to get looked at or adjusted.
Does not sound right. Mine will stay up for weeks. Maybe some leaks from the air line connections or the bags haven't seated on their seals.
Where the bags plated or was it kept original with the MCI air beams ?
Quote from: Lee Bradley on December 06, 2018, 07:03:04 AMDoes not sound right. Mine will stay up for weeks. Maybe some leaks from the air line connections or the bags haven't seated on their seals.
Yeah, in my experience, anytime you do any work on air lines and associated components, you need to be sure that you have everything perfectly tight and leak free -- then go back later and trace everything down to find the items that are leaking. I don't know if things "take a set" or loosen up, or if I just missed them the first time, but there seem to be more leaks a week after I worked on the air system than two hours after I did. The factor of the large-diameter seats on air suspension bags can be an issue, too.
Quote from: luvrbus on December 06, 2018, 07:39:44 AM
Where the bags plated or was it kept original with the MCI air beams ?
They were plated. Something that the other replies are confusing me is that even before my air bags would air out once I turned everything off. I'm not sure if they have a different model or not but it's my understanding that they are suppose to air down especially the 74 MCIs.
Is the bus dropping on all 4 corners evenly or 1 corner then dropping on the others ?
All is evenly. I've only gone camping once since replacing the airbags and I always put blocks underneath 2 in the front and 2 in the rear and it was the first time I was perfectly level. I don't know if that was mere coincidence or not. I'm maintaining air while driving too.
It is probably the check valve then at the auxiliary tank where the bags get the air supply from.my MCI 8 would hold air for weeks
Quote from: luvrbus on December 06, 2018, 09:17:01 AM
It is probably the check valve then at the auxiliary tank where the bags get the air supply from.my MCI 8 would hold air for weeks
Is the check valve near the front fender? If not are there valves at the fender b/c I can hear air coming out near the passenger front tire.
My MC-5C will hold air in the suspension for at least a week, even with zero pressure in the system. Check valves in the leveling valves, I believe.
Not sure about the MCI, but in the GM aren't the check valves in the leveling valves?
I've got new leveling valves all around, and after fixing a few minor air leaks my bus will stay aired up for months when parked.
I know that there are differences between MCI and GM buses, but dropping down in an hour seems way to quick.
I talked to my mechanic and he was going to have me order leveling valve for the drive axle left and right but when I told him that I heard air coming out near the front tire, he said to hold on. So I'm going to drive it over there Saturday for him to look at it.
On a MCI 8 it is going to depend on the unit number, MCI changed the air system on the 8 as often as people change socks mine had a check valve at the auxiliary tank that feed the air bags it went bad I could stand and watch the bus settle down on the stops in a few minutes
No MC8 is intended to settle when shut off.
Unscrupulous mechanics know they can empty a newbie's wallet, and leave him feeling very supported...
Others have no problem letting you pay for their own education on buses...
Why the hell would it be acceptable to pay someone to improve air integrity and get the coach back with worse air integrity?
Get your radar spinning, you paid for a job to be done that wasn't.
Take a grain of salt or not, I'm a cynical old fart, legitimately earned... seen and heard way too much of this abuse of newbie's who can't defend themselves.
Happy coaching!
Buswarrior
On your MC8 if you have an AD2 air dryer( long white or blue cylinder with a purge valve in the middle of the bottom plate. It will sometimes stick open or get something stuck part way and keep leaking air when compressor is not running it will leak down pretty fast through that valve or no pump up when needed.
At the top driver's side big pipe that comes out has a big nut also. Inside that nut is a check valve ball type that will let air through if it is not sealing. You also have a airbag filter between the 2 big tanks in the wheel well hanging down. Make sure the valve on that filter is closed (cross ways to the pipe it on) Do not open that filter because they are generally rusted at the 4 corner bolts and will break if you mess with them. Don't ask me and three other people I know, how we know that) :)
Also at each connection to your airbags from your supply side at the hose end there is a small filter in that nut and needs to be cleaned if you never have just take it out and clean or replace them (Napa)and make sure those ends all 4 in back and 4 in front are tight and not leaking air. HTH
This guy has a unique bus all 3 axles bleeding off level and the bus airs up
Yep thats why it maybe at the check valve before the accessory tank off the airdryer or bag filter. Happened to us. :) ours are independent now and stay up until I want them not to be, LOL
In the old days when we had leveling valves it would bleed down in 2 hours.
You will never know with the air schematics for his unit if it was holding air till he had the air bag replaced it has to be the install I would think,with the air beams out of play they do drop faster with a small leak
Luver, I wasn't holding air that long before bag replacements but I think it would take a good 4-5 hours before the axles rested on my wooden blocks. Now it's airing down within an hour.
I'm going tomorrow to the mechanic and having him look at it. I will let you guys know what comes from it. I appreciate all the responses.
I never knew that the "norm" was these busses can hold their air for days/weeks before. Even when my uncle had this bus it would air down when shutting off fairly quick. Guess he never cared that much to see where it was coming from. He did tell me today that it use to air down uneven but I never experienced that except that it seemed the front would take a little longer than the back but I only knew that b/c of the space between axle and block. I couldn't tell by looking at the coach.
So he's the one we are visiting for xmas in Texas and he recently bought a leak detector so maybe we will check that out in between sips of bourbon?
If it was the Job then maybe he tightens them up and it stops the leaks. If not refer to previous post. :)
Did they have this "feature" on models with handicapped models? Or just kneeling?
How a coach lowers to assist customers to board depends on its vintage and manufacturer.
Popularly, in a high floor coach, the front suspension lowers, so the step-up height is less.
Many different vintages of valving since this started in the mid 80's, earlier and more so in transits. Slow, fast, reliable and less so...
The low floor bus world, some are lowering the whole curb side of the bus, so it tilts to the right in North America, front and rear suspensions involved.
Happy coaching!
Buswarrior
It's the shop problem anyways we cannot fix it here ,it's not clear if just the auxiliary tank is draining or the complete system, a bus with a tag dropping level is something rare
Maybe there is Delo 100 in his airbags? :)
Turns out there is about a 3-4 inch area air is leaking out on the front right air bag which I assume is where the metal cap and bag meet. That's the hope anyway and that it's not a bad air bag.
He was only able to look at it briefly but I should know more this week.
Quote from: Branderson on December 11, 2018, 09:35:35 AMTurns out there is about a 3-4 inch area air is leaking out on the front right air bag which I assume is where the metal cap and bag meet. ...
Hey, Brad. I'm pretty sure you're describing what the call the "seat". On many bags, there is a radiused cup in the metal plate that the matching edge of the rubberized bag is meant to seat down into. Sometimes, they come unseated because the metal is bent or the rubber part is torn or worn (in which cast the unit is done) but other times, the rubber just needs to be seated back on the metal. If you have someone who knows what he's doing, he'll be able to sort the difference out quickly.
just wanted to follow up. I picked up the bus today. There was a small leak coming from the front right air bag. The metal plate was a bit corroded and had a very small crack in it so the mechanic fabricated another plate and so far so good. I just got it home and it's been an hr and it hasn't lowered at all and I can't hear the air coming out anymore.
I'm sure it will bleed out in a few hrs or so unless it is better now than it was before I got the air bags replaced.
Cool a followup. That doesn't happen very much thank you for letting us know. :)
Quote from: Branderson on December 15, 2018, 01:37:14 PM... it's been an hr and it hasn't lowered at all and I can't hear the air coming out anymore. ...
:)