| Author | Message | ||
| Busfool (Chuck)
Registered Member Username: Chuck Post Number: 58 Registered: 12-2004 Posted From: 216.208.52.52 Rating: N/A |
The last time I started my mci9 the front did not lift on both sides . I did not here any air leaking and have a suspicion it may be one of the valves that controls the air. Is this a major project to fix on your own? Do I need a new valve or can the old one be re worked some how? Has any one had the pleasure of fixing this problem and how did you go about it? Your help would be greatly appreciated.Chuck | ||
| Bob greenwood (Bob_greenwood)
Registered Member Username: Bob_greenwood Post Number: 175 Registered: 7-2006 Posted From: 4.227.119.155 Rating: N/A |
probably a little spray of liquid wrench & some wiggleing would fix ...BUT....you have to do some SERIOUS blocking up of the bus before you get under there | ||
| JR Lynch (Njt5047)
Registered Member Username: Njt5047 Post Number: 72 Registered: 7-2006 Posted From: 69.132.238.127 Rating: |
Air up the bus, and place good quality large wood blocks beneath the posts located between the tag and drive axles. Take up all the extra space with plywood shims. Let the air out and the bus will settle down on the blocks. Purge all of the bus air before removing any air lines. You'll need to attach shop air to the coach so that you can diagnose the problem. Place a jack under the jack point located on the front of the drive axle suspension and take the weight off the affected side drive wheels. Only takes an inch or two. Don't "raise" the wheel...just enough to clear the ground. Make sure that the bus is chocked and that the blocks are on solid ground. Remove the wheel lugs and work the wheels off the hub. If you have steel wheels, they are heavy and may require two people to handle safely. You will be looking at the leveling valve. Check the linkage and verify that the link isn't disconected or damaged...or fallen off the leveling valve. Leveling valves are easy to replace IF you can safely jack the bus and remove the wheels. Leveling valves are cheap too...about $45 to $75 each. You state one side isn't coming up...that would indicate the rear low side leveling valve has failed. Probably. Regulator failure, linkage, air leaks (you've ruled this out), could all cause the side to sag. Read a manual on adjusting the leveling valve. Dinking with leveling valves on an aired up bus is dangerous. Move the lever down and the bus comes down. The leveling valve will have to be adjusted once installed. The low side should match the other side once inflated. There is a standard dimension between the body and axle. I'll see if I can look it up for you. Remember that if the drive axle isn't level, the bus won't be level...but the distance from axle to bus body should be equal. The leveling valves do not "level" the bus...only maintains level relative to the drive axle. If you don't have a good 3/4" impact...preferably a 1" impact, a torque wrench for the lugnuts, and a right good bit of strength, you may not wish to tackle the job. It wouldn't be a major repair at a facility that has a pit. If you feel comfortable doing the job, might as well buy (you may have all the equipment to do this job?) the tools to do the job. You'll have other occasions to remove the wheels. While it's jacked up, may as well adjust the tags and drive slacks. Keep us posted on how this goes! Best, JR | ||
| Kyle Brandt (Kyle4501)
Registered Member Username: Kyle4501 Post Number: 200 Registered: 9-2004 Posted From: 65.23.106.193 Rating: N/A |
When I replaced my rear leveling valve, I used a shovel to help make room for me to crawl under. Once inbetween the rear wheels, I had plenty of room, but our buses are different makes.... One thing I'll recommend is to not get in a hurry & plan on several trips to get air fittings. I had what I thought a good selection & it still took 3 trips to the store (they never seem to have the fitting you need, so you have to 'adapt' & that causes other opportunities). The replacement valve was slightly different than the one on the bus & some of the existing pneumatic lines under there were in desperate need of replacement. It was an easy job that I enjoyed (- Oh yea, Make sure you have the new valve plumbed in correctly or you will be back under there!) Good Luck! | ||
| Bryce Gaston (Busted_knuckle)
Registered Member Username: Busted_knuckle Post Number: 268 Registered: 1-2006 Posted From: 65.7.60.135 Rating: N/A |
I'm confused as to why we're telling him about working on the rear. As I understand the original post it's the front axle he's eperiencing trouble with! Chuck start your bus, and build up air again. Then if the front still doesn't come up, pull the front tires up on some boards/ramps. Then place blocks under the front jacking points and support the body, hook up a source of air! Now you can get under it, and you'll find a small linkage between the leveling valve to the front axle. Spray the valve with WD40, and take the linkage loose and work it up and down! Now push the linkage up and hold it a minute the bus should try to raise off the block under the body. If it does the valve is ok, if it doesn't then the valve is likely bad! Now if it raises but not evenly it could still be a bad valve or trash in it, or the line! Let us know what ya find an if needed we'll help ya go farther. BK | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 1688 Registered: 1-2001 Posted From: 75.108.82.163 Rating: N/A |
He indicated the bus did not lift in the front on both sides. If I am not mistaken it is a three point leveling system with only one valve in front and two in back. The two in back maintain rear height as well as side to side leveling. Richard | ||
| David (Davidinwilmnc)
Registered Member Username: Davidinwilmnc Post Number: 136 Registered: 7-2005 Posted From: 152.20.216.103 Rating: N/A |
I don't have a 9, so I'm not sure, but... did the NJT's have a kneel valve like most transits? If so, that could be the problem. If it's a rear valve, they are fairly easy to replace. I replaced the driver side rear valve a couple of months ago along with the inversion valve. While you're in there, clean things up a bit and check for any other leaks. That's how I found my inverson valve leak - the body of the valve had a big crack in it. I got my leveling valve from Luke, by the way. Follow all the safety guidelines JR gave above! David | ||
| Bob greenwood (Bob_greenwood)
Registered Member Username: Bob_greenwood Post Number: 180 Registered: 7-2006 Posted From: 4.227.112.171 Rating: N/A |
I thought it was two in the front & one in the back...I think he needs to be working on the front | ||
| Busfool (Chuck)
Registered Member Username: Chuck Post Number: 59 Registered: 12-2004 Posted From: 216.208.52.96 Rating: N/A |
the bus did lift on the back on both sides it was the front on the passenger side that did not come up?I think my first effort will be to try what busted knuckle suggested since it seems the easiest.Thanks Busted | ||
| JR Lynch (Njt5047)
Registered Member Username: Njt5047 Post Number: 75 Registered: 7-2006 Posted From: 69.132.238.127 Rating: N/A |
Richard's correct. An MC9 has one leveling valve in the front that sets the front height only. The rear has two leveling valves that set both rear height and lateral leveling. A "tripod" if you will. While it's true that NJT MC9s have kneeling valves, that would not affect "lean"...only up and down. The coach could have two problems which would present as a low front height, related to the front leveling valve...and a lean that would be due to rear leveling valve. Lean could be caused by either too high, or too low, leveling valve operation. In any event, on an MC9 (all years), the front suspension does not laterally level the bus. Kneelers should be removed from the circuit. They are prone to sticking and bleeding off a lot of air...or they won't recover and leave you with the front frame 4" off the ground. This is a hoot to drive! Kneelers are usually only found on MC9s that were used in Metro systems. If you want to lower, level, or raise the coach for leveling in campgrounds or such, take control of the airbags manually. If the coach leans wrongly laterally, the rear leveling valves should be evaluated. If the front ride height is not correct, when the bus is aired up and otherwise level, the front leveling valve is probably at fault. Some combination of both are possible. On an MC9, the rear rubber wheel well moulding shouild be about 5" to 7" above the drive axle tires when viewed horizontally. The front will be a little less, about 4" to 5" above the steering tires. Remember that the bus body levels laterally only to the drive axle. If one drive wheel is in a low spot, the bus will list as it levels only to the drive axle. The tags don't enter into this equation..they are set to a specific pressure (35 lbs) and don't have leveling valves. They remove approx 2K lbs from the drive axle. Good luck, JR | ||
| t gojenola
Unregistered guest Posted From: 69.178.30.245 Rating: N/A |
Before you spend too much time and money on percieved repairs - particularly if the bus has not been moved for awhile - you should take it out for a short spin. Oftentimes just moving it will get the leveling valves working and correct the problem. tg | ||
| Steve N. (N4rsn)
Registered Member Username: N4rsn Post Number: 94 Registered: 2-2005 Posted From: 70.248.144.119 Rating: N/A |
My GMC 4106 did the same thing. It would not come up on the passanger side. I ran it up on some ramps I made, and crawled under it, with shop air to the air system. I found the rear air bag, on the front, had a tiny hole in the back side of the bag. Changed the bag, and now she comes up just fine. These air valves, only let a small amount of air through at a time. If they adjusted the height fast, it would be adjusting constantly, while you are traveling. Steve | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 199 Registered: 11-2005 Posted From: 63.97.117.14 Rating: N/A |
tg is right, my 4104 does the same thing once in a while but it always comes up after a few minutes. It isn't always on the same side or end either. | ||
| Bryce Gaston (Busted_knuckle)
Registered Member Username: Busted_knuckle Post Number: 275 Registered: 1-2006 Posted From: 74.226.122.19 Rating: N/A |
Hey these ol' girls get tired too! Once in a while I have trouble getting up off my butt too! LOL! But air don't help me! Did some one say free cold beer? Where? See ya! BK |
