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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: BusCrazyinFL on January 26, 2012, 05:34:51 AM

Title: Prevost AirLock?
Post by: BusCrazyinFL on January 26, 2012, 05:34:51 AM
I am a locksmith by trade and have a customer that has a 1995 XL and is living in his bus full time. I have made keys for all the locks because he has lost them more than once. He called me the other day because he was locked in his bus. When I got there, I pulled the handle from the outside and the door opened. I didn't see anything wrong with the door mechanism. Next day he calls me out again saying the same thing happened. I went back out but by the time I arrived the door again would open. It seems that when he starts his bus in the morning, this lock automatically engages. It's apparently a safety feature while the bus is running to keep the door sealed and air-tight. The problem is the cylinder is not releasing until all the air is out. I'm thinking that the air cylinder is not functioning properly. Has anyone run into this problem? Does he need to take it to Prevost or is there something I can do to correct this problem? Btw, this bus has been sitting for a couple of years without being used.
Title: Re: Prevost AirLock?
Post by: bevans6 on January 26, 2012, 05:48:39 AM
MCI's have an air dump valve for the door, located under the dash and with a cable or external push device.  It dumps the air cylinder supply only.  I would look for the inside control for that.

Brian
Title: Re: Prevost AirLock?
Post by: Ace on January 26, 2012, 05:56:30 AM
Manny, mine is the same way and I also have a red switch that I must turn to release the air to oPen the door or once the door is closed I have to turn the switch so it will seal tight!
Title: Re: Prevost AirLock?
Post by: robertglines1 on January 26, 2012, 06:07:21 AM
white is the air line color for door lines. look in front bumper/spare tire compartment for electric activated selonoid door release valve. If Liberty or some other pro conversion contact them. They change Prevost controls quiet often. Outside key probably activating Elect /air release selonoid to door close cyl.
Title: Re: Prevost AirLock?
Post by: luvrbus on January 26, 2012, 06:09:04 AM
Manny he has to have a 24v electric supply to work the door lock does he have the master switch off or on then he could have a bad solenoid

good luck

Title: Re: Prevost AirLock?
Post by: BusCrazyinFL on January 26, 2012, 06:09:37 AM
I looked for a switch but could not find one, and the owner didn't know anything about a switch. Where would it be? Funny thing is, he's been living in this bus for more than a year and this is just now becoming a problem.
Title: Re: Prevost AirLock?
Post by: BusCrazyinFL on January 26, 2012, 06:13:10 AM
Cliff, you might be right. That was one thing I was thinking might be wrong. I'll go back and check these things out. Last time I was there I didn't have the time to get into it too deep and wanted to do some research beforehand anyway...Thanks everyone. If I can't fix it I'll send him to Central FL Bus.
Title: Re: Prevost AirLock?
Post by: wg4t50 on January 26, 2012, 06:15:53 AM
My MCI7 had the air lock latch, it is controlled by a micro switch that only locks when the master switch is on and the door handle is fully over center.  Just unlocking the door handle opens the micro switch IE door unlocks.
Very Simple
Title: Re: Prevost AirLock?
Post by: luvrbus on January 26, 2012, 06:21:35 AM
Manny check the voltage at solenoid and relay lube all joints and some models have a module to control the door probably the relay went bad

good luck
Title: Re: Prevost AirLock?
Post by: Ace on January 26, 2012, 07:30:01 AM
My guess the  Norgren valve went bad! Mine did and it did the same thing!
Title: Re: Prevost AirLock?
Post by: Boomer on January 26, 2012, 09:04:01 AM
I always wonder why these guys that have problems don't make their first call to the Prevost regional tech rep.  They will answer the question immediately, for free.
Title: Re: Prevost AirLock?
Post by: luvrbus on January 26, 2012, 09:14:12 AM
Mark they get pretty lost sometimes on the conversion shells with converters re locating things I been talking to one for 2 days bless his heart he has no idea what going on with a Marathon neither does Marathon lol

good luck
Title: Re: Prevost AirLock?
Post by: artvonne on January 26, 2012, 09:33:58 AM
Quote from: luvrbus on January 26, 2012, 09:14:12 AM
he has no idea what going on with a Marathon neither does Marathon lol

good luck

    Good thing NASA didn't work that way during the Apollo 13 deal, eh?

    I plan to remove the air lock on my 5. I just need to find a good door latch mechanism so it clamps shut good and tight.
Title: Re: Prevost AirLock?
Post by: Ace on January 26, 2012, 09:37:00 AM
I agree on calling the reps but another thing is if you understand how the door works you would love it! Mine used to pop open at will and at 70 mph that ain't funny! I took the time to learn it and now I wouldn't have any other!
Title: Re: Prevost AirLock?
Post by: artvonne on January 26, 2012, 02:27:55 PM
What I see on mine is that while the air lock works quite well, it makes the entire stair well 4 inches narrower. If the air lock was gone I could open the stairwell up the entire width. One thought I had was putting the air cylinder on the wall and making it suck the door shut from there. Another thought was to put the cylinder on the door itself. I think it would be simpler to lose it all together and use some decent latching mechanism that doubles as a lock.
Title: Re: Prevost AirLock?
Post by: bevans6 on January 26, 2012, 02:37:44 PM
Art, if you remove it put it in a box and send it to me.  I retrofitted a saloon door in place of dual doors, and the lack of the lock is a major problem when it comes to keeping the door tight on the road.  Major air pressure trying to open it.  Very hard to come up with a mechanical design that does what the air lock does (including remote control).

Brian
Title: Re: Prevost AirLock?
Post by: artvonne on January 26, 2012, 04:50:51 PM
  Brian, if I figure it out you have first dibs on it. It wasnt working when I drove it home, and the linkage rod was disconnected, I pulled it shut with a ratchet strap. Your correct there is some serious air pressure trying to suck it open.

 

 
Title: Re: Prevost AirLock?
Post by: wg4t50 on January 26, 2012, 05:49:15 PM
I am with the crowd that likes the air latch, IF you understand it and now it works, it is a beautiful contraption that works, for sure no one is going pull the door open uintil you release it.  What is not to like ?  (MCI 7 model)

I had the service manual set for the coach, MCI convers the items fairly well, so it was a simple thing to figure it out, never had a problem.
Title: Re: Prevost AirLock?
Post by: Ed Hackenbruch on January 26, 2012, 05:51:03 PM
Yup, i sure like mine too!   ;D
Title: Re: Prevost AirLock?
Post by: RJ on January 27, 2012, 12:30:31 AM
Paul -

Before you go pulling the air lock on your 5 to widen the stairwell, take another look at where on the DOOR the lock grasps.

I think you'll find that you'd really not gain much by removing the claw mechanism, and trying to yanquiengineer a replacement might be time better spent elsewhere.

As much as I'm a GMC guy, I'll be the first to admit that MCI's door air lock is one of the "better ideas" in the highway coach market.  There is a world of difference in the front noise level around the door because of it. 

FWIW & HTH. . .

;)
Title: Re: Prevost AirLock?
Post by: Ed Hackenbruch on January 27, 2012, 04:42:30 AM
And coming from RJ, that is saying a lot! ;D