| Author |
Message |
kingfisher
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 02, 2005 - 11:44 am: | |
4104 air builds to 115 lbs,bus sits for several hours,rear drivers side goes down to almost the ground.if you build the air up again and leave running bus maintains height,turn it off will go down again after time.anyone got a clue.thanks pat |
Tim Hoskinson (Tdh37514151)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 02, 2005 - 12:57 pm: | |
Could be several causes. A fitting on a air line the line its self the bag could be dry rotted and have a crack in it the air beam could have a small hole. But the most common problem is the leveling valve leaking a bit. If you air up the bus then shut it off and walk around the bus listening carefully you should hear the leak near the rear wheels of the bus. This will tell you If its a valve , line to the bag, the bag,or the air beam leaking outward. If you can detect no leaks it can be that the leveling valve is allowing the pressure to go back into the system after the air system has leaked down through other small leaks elsewhere in the system. When the system bleeds down if a leveling valve is trying to take on air and there is none in the system the bag will deflate. This is just some suggestions from what experience I have had with my 4104. Best of luck to you . Tim |
Stan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 02, 2005 - 1:14 pm: | |
Tim: If a leveling valve is working properly, the bag cannot put air back into the supply line.
Kingfisher: Look back to the thread on July 01 headed 'Leveling Valves' and you will find more info and if you use the seach function on the left side of the screen you will find a lot of info. |
kingfisher
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 02, 2005 - 2:35 pm: | |
thanks to those with the info I guess its off to the shop for the old girl. thanks again. |
Tim Hoskinson (Tdh37514151)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 02, 2005 - 10:04 pm: | |
Hi Stan I guess I wasn't very clear on my point on the leveling valve. Your wright if the check part of the valve is working propery it will not deflate. What I was trying to say was the valve could be at falt and not leak outwardly but leak back inside. In this case listening for the leak may not tell you anything. I went back and looked over what I had written and I didn't describe things as well as I should have. Sorry. Tim |
Tom Caffrey (Pvcces)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 02, 2005 - 10:16 pm: | |
Kingfisher, it's real easy IF you can get under your coach safely to test or replace the check valve on the inlet to any leveling valve. Runup blocks or a pit are the only good ways to do this at home that I know of.
The key is to have plenty of room under the coach AFTER it is all the way down on its bottoming rubbers before you undo any connection to the leveling valve.
With the check valve out, there will be no air pressure left in the auxiliary tank. If the minimum pressure valve is holding and the brake system does not leak, there could still be about 65 psi of air in the main tank.
The way to check this is to let the coach settle down (your pressure gauge ought to show zero) and step on your treadle valve. If you hear the air brakes operate, they will be working off of that 65 psi.
If there is leakage in the brake system, it will pull air out of both sides of the system, main and auxiliary, right down to zero.
Good luck troubleshooting your leakage.
Tom Caffrey PD4106-2576
Suncatcher |
mel 4104
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 02, 2005 - 10:31 pm: | |
the best way that i have found to find air leaks is to sectioize the problem. first i made up a air line with a shop air fitting on the end then a peice of air line then a shut off valve then more air line to a 'T' fitting with an air gauge on one outlet and another piece of air line connected to what ever fitting i an taking apart at the time. this test unit will allow you to air up different parts of the system that you want to test using your shop air and not haveing to start the bus. now just hook it up to the line you want to test, open the shut off valve and fill with air then shut off the valve and check the air presure reading and go do some thing else for a while, then come back and check the air gauge to see if the preasure is the same as you left it , if not the get out the soapy water or windex spray bottle and start spraying and watch for bubbles. if you loose the air preasure real quick them you may be able to hear the air leak. if you want you can sectionize it down more just rember there may be more that one place where you have air leaking. a little trick that a bus body man showed me was the use of copper based never seize on the joints, never teflon tape and it sure works as it allows for a better connection. |