| Author | Message | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 178 Registered: 12-2009 Posted From: 69.152.34.29 Rating: N/A |
I'm winterizing the bus today (MC9). Is there anything I need to do do winterize the air system? I've checked the engine coolant and it is good to go for winter. Thanks. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 2193 Registered: 10-2003 Posted From: 71.58.71.157  Rating: N/A |
Drain all air tanks, but leave the drains open, at least overnight. Oil and sludge is very slow in completely draining. Do you have an air Drier? Why not? You could get some air system alcohol and introduce some to the system. (without the air drier.) Some others with alcohol experience (not the drinking kind; although I think some on here use Sterno) can weigh in on the proper way to introduce it. | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 2139 Registered: 12-2000 Posted From: 174.91.145.52  Rating: N/A |
Are you going to drive the coach during the cold weather? If not, drain the air tanks and call it a season. If you are... well, what condition is the air system in? Air drier in good repair? How much moisture do you see, in what time period,in the air tanks? With existing good air system maintenance, no methyl hydrate/brake alcohol will be required, except in arctic conditions. If the air system is wet, then it will trigger crippling disfunction of air valves anywhere in the system, due to the moisture freezing seals and seats shut, preventing the air flowing to where it needs to go. Being aware that Bendix has stopped recommending the use of alcohol in air systems for some number of years now... but that's when the air system has been maintained and is dry inside... Adding alcohol now, and letting it get sucked deep into the system, mixing with whatever moisture is in there, BEFORE it freezes, is the trick. The alcohol is simply an antifreeze, when mixed with the moisture, the freezing point is lowered in the attempt to keep things from getting frozen stuck. Do not introduce alcohol ahead of an air drier. The desiccant will turn to mud, and make blockage in the purge valve, making a big air leak, and possibly crippling the coach. If you have the old alcohol evaporator, great, put it into operation, provided you know for sure there is no air drier downstream. If not, I use a simple outboard motor boat fuel line with priming bulb, with the fuel ends cut off, regular male air fittings and quarter turn valve retrofitted into the drain of the wet tank, female air fitting on outlet end of priming rig. Drain air from wet tank, connect fittings, pump your desired amount of alcohol into wet tank, and then fire up the coach and go for a drive, using ALL air systems, parking brake, service brakes, door locks, wipers and washers, air seat, air horn, and whatever else you have. I might pump half a quart/litre into the coach, as it isn't typically seeing a daily duty cycle. For reference, in the arctic, I'd pump two quarts/litres into a working tractor trailer's wet tank that was equipped with an air drier and check back in 2-3 weeks and see what's left. As you might expect, the relay valves and the foot valve get the lube rinsed out of them pretty good under those type of extreme conditions. Cracking the lines and using a good quality spray lube, not spray solvent(WD40 is bad for this) helps with the psychology in the spring. Once you are dosed, leave the wet tank alone, except if you are using the coach enough that you figure your antifreeze ratio is getting weak, or has been sucked up by the air that has gone through it, then drain and start again. Measure what comes out so you can do some figuring... Not so much a science, more of a feel your way along. happy coaching! buswarrior | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 179 Registered: 12-2009 Posted From: 69.152.34.29 Rating: N/A |
Thank you to all who responded. I do hope to use the coach occasionally this winter. The air system is in good repair and very little oil/moisture drains out of the tanks. The air dryer system was inspected this summer and found to be in good repair. Dessicant was also checked. From the advice, it sounds like I can drain the tanks and be OK. | ||
| Brian Evans (Bevans6)
Registered Member Username: Bevans6 Post Number: 98 Registered: 5-2009 Posted From: 65.92.54.58 Rating: N/A |
Your MC-9 probably has an electrically heated purge valve on the air dryer, if it is still relatively stock. That heater operates when the OTR heater is turned on. If you don't have the OTR heater still in place, it might be disconnected. You could usefully check out the heater and that it is energized either with the OTR heater or with it's own switch. Other tip is if you are driving when it's cold out, always fan the brakes and get the compressor on a charge cycle before you shut down. That way if the purge valve freezes at least it freezes shut, not open... | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 180 Registered: 12-2009 Posted From: 69.152.34.29 Rating: N/A |
Thanks for that tip. The OTR Heat and A/C is all gone. I'll check the wiring schematics for that heater. BTW, on my MC 9 - where is the air dryer? | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 2142 Registered: 12-2000 Posted From: 174.91.145.52 Rating: N/A |
Air drier should be found up in the front axle cavity, fairly centred. Good catch for Brian about the purge valve heater.I forgot to mention it. Air drier purge valve heater is critical for proper function in below freezing temps. happy coaching! buswarrior | ||
| Kevin Baxter (Bus_boy)
Registered Member Username: Bus_boy Post Number: 36 Registered: 10-2009 Posted From: 173.55.131.34  Rating: N/A |
Sterno?! Ha! Good One, John!!! Kevin |