Air system question.......(I'm stumped)

luvrbus · September 05, 2015, 01:00:44 PM

Everything is there in way of plumbing,it probably doesn't have filter looks like the intake hose is headed for the blower which is a common place for the compressor intake on the older buses

Chaz · September 05, 2015, 03:15:40 PM

Cool. I was hoping it was correct. It's how I got it. And it does go above the blower for air.
So how could I clean the system? I'm hoping a good cleaning will help with air up time. I don't know what else could be wrong?

luvrbus · September 05, 2015, 03:36:18 PM

IMO you just have a ton of small leaks most of the time when the tanks are full of curd they air up faster less volume to fill

Chaz · September 05, 2015, 03:42:26 PM

But I "think" the lines may be plugged. I did have to "rod out" a valve (to atmosphere) with a wire to open it up. So I am wondering if that could be an issue.
There also seems to bee a....for lack of a better word.....wispy leak that has a rhythm to it. Hard to explain but - psst...psst...psst...psst...etc. when the motor is running. It is about 1 second intervals or quicker. I just can't find it to tell what it is. I guess it could also be exhaust or something else?

Man, I'm just frustrated with this............
Thanx Luvr.

jackhanow · September 05, 2015, 06:15:26 PM

if the air lines are plugged then the regulator would keep exhausting, ie unloading the compressor. i have an old mc5 that unloads into the intake so you dont hear it blow off. only can tell when the sound of the motor changes.

Scott & Heather · September 05, 2015, 09:16:01 PM

I love the sound of blow off! Sets the bus apart from all the coal roller pickup trucks out there. Can someone answer his question about what to use and where to insert cleaner for the lines? I'm curious tok

Sent from my iPhone using Tapatalk

luvrbus · September 06, 2015, 05:31:25 AM

I never heard of injecting a cleaning agent into a Bendix system, the main supply line will coke up and you just change it.
Bendix tells you it will take a while with draining the the tanks to clean the system after a compressor failure adding a cleaning agent they make no mention of it

You can probably buy some type snake oil that will tell you how great and easy it is,I wouldn't attempt it to many sensitive valves,o-rings,diaphragms and seals to chance it IMO

jackhanow · September 06, 2015, 07:01:33 AM

I know when you do get oil in the air system it's usually black and thick like gear lube. Any way the oil accumulates at the bottom of every thing and will come out when you drain the water out. May be a separator on the right wall of the engine compartment. Should have a drain on it be careful because the goo will come shooting out of it. And the oil come out best under pressure because it's so thick.

Jim Eh. · September 06, 2015, 07:48:00 AM

IF you wanted to go through the effort you could use methyl hydrate to flush the lines (disconnect both ends). If any valves need cleaning best to remove, disassemble, clean and reassemble with a rebuild kit.

eagle19952 · September 06, 2015, 09:21:13 AM

Quote from: krank on September 06, 2015, 07:48:00 AM
IF you wanted to go through the effort you could use methyl hydrate to flush the lines (disconnect both ends). If any valves need cleaning best to remove, disassemble, clean and reassemble with a rebuild kit.

I have and have seen 100's of rigs in the Arctic that had HEET poured and pumped thru the air systems. none suffered any damage.

Mostly to facilitate freezing, but it does move sludge, to a point. it may not cure..but it won't hurt.

i would definitely inspect the main discharge line.

jackhanow · September 06, 2015, 10:15:09 AM

The oil is only suspended while the air is compressed as the system cools off the oil condenses and reliquifies. The heat from compressing the air turns the oil into a vapor that can be explosive, but would need an ignition source. Adding any flammable solvent would oh lower the flash point of the gases in the system. Best is just disconnect the lines and blow them out as best as possible. The tanks are not bothered by the oil. Just keep draining them. Once in the bottom of the tank. The oil stays liquid. But may cause the bottom of the tanks to rust more if you leave the water in them. In a fuel system the low oxygen levels keep the electric fuel pump from ignighting the vapor. in compressed air system the oxygen level could produce the right level of carburetion. And you shouldn't be adding any vapor if you replaced the compressor with a good reman.

Lin · September 06, 2015, 10:33:00 AM

When i first got this bus, there was a problem airing up according to the dash gauge. I decided to change the sensor. When I took off the old one there was a large amount of slop that began to ooze out. It seemed to me that the location of the sensor, below the driver in the spare tire compartment, put it at about the lowest and most distant point from the compressor. I think Luke had said that I could try running some alcohol through the system to clean it, but I never did. I just drained what I could and put the new sensor on. No problems since, but sometimes I think I should open it up and see if there is anything more there. I would guess that if one were to remove the sensor and start up the bus, it would blow a lot of crap out.

eagle19952 · September 06, 2015, 01:34:33 PM

Quote from: jackhanow on September 06, 2015, 10:15:09 AM
The oil is only suspended while the air is compressed as the system cools off the oil condenses and reliquifies. The heat from compressing the air turns the oil into a vapor that can be explosive, but would need an ignition source. Adding any flammable solvent would oh lower the flash point of the gases in the system. Best is just disconnect the lines and blow them out as best as possible. The tanks are not bothered by the oil. Just keep draining them. Once in the bottom of the tank. The oil stays liquid. But may cause the bottom of the tanks to rust more if you leave the water in them. In a fuel system the low oxygen levels keep the electric fuel pump from ignighting the vapor. in compressed air system the oxygen level could produce the right level of carburetion. And you shouldn't be adding any vapor if you replaced the compressor with a good reman.

seriously ?.... back before air dryers, every vehicle that encountered freezing and potential frozen condensate in an air system had an alcohol evap system... haven't heard of any railroad cars exploding....

jackhanow · September 06, 2015, 02:41:42 PM

The difference is the alcohol is misted in after the compressor not though the compressor and there is no ignition source besides the fact it's a really small amount of alcohol unless your trying to thaw the system because you didn't fill the jar soon enough. And every time you pump the brake the vapor passes to the outside. Simple science is compression makes
Heat and expansion cools.

chessie4905 · September 06, 2015, 03:05:29 PM

Get a mechanics stethoscope and start hunting near compressor. Also drain all air tanks and leave drains open to allow accumulated oil and sludge to completely drain out, at least one or two days. Tank at rear bulkhead, in compartment under driver, and two above batteries on 4905. My 4905 has air drain pushbutton inside fuel filler door for the main air tanks. Make sure all drains actually work and aren't plugged up. The air system is designed to accumulate most of oil and moisture in wet tank; much less in others that receive their air from wet tank. An air supply to the system without engine running can be very helpful.