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Author Topic: Air System Help Please  (Read 2034 times)
travlinman
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« on: November 24, 2011, 07:05:48 PM »

Hey Guys,

After much reading here on the board I am diving in on my first DIY service on my 4106. Things have been going well, I am done with the oil and fuel filters. So today I started on the air dryer service. After a bit of wresting I got the end cover off and what I found was not pretty. There is this oil water mix on the end cover and around the seal. The rest of the dryer has a light film of oil inside and the discharge hose does as well. I have been wondering about my compressor for a while now, when I drain the reservior I get a bit of oil on my fingers. SO, what do you guys think?? I am guessing this is not normal as the air dryer was serviced less than 10,000 miles ago. Thoughts...here are a few pics.

TM
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bevans6
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« Reply #1 on: November 25, 2011, 04:49:41 AM »

You do one of two things when you open up something like that - smile with satisfaction, or grimace with anticipation...  I think you did the latter.  Constant oil in the compressor discharge means a new compressor sooner rather than later.  I changed mine well before there was an issue simply for preventative maintenance (and because my engine was out), and I used a Bendix re-manufactured unit.  It was around $500, give or take.  Lets you inspect the drive gears (maybe change to steel if you have fiber), change the gasket, change the governor, replace the crusty old air hoses to the governor, probably you should replace the big discharge hose too.  Then, you've done what you need to do and can again smile with satisfaction!  Trust me, it's a good feeling!

Brian
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1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
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Joe Camper
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« Reply #2 on: November 25, 2011, 05:39:10 AM »

I would tend to agree with what Brian said and would add that your photos are about normal in terms of what I'm usually looking at when I service one. That lower chamber of the drier is precisely where all that crud should be accumulating and migrating down and out.

The first time I opened mine up the canister with the beads in it was completely empty and I was baffled. I also had mega amounts of the grey matter in the air tanks as well as the bottom chamber of the drier.

I too assumed the grey matter was oil contaminated water but I now wonder if it was what was left of the silicone beads. Since then I see nothing accumulating in the tanks at all and I see that same grey crud in dryers on vehicles way newer on a regular basis.

The newer AD9 with the spin on filters......when I service those that same grey crud exists in its base.

Another thing specific to the AD2. There is a heating element built in the base of that dryer that is not serviceable. Rebuild kits may or may not include a thermostat that many confuse with the heat element but it is not. The heating element itself is embeded in the base and is not serviceable if it goes bad you need a new base and they are getting scarce from what I am told.

To test the heating element put the base in the freezer for a while and then do a continuity test from the wire terminal to the base itself for the ground. If you have continuity the heater is working.

Definatly keep an eye on it and if you begin to drain the tanks and actually see black matter I would be figuring on a new compressor for sure.
« Last Edit: November 25, 2011, 05:52:33 AM by Joe Camper » Logged

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« Reply #3 on: November 25, 2011, 06:18:05 AM »

Be sure and check the air intake source before changing compressors you see some of the 4106 tied to oil bath filters sucking oil from the old oil bath cleaners.

I had one where the owner made himself a heavy duty gasket lol and plugged the return and filled the compressor with oil and it made oil like a oil well was nothing wrong with the compressor

good luck
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travlinman
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« Reply #4 on: November 25, 2011, 07:42:41 AM »

Clifford - My bus has been converted to a paper element, but that is a good story.

Joe - Thanks for the heater tip, I will try that after I clean up the base today.

Brian - Looks like I will be doing a compressor while I have shop access, better now than on the road next summer.

OK, so where is a good source for a Bendix rebuilt compressor?  After reading about Chaz's drama I know where I will not be buying mine!!!!!  There is a Pacific Power near the shop so I think I will start there. Any other recommendations?HuhHuh??

Thanks as always,

TM
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« Reply #5 on: November 25, 2011, 08:28:24 AM »

Another tip.  A lot of us have repowered our older coaches that originally came equipped with the AD-2 dryer.  In the case of repowering to the newer Cummins (and I suspect the S60 and Cat also, but does not apply to the TuFlo series) you will need to install an econ valve after the compressor.  What this does is hold pressure in the compressor after it unloads, and prevents oil from passing by the compressor rings, which winds up in the dryer.  This might trick you into thinking that the compressor is shot.  In my case (Cummins ISM) I simply installed an AD-9 dryer, which has a built in econ valve.  The cost of the econ and shipping was nearly as much as a new AD-9, so no brainer on that.  Problem solved.  Like Clifford says, take your compressor intake air from a good clean non presssurized source. Hope this helps.
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« Reply #6 on: November 25, 2011, 08:35:38 AM »

Steve, from the looks of the rest of your engine I doubt you need a new compressor, those old TuFlo's will go for hundreds of thousands of miles.  But if you do, I get mine rebuilt or exchanged at Brake Systems in Portland.  They will be a lot cheaper than Pac Diesel.  The oil means it's doing it's job, just service it and keep draining the wet tank IMHO.
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travlinman
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« Reply #7 on: November 25, 2011, 10:43:53 AM »

Mark,

Thanks for the info, I have a TU-FLO 600 compressor on my 4106. So from your post I would not need the econ valve? I am learning as I go here so don't be afraid to spell it out for me! Here is a pic of the compressor.

Thanks

Steve
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robertglines1
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« Reply #8 on: November 25, 2011, 11:00:30 AM »

lOOKS like recent install. Sure oil isn't left from past failure and isn't residual left over and just working it's way out of system?  Why I think so is hoses, gasket material and general apearance of compressor. Might ck rebuild tag.   Bob
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« Reply #9 on: November 25, 2011, 12:02:09 PM »

I agree with Bob!  I would, before doing anything else, take the discharge hose off (the air output hose directly connected to the air compressor head), clean it very well, and see if it gets soaked with oil inside.  If it doesn't, then perhaps your air system just has the remains of oil from a previous compressor.  There is a difference between a little oil making the water dirty, and oil...

Brian
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1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
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travlinman
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« Reply #10 on: November 25, 2011, 02:06:25 PM »

OK sweet, I will pull that line and see what I get.

TM
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Steve & Kristen Full time nomads since '06 - PD4106-674  8V71/V730
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« Reply #11 on: November 26, 2011, 07:16:10 PM »

No, does not apply to you Steve, that's only on the Holset compressors with an AD-2 dryer.  I doubt you need compressor work but if you ever do you could go up to the TuFlo 700 or 750.  Just service the dryer, it will clean the system up in time, might take a couple services to make the system bone dry.  You might include a purge valve kit in your project as long as it's apart.  I applaud your efforts in the maintenance area.
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« Reply #12 on: November 27, 2011, 06:43:31 AM »

  Okay color me dumb, but every diesel has really black, black oil. If the compressor was throwing oil into the air system, even mixed with water I would think it would be real dark blackish brown?? So does the color of slop in his drier look normal color, or is it like Joe Camper suggested, the remains of those grey silicone beads?

  A bit off topic, I asked this before but do we really need a drier? My MC5 never had one, just has a Whiskey sniffer. I'll likely never drive in freezing conditions unless something unexpected comes up, like a new grand baby or another funeral.

  It just seems like these driers are just another thing to fail, and theres always threads about drier problems and failures. Long as we blow the tanks a lot we should be okay, right??
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luvrbus
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« Reply #13 on: November 27, 2011, 06:59:24 AM »

Paul, the dryer is to collect the oil from the compressor also they not just for freezing weather 

good luck
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« Reply #14 on: November 27, 2011, 07:34:44 PM »

Yes, I was expecting to see pictures with black ooze from the pits of Hades.

That stuff you've got looks routine to me, but I usually saw these in a transit environment, so my mileage may be biased....

I priced a new AD2 purge valve and desiccant kit, it comes out to the same price as a rebuilt AD9...

I fear my AD2's days are numbered, as the purge valve is shot, and extreme violence is in the cards for removal.

happy coaching!
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« Reply #15 on: November 27, 2011, 10:19:09 PM »

Paul, the dryer is to collect the oil from the compressor also they not just for freezing weather 

good luck

  Yeah I follow that, but if your blowing the tanks down regularly, etc...would it really matter? IOW, I'm looking for someone to convince me that adding a $200 plus air drier plus all the hose connecting and wiring is going to offer me something more than something else to break. Will the brakes chambers or other brake parts last longer?

  My understanding of the drier was its primary purpose was keeping the system dry of water in freezing environments. I will likely have to have a gun pointed at my head to ever drive anywhere below 50*F.
 
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Nineforever
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« Reply #16 on: November 28, 2011, 03:50:02 AM »

Experiences I've had with air dryers are that they are nothing but a pain anything below -25 . Best idea is to crawl under your bus close the valve .The best deffence in winter operations is install a  Sniffer bottle keep that full drain your dry tank regularly . Carry wheel chucks park on the flat < dont use your parking brakes > unless  your shutting down for the night . Brake saver in the sniffer only < straight methol hydrate only in a pinch it will eat rubber orings > carry a full bottle of propane w/ tiger torch   with a piece of stove pipe to warm things up just in case .
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Hyway 3 100 klms south of Yellowknife NWT Canada
Joe Camper
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« Reply #17 on: November 28, 2011, 06:47:47 AM »

I disagree. Up north you need it to keep from freezing the air system down south you need to keep the moisture out.

I would never opporate any air brake vehicle without something on it to address the issue. EVER

They have a service interval of 2 yr possibly all the problems all have is with stuff that has not been serviced correctly.

On my Pete the AD7 was 179 bucks rebuilt with exchange and I never ever had a lick of trouble with them on a 2 yr cycle. Takes an hr or 2 to swap it. IMO not a big price to pay for trouble free service.

You could go with an alcohol snifter for a vehicle with very limited use but that is a bit antiquated and a PITA if you run the bus daily.

Napa has the desiccant canister for the AD2 for like 49 bucks very cheep. Lot easier than re plumbing to fit the different configuration of the newer models.

2nd biggest related failure after lack of suggested service interval and resulting from the same is the heating element. If you are freezing up the exhaust port the heat element has failed.
« Last Edit: November 28, 2011, 07:21:33 AM by Joe Camper » Logged

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« Reply #18 on: November 28, 2011, 08:45:10 AM »

I tend to agree with Joe.  We operated coaches that all had dryers, in a wide temp and climate range; from 0 to 120 deg F and from desert to high humidity and rain.  We never had problems, maybe the occasional purge valve sticking. But we serviced the systems as per manufacturer's specs or sooner.  There's a reason they are standard on heavy vehicles.  Only bus I ever saw without one was a MC-9 we bought from a transit district in LA that only had expello valves on it.
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« Reply #19 on: November 28, 2011, 08:58:09 AM »

Once an exhaust port is froze all additional moisture from that point accumulates in the dryer till it plugs frozen and you can no longer make air pressure.

This is arguably the most common failure up north.
« Last Edit: November 28, 2011, 08:59:56 AM by Joe Camper » Logged

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travlinman
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« Reply #20 on: November 28, 2011, 12:42:34 PM »

Just for a current cost perspective, I spent $48.88 for a rebuilt desiccant cartridge, and the kits for the purge and check valves. Pretty cheap in my book for a healthy air system. If I did not have one of these on my bus I certainly would put one on. Just my 2 cents....

TM
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Steve & Kristen Full time nomads since '06 - PD4106-674  8V71/V730
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« Reply #21 on: November 28, 2011, 02:12:51 PM »

(snip)  If I did not have one of these on my bus I certainly would put one on.

       My bus (1976) was built with a methanol bubbler and an "oil condenser".  This condenser is a canister a bit smaller than a proper air dryer.  It had a pair of wet tanks with a drain valve on each one (both completely rusted away and replaced with a modern spring brake system).  Very high on the "things on the priority list" is installing a proper ari dryer (with a more useful governor instead of the original unloader).  The bubbler is before the compressor so it has to go.
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Nineforever
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« Reply #22 on: November 28, 2011, 07:03:11 PM »

That's just been my experiences with air dryers when it drops below -25 any thing above they worked fine rather then being froze up in the arm pit of know where i close the valve keep the sniffer bottle full maybe Wrong but it works for me  i could pull over on the side of the road at -55 plus the wind chill have a snooze for a few hours jump back into the seat and pull away trailer s and all no wheels dragging. I'm no expert or mechanic just a driver since i was a kid and learned many hard lessons driving truck in extreme conditions found that most of the time what they say in the owners manual just doesn't work up here . Pa car was up here last year with one of there test vechiles , they timed there arrival just right it was minus -50 for a week ...... need i say more I'm sure fellow members from Alaska can appreciate where I'm coming from .
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