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 on: Today at 01:32:53 PM 
Started by lvmci - Last post by J_E
A couple of thoughts:

Have you verified that your radiators are clean? both inside and outside?  A build up of dirt, bugs, road debris and other junk between the fins and around the cores will affect the airflow and reduce the efficiency of a radiator.  A simple washing off with a garden hose will not be sufficient to remove something that may have been 'cooked/baked' on over time. 

Look beyond just the radiators.  The coolant system is more than just one or two components.  A build up of scale or other deposits inside the coolant system could keep your radiators from working or even having a chance of working. 

The height of the coolant system above the engine should have a negligible effect on the operation and operational load on the coolant pump. 

If you are going to re-core or replace radiators, I would recommend trying one of the coolant system flush and descaling products and ensure that the coolant system is building the correct pressure.  The potential out of pocket costs isn't that much, the potential savings if you end up not having to pay for a new or re-cored radiator are pretty high.  Plus, if you end up having the radiator work done anyways, you have the added benefit that you've cleaned out some or all of the scale buildup in the block without washing it all into your new or newly re-cored radiator.

 on: Today at 01:11:22 PM 
Started by RickB - Last post by luvrbus
Must because of the vacation in the Rockies with a 8v71 N/A  Roll Eyes,it is silly to hang on to a bus if you don't have time to use it 

 on: Today at 01:03:39 PM 
Started by bevans6 - Last post by bevans6
I wrote a thing but it didn't post.  So...

The typical MCI of that era has the wet tank on the rear wall of the front axle bay, driver's side.  The air dryer is opposite, on the front wall.  The emergency tank is beside the wet tank, passenger side, and has the E-filter and the PPV mounted on it.  The accessory tank is under the driver's seat.  The dry tank is (on my bus) behind the rear wall, driver's side, rear luggage bay.  You open a little trap door to get to its drain valve.  The ping tank is on the front wall of the engine side compartment, passenger side, and has the "drain daily" sticker.  For a full tilt, doing your practical test, don't want to fail because the inspector is fuss-budget stickler for the rules, you need to drain all of the tanks all of the way.  What I do around once a year at the beginning of a long trip, is this:  With the compressor having cut-out and the air dryer purged, I open the drain-daily ping tank AKA the exhaust muffler.  If you open it with pressure it can spray right in your face.  Obviously inspect the output like it's your baby's poop, see what your compressor is putting out.  Next, I drain the wet tank all the way down.  I have cables for the wet and emergency tanks routed to the fuel filler space, behind the door.  Look down. see what comes out.  Go in and look at your air gauge - draining the ping tank and the wet tank should not change the gauge reading much, if at all, proving that the check valve between the wet and dry tank is working.  Next drain the accessory tank.  It should drain down, but the air suspension should not change.  The air gauge should drop to 60 psi, proving that the pressure protection valve (PPV) is working.  It closes with a pressure differential of 60 psi between the accessory system and the service system (the dry tank, mostly) in case of a failure retaining air for a last ditch service brake application.  Next drain your dry tank, on my bus the drain valve is behind a trap door on the rear wall of the driver's side luggage bay.  Now your air pressure gauge should read zero.  Final step is drain your emergency tank.  With everything else empty, drain the emergency tank.  It should sound like it has full 120 psi air pressure when you start to drain it, proving that the check valves that isolate the emergency tank from every other system are working.  This is a reasonably complete test of all of the critical check valves and drain valves of the complete circa 1980 air system, at least on an MCI.  There are other things you can do, one variation tests the shuttle valve and one easy one tests the push pull valve.

The push pull valve operates the parking brake.  It is fed by the emergency tank.  What you can do is chock the bus tires front and rear, do this whole blow-down sequence with the parking brake not applied, and when you finally drain the emergency tank the push pull valve should automatically apply via it's internal spring when the emergency tank gets down to around 25 psi.  There is no pressure gauge on the E tank, so I'm happy if it pops up at some point when air is getting noticeably low.  The shuttle valve is connected to the bottom half of the brake application foot pedal valve, which is fed from the E-tank.  It constantly compares application pressure from the service tank and the E-tank, and if the pressure differential exceeds 45 PSI (I think) it will switch and stop using the service tank to apply all of the brakes and start using the E-tank to apply only the rear brakes via the parking brake port on the DD3 chamber.  This is the beauty of the DD3 - it gives you a number of driver-controlled emergency brake applications from a completely separate air supply if the service brake system has a sudden catastrophic failure.  I worked out a way to test the shuttle valve, but I did it a few years ago and I forget how to test it now.  I think it involves a hill, with the engine off and the whole air system drained, which seems a little dicey to me.

TMI, I guess, sorry.  Brian

 on: Today at 12:53:47 PM 
Started by bevans6 - Last post by Jim Eh.
My understand is that the purge valve remains open all the time between governor cut-out 120 psi) and governor cut-in (90 psi).  It opens when air pressure is applied by the signal line (governor to air dryer) and closes again when air pressure is removed to close the purge valve and activate the compressor unloader valves.  So if the purge valve had stuck, it would have stuck closed, and it was correctly open instead.  It was supposed to exhaust air, and exhaust air it did.  As soon as air pressure dropped to 90 lbs the governor shuttled and activated the compressor and the purge valve closed.  The question is where did the air come from?  Wet tank, dry tank or both?  I expect I will know tomorrow when I get the bus home.


In your first post you said " It obviously leaked and air exhausted out the purge valve until air pressure reached the cut-in pressure, at which point the purge valve was closed by the governor." The valve is not closed by the govenor pre se, but rather it is opened by pressure. Absense of pressure allows the spring to close the valve.

Same as when you said "It opens when air pressure is applied by the signal line (governor to air dryer) and closes again when air pressure is removed to close the purge valve and activate the compressor unloader valves." Again the activation is by spring pressure and ABSENCE of air pressure.

The unloader port is pressurized when the system pressure from the "wet" or supply reservoir tank reaches 120 (or whatever the governor is adjust to) and THEN pressurizes the unloader port which in turn signals the compressor to go into unload stage and at the same time signals the purge valve in the dryer to allow system pressure to flush the desiccant cartridge. The purge valve should remain closed once the flush cycle is complete. Different air dryers accomplish this a little differently. Ones without a "flush reservoir" use system pressure to "back feed" down the line and clean the desiccant cartridge. there are dryers that use a remote tank which the sole purpose is to supply pressure for a purge and is not connected to the main air system.

If you are running an AD9 my guess is, as stated, your purge valve needs servicing. The other possibility is that the line from the "wet" or supply reservoir tank could be partially blocked in such a manner to allow an unloader to work but artificially keeps pressure in the line due to a blockage or a kink that only allows the line to bleed off slowly.

BTW, to test the check valves in the system, start with all air tanks fully charged. Open the drain on the tank closest to the air dryer first, then the next one down the line, and so on. Each time you open the drain that tank should be fully charged as the check valve is supposed to prevent air from traveling upstream to the tank you previously drained.

The pressure gauge(s) should only connected to the primary and secondary tanks (if dual pressure gauges exist) and not to the "wet" or supply reservoir tank.

 on: Today at 11:44:34 AM 
Started by CrabbyMilton - Last post by TomC
When I was a new truck engineer and sales for Los Angeles Freightliner, there were some companies that insisted on MT42 starters. My guess, was they were familiar with it and had spare parts. Otherwise, the MT39 gear reduction is half the weight, takes half the amps and lasts at least twice as long. No down side. Good Luck, TomC

 on: Today at 11:43:36 AM 
Started by bevans6 - Last post by windtrader
Strange? Other words work better for me - "Wonderful" "Amazing" Gift from God" LOL

Fact is there are so few of us CARB gets far better value and ROI harassing others.

 on: Today at 11:39:45 AM 
Started by bevans6 - Last post by TomC
As strict as California is, they require NO annual inspection or NO smog requirement for older buses and motorhomes. Strange...

 on: Today at 11:22:36 AM 
Started by bevans6 - Last post by windtrader

I'm not adding anything to help other than the obvious based on what you posted. That valve is clearly not working properly and letting air out when it shouldn't. I had something similar happening to my tire stem valves. Tires holding air just fine, then I check the pressure and the next day the tire is losing air. The valve was not closing due to some particulates. Fully opening the valves cleared things out and now working fine. Maybe you can really work that valve a few times to ensure nothing is clogging it.

Since wet tank is mentioned here, can you folks confirm the location of them for me. I see there are two tanks between the front tires, each with a valve on the side. I have pulled the ring on both and don't see anything coming out with the air. Is there some other place I am supposed to be clearing the wet tank?  Thanks

 on: Today at 11:11:33 AM 
Started by Scott & Heather - Last post by windtrader
Hi Scott,

I've not been in the details on Eagle pricing but even a ballpark figure is difficult due to many reasons previously mentioned. What makes the range quite wide all come down to the market for this coach and the market is bounded by several factors.

Typically, one assigns a value starting with a coach in running condition so a complete survey can establish an accurate assessment of the operational and functioning systems. Like any non-running auto the value is seriously diminished for the same reason.

One approach is to start with an estimated value assuming the coach is fully functioning then taking deductions based on what is unknown or not working. The other way is to start with a salvage value and add on for what is known.

Since the coach is not running, towing charges affect the number or prospective buyers. It seems like a radius of 500-1000 miles would be generous.

Lastly, the level of effort and time the organization expends marketing the coach influences the final price. There are several auction sites besides eBay but collectively these reach the largest market in the most efficient manner. An interesting strategy might be to list the coach on several auction sites with the same close time. Offers would come in from the most folks at the same time.

Setting a value for your friend - a large range would be prudent to set realistic expectations. Something ranging from salvage value minus some number for tow fees and salvage prep costs to the maximum defined as average market for a similar running coach minus some figure to repair the motor. It seems something like 5k would set reasonable expectation with the folks. A range of 3k to 15k would offer an indication of the wide range of what it might fetch.


 on: Today at 10:50:27 AM 
Started by Billysurf - Last post by bevans6
I've used both and would again without hesitation.  The Castrol lists ash content at 0.8%, while Rotella just says "low ash".  Both are CF2 rated.  If you are in Canada see if Walmart has any straight weight SAE40 engine oil, that's what I normally use and it's dead cheap.


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