Compressor Update....

[Iver]

Ok, I checked my dash air gauge and after sitting for two days the gauge had dropped from 115 to 55 lbs.
I started the engine (rpm @ 1000) and the gauge went from 55 to 115 and the dryer purged in just over 3 minutes.
The time between 60 and 90 was around 1.5 minutes.

I shut down the engine and monitored the gauge and after 8 hours it was down to 55 lbs.   Obviously I have leaks to fix but they must be small ones.

We were supposed to take the bus out last weekend so I drove it out to fuel up, drove home, no problem and shut it down. But when I went to move it up to the house to load up it wouldn't air up.

So, I don't understand why the compressor failed to air up the bus that one time.  Zero air regardless of engine rpm.  The book says the compressor can have a sticky valve.  It says the dryer exhaust can leak as well. It's just not happening now......

I have no history on the age of the compressor or the last rebuild of the air dryer.  I can't think of anything more important than a good reliable air system so unless anyone has any ideas, I am considering replacing the compressor and rebuilding the dryer.
          Frustrating.....  Iver.

[lostagain]

Look at the governor first. It may be stuck.

JC

[gumpy]

I agree with JC.  Take the governor off and rebuild it first, or replace it. They're about $20.

I've had my governor stick and not allow the bus to air up, though it was airing up to about 60 lbs, and then blowing off the purge valve on the dryer which would drop the pressure to 35 and start the process over. I smacked it with a screwdriver handle, and it unstuck and started working. It was cold outside when this happened. I rebuilt it, and it's been working fine
for about 5 years now.

craig

[luvrbus]

Iver, I have a AD-2 dryer on my bus and when the dryer needs service it will act the same way if you disconnect the governor line for a moment and it kicks in the air dryer need to be serviced

[Iver]

Actually the same day I had the failure, I went out to an all night truck parts place and picked up a new governor.  After I installed it I ran the engine and the air pressure built up but very very slowly and then finally the dryer purged.

This is why I thought it was the fault of the compressor or the dryer.   As I said the compressor seems to be working now but I just don't feel comfortable knowing it might fail again.

Luvrbus....If as you say your dryer caused a problem with the compressor, maybe I will start by getting a rebuild kit for the dryer first.
         Thanks for all the ideas,   Iver.

[Blacksheep]

If you decide to rebuild your own air dryer, be very careful! Its not a job for the inexperienced! The diesel/bus mechanic that did mine was very cautious and said there were some very strong spring/s inside and the possibility of it blowing apart in your face could happen!

Acr

[gumpy]

If you decide to rebuild your own air dryer, be very careful! Its not a job for the inexperienced! The diesel/bus mechanic that did mine was very cautious and said there were some very strong spring/s inside and the possibility of it blowing apart in your face could happen!

Acr

Well I don't know what the hell happened to this post. I'm not in the habit of writing empty posts.....

What I said in the original was in response to Ace's warning. Basically, I said his dryer must be very different than mine, because I serviced mine, and it was just a matter of unscrewing the old cartridge, and screwing in a new one. No big deal. Nothing blew up on me.

[makemineatwostroke]

Iver; don't let let these guys tell you not to rebuild it yourself there is not a thing that will harm you, the spring on the desiccant cartridge will decompress as you remove the nut from the sealing plate.Buy you xchange cartridge for 50 bucks and screw it in,  has the plate, bolt and o ring same with the valve if it is bad     have a great day

[Sojourner]

Iver....good that you had a new governor installed. All the above report (except the leak down) indicates that either compressor or AD-2 dryer. Whenever it start running your engine and it read zero air pressure next time, see or hear if air coming out of AD-2 purge exhaust. If it is....removing the governor pressure line from AD-2 (near the purge valve) and see if it stop leaking and start pumping. If no change, repair AD-2 purge valve...otherwise to see or feel for air coming out at the ping or muffler tank drain valve in open mode and air coming out of purge valve. If no air and with new or rebuild governor already installed....it sound like the compressor's unloaded valve is stick in unload mode. That calls for compressor replacement or rebuild. All this about compressor unloader valve sticking can be an on & off trouble....sometime it pump and other time no pumping.
Or follow the page 9 and 11,,,     http://www.todaystrucking.com/images/BendixCompressor%20TroubleshootBW1971.pdf

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Leak down is another story. After your air supply is work welling, than you can check for leaks. Tap in discharge line via ping tank with shop air of no more than 120 psi.

Even after all pin points leaks are fix......and still wondering why the air gauge still read lower the next day is because one of two things is happing. The first one is warmed pump air will cool down later to cause the pressure drop a few pound. The second one is the automatic air leveler still need the air supply from tank or optional electric compressor to maintain it adjusted level. Why? Because the coach is floating on air. Every time the coach is senses movement while stand still or traveling, it will either exhaust or add air to maintain that adjusted leveling valve linkage. In other words, every time while standing still and whenever the wind is blowing onto coach or getting in & out of coach or walking around inside of coach will cause the needs of air pressure to maintain it adjusted height.

So every time someone here on the posts, tell about how long it hold air...it all depend on which of the factors of the above paragraph and how big your bus's air reserve tank if it park and no air pumping. So the "How long it holds air?" quotes mean nothing to the bus nut.

BTW....the only way to locking air pressure in air bag such as tires do is to added a 3 points leveling system to by pass automatic levelers. Remember air temperature will control air pressure variable....just the tires pressure change from cold to warm to hot.

Our bus nut Pete/RTS Daytona (retired IBM System Engineer) has a system available http://good-times.webshots.com/album/559324954HVWVXC

Or you can make your own system.

FWIW

Sojourn for Christ, Gerald

[Iver]

Thanks everyone,

     I read in my book about rebuilding the air dryer.  It seems fairly simple and they didn't give any warnings about any dangers.   Hope 2Stroke is right.
     Without having a continuous problem it is difficult to diagnose so the dryer seems like the least expensive way to go to start.  The book says rebuild depending on usage every 1 to 3 years.
     As Gerald says I may have a problem with the unloader valves.
I spoke to a bus mechanic today and he mentioned the valves under the intake plate sometimes stick.  They sometimes spray them with wd40 to loosen them up.
     He also asked where I was getting the intake air for the compressor.  My coach takes air from the engine air intake between the filter and the turbo.  He said to install a separate air cleaner for the compressor intake because the turbo can use up most of the air leaving little for the compressor. Apparently they do that to all the buses in their fleet.  He also says the intake valves can be repaired or a new kit installed without removing the compressor. He explained how to remove and replace them.
      Thanks as always,,,, Iver.
   
     

     

[jjrbus]

Is it possible the new governor is defective?   Jim

[Busted Knuckle]

Is it possible the new governor is defective?   Jim

YES! We had that same exact experience recently on a trip to FL! Had W.W. Williams come out and put a new governor on in Atlanta and by the time it got to Orlando it was not working again! Put a new one on in Orlando and ain't had no mo problems for 3 months! FWIW!
  BK 

[makemineatwostroke]

I like the intake separate too Iver Haldex makes different types of air cleaners for the compressors that can be purchased at NAPA stores when rebuilding the dryer always check and be sure it has a oil filter in the bottom people leave it out and the trash enters into the purge valve piston and the purge valve.Use a remote mount is possible makes for easier service and you already have part of it now on the compressor.   have a great day

[jjrbus]

Is it possible the new governor is defective?   Jim

YES! We had that same exact experience recently on a trip to FL! Had W.W. Williams come out and put a new governor on in Atlanta and by the time it got to Orlando it was not working again! Put a new one on in Orlando and ain't had no mo problems for 3 months! FWIW!
  BK 

  The amount of new items I purchase that are defective is getting greater every year! It is even worse, when I am trying to troubleshoot something. Since Nov of last year I have had 2 new start battries replaced under warrenty, I just bought a new multimeter, one of the test lead sockets was bad. The list goes on, It cant just be me.   Jim

[gumpy]

  The amount of new items I purchase that are defective is getting greater every year! It is even worse, when I am trying to troubleshoot something. Since Nov of last year I have had 2 new start battries replaced under warrenty, I just bought a new multimeter, one of the test lead sockets was bad. The list goes on, It cant just be me.   Jim

It's not you. Most of this crap is made in China.

I purchased some compression fittings to hook up the fuel on my generator. Not one of them would seal. Purchased a different brand from NAPA and they worked just fine. Took the others back and got my money back.

Then, I bought some LED rope light on sale to play with. Initially, it wouldn't even light up right out of the box. Turned the plug around and then it lit, but one section had a short in it. Took it back and got my money back. Didn't buy a replacement.