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Is my Compressor broken or not???

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Meho1969, Apr 21, 2013.

Page 1 of 3
  1. Apr 21, 2013 #1
    Meho1969

    Meho1969 Light Load Member

    79
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    Nov 6, 2012
    St Louis, MO
    0
    Alright so I really need some help to figure this out. I have a 07 Volvo VLN 670 with a Ved D-12 Volvo engine (435 hp). My compressor keeps running and pumping air ALL THE TIME... by all the time I mean that it, keeps building air in the air tanks and the air purge valve, keeps re-purging all the air every about 1 minute. I have spoken to many people, and I have gotten mixed comments. Some people say that my compressor is broken and I need to replace it ( of course that is the costly way to go) and other people again (most of them own Volvo's) say that it is not gone. A lot of people say that if the compressor breaks or is broken, it will not pump and build air up at all, but mine does all the time. I have changed the air governor (twice), I have changed the air filter, and I have checked all the lines that lead up to the air dryer. There are NO AIR LEAKS on the truck what so ever. The only other thing that I am thinking is that when I had my firewall changed ( the tablet with all the air lines under the hood, with all the air wires) that maybe there the tech that did it, did not connect the lines right. I was told by one guy who also has the a Volvo that maybe I need to switch out the positions of the blue air lines that go into the governor.... I am really puzzled on this one and would appreciate and love to see some other opinions about what I could possibly do, before I go ahead and break the bank to replace the compressor.
     
    Meho1969, Apr 21, 2013
    Meho1969, Apr 21, 2013
    #1
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  3. Apr 21, 2013 #2
    Heavyd

    Heavyd Road Train Member

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    If your dryer is purging all the time this usually means there is a big air leak somewhere in either the unloader line between the governor and air compressor/ unloaders themselves in the air compressor or the signal line to the air dryer. The unloaders inside the air compressor are the usual culprit as this is where all the heat and carbon is and that wears out the seals. No sure about the compressor on your truck, but most manufacturers haves some relatively easy way to service the unloaders.
     
    Heavyd, Apr 21, 2013
    Heavyd, Apr 21, 2013
    #2
  4. Apr 21, 2013 #3
    Les2

    Les2 Road Train Member

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    Governor? Air dryer?

    Personally if go the governor route.
     
    Les2, Apr 21, 2013
    Les2, Apr 21, 2013
    #3
  5. Apr 21, 2013 #4
    Heavyd

    Heavyd Road Train Member

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    He already changed the governor, twice. Do you think it needs a third one?
     
    Heavyd, Apr 21, 2013
    Heavyd, Apr 21, 2013
    #4
    cetanediesel Thanks this.
  7. Apr 21, 2013 #5
    GrapeApe

    GrapeApe Road Train Member

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    Jan 7, 2013
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    It could be several things, compressor unloader, air leak in the purge/unloader line from the governor, the purge valve in the dryer.

    I check them with the engine off and rubber tipped blow gun. Pull the unloader line off the goverernor and blow in it. The dryer should purge. then have no leaks. Then you can blow into the unloader port on the compressor to check for leaks there,
     
    GrapeApe, Apr 21, 2013
    GrapeApe, Apr 21, 2013
    #5
    Meho1969 Thanks this.
  8. Apr 21, 2013 #6
    Les2

    Les2 Road Train Member

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    kicked back in my lazyboy...
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    I missed that in the rambling of his post...LOL.

    Maybe try resetting the pressure on it? Turn it down a little and see if it continues to do it.

    His problem sure isn't the air compressor, its something else, probably something stupid!
     
    Les2, Apr 21, 2013
    Les2, Apr 21, 2013
    #6
  9. Apr 21, 2013 #7
    Meho1969

    Meho1969 Light Load Member

    79
    4
    Nov 6, 2012
    St Louis, MO
    0
    I will have to check that out too, but with my luck Volvo does not have a easy fix for this, I have a Volvo Compressor dual pistons, or as they say dual lungs....
     
    Meho1969, Apr 21, 2013
    Meho1969, Apr 21, 2013
    #7
  10. Apr 21, 2013 #8
    Yogibear

    Yogibear Light Load Member

    64
    24
    Nov 4, 2008
    Bristol, Florida
    0
    It is most likely the unloader in top of the compressor. depending on what brand it is there are usally 2 screws holding down a retainer plate, under there will be the unloader. The cat engines run pretty hot and cause unloader problems. the good thing is it is only about a $75.00 fix if you do it your self. If you decide to do it yourself be sure before you reinstall the new unloader that you clean the bore it sits in. It will look like a oven that hasnt been cleaned in a while, and oven cleaner works wornders cleaning it. Be sure you dont leave any reidue as the cleaner is rough on the new orings.
     
    Yogibear, Apr 21, 2013
    Yogibear, Apr 21, 2013
    #8
    Meho1969 Thanks this.
  11. Apr 21, 2013 #9
    Meho1969

    Meho1969 Light Load Member

    79
    4
    Nov 6, 2012
    St Louis, MO
    0
    Well I have changed two of them already, now the only other thing that I am thinking maybe is to go ahead and change the air lines ins and outs on the governor, because there are two blue air lines and I have had many guys tell me that switching the two blue lines positions out, might make it stop purging all the #### time.
     
    Meho1969, Apr 21, 2013
    Meho1969, Apr 21, 2013
    #9
  12. Apr 21, 2013 #10
    Meho1969

    Meho1969 Light Load Member

    79
    4
    Nov 6, 2012
    St Louis, MO
    0
    Well the only bad thing is my unloader valves are I think inside the #### compressor, and with a volvo compressor it seems to be really hard to get to them since they are in the head of the compressor, I will do some research and see what I can come up with
     
    Meho1969, Apr 21, 2013
    Meho1969, Apr 21, 2013
    #10
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