Replacing Air Compressor
05-26-2011, 05:03 AM
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Replacing Air Compressor
I have replaced all leaking airbags with arnott's gen 1 airbags but my compressor still runs quite frequently even though I am not losing ride height. I am purchasing the Wabco replacement pump from Arnott but cannot find any instructions anywhere on how to replace it. Obviously I would rather do this myself instead of taking it to the dealer. How hard would this be? Is there any guides out there?
05-26-2011, 08:10 AM
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05-27-2011, 04:50 AM
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What tools will I need. I have no access to lifts or anything. What do you do to bleed the air before you remove the existing pump?
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05-27-2011, 09:24 AM
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Although unlikely, it is of course possible the accumulator is leaking air. However, I would be very surprised that a pin hole leak would occur in a thick walled aluminum "balloon" unless the car was in an accident and the accumulator was impacted.
It is more likely there is a leak in an air hose connection. There is an air hose between the pump and the air distribution block, another hose from the distribution block to the accumulator, and a hose to each air spring. That's six plastic hoses in all - 12 compression fittings. If there is leak it would most likely be at the compression fittings, not the aluminum accumulator itself. A hose might leak if it was damaged by abrasion, or kinked or cut.
The compression fittings must not be over-tightened. I cannot imagine the fittings will loosen on their own. So unless someone has been manipulating the compression fittings, there should not be a leak at those joints. It's possible that when the compression fittings were re-installed at the new air springs that the fitting was cross threaded, or the hose was improperly inserted into the fitting, or that a brass ferrule surrounding the hose (inside the compression fitting) was not installed or broken, or the small o-ring in the fitting is damaged or missing.
It is also possible the air compressor has a non-return valve (check valve) which does not close completely. Or the discharge valves (#7 and #9) do not close completely. The discharge valves are activated when the suspension requires lowering. (EDIT: Note that the information from the Solenoid Valve page below mentions that the air pressure within the air springs actually closes the individual air valve solenoids. Thus, without power the valves stay closed. Therefore, I suggest that you can pull the fuse on the air suspension system and wait for a while, watching the individual wheel heights. Yes, using the "jack mode" would do the same thing (prevent the system from automatic leveling) but if the suspension control electronics were at fault you would not know the actual cause.)
But note:
When my Arnott air springs (front only) were installed by an independent repair shop, the mechanic did install the fittings correctly, but did not properly install the large o-rings at the top of the air spring. In fact, he did not use the larger cross section o-ring supplied by Arnott (he re-used the smaller cross section o-rings from the OEM air springs). The improperly installed o-rings slowly leaked air. I had to take everything apart myself and change the o-rings, remove the petroleum based lubricant he used in the o-ring grooves (which will damage the o-ring) AND properly lubricate with a non-petroleum lubricant (I used Krytox 240AC).
It is more likely there is a leak in an air hose connection. There is an air hose between the pump and the air distribution block, another hose from the distribution block to the accumulator, and a hose to each air spring. That's six plastic hoses in all - 12 compression fittings. If there is leak it would most likely be at the compression fittings, not the aluminum accumulator itself. A hose might leak if it was damaged by abrasion, or kinked or cut.
The compression fittings must not be over-tightened. I cannot imagine the fittings will loosen on their own. So unless someone has been manipulating the compression fittings, there should not be a leak at those joints. It's possible that when the compression fittings were re-installed at the new air springs that the fitting was cross threaded, or the hose was improperly inserted into the fitting, or that a brass ferrule surrounding the hose (inside the compression fitting) was not installed or broken, or the small o-ring in the fitting is damaged or missing.
It is also possible the air compressor has a non-return valve (check valve) which does not close completely. Or the discharge valves (#7 and #9) do not close completely. The discharge valves are activated when the suspension requires lowering. (EDIT: Note that the information from the Solenoid Valve page below mentions that the air pressure within the air springs actually closes the individual air valve solenoids. Thus, without power the valves stay closed. Therefore, I suggest that you can pull the fuse on the air suspension system and wait for a while, watching the individual wheel heights. Yes, using the "jack mode" would do the same thing (prevent the system from automatic leveling) but if the suspension control electronics were at fault you would not know the actual cause.)
But note:
When my Arnott air springs (front only) were installed by an independent repair shop, the mechanic did install the fittings correctly, but did not properly install the large o-rings at the top of the air spring. In fact, he did not use the larger cross section o-ring supplied by Arnott (he re-used the smaller cross section o-rings from the OEM air springs). The improperly installed o-rings slowly leaked air. I had to take everything apart myself and change the o-rings, remove the petroleum based lubricant he used in the o-ring grooves (which will damage the o-ring) AND properly lubricate with a non-petroleum lubricant (I used Krytox 240AC).
Last edited by Mr. Timewise; 08-13-2011 at 08:04 AM.
06-02-2011, 05:54 AM
#10
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compressor change-out
You can do it on your back with jackstands, ramps, etc. I'm sure. I did it on a lift so it was easier for me. I didn't bleed anything...just took off the air hose(s) and had at it. Its kinda tricky the way it hangs up in there off the body, you'll see. If you can change spark plugs you can do this ! 8-)
Good input by Mr. Timewise btw...
