Do air suspension valve block have internal leaks..?

[Conor]

OK OK hear me out. This might sound like a bizarre question.

I have a friends 2012 Audi A8 with full air suspension. I changed the two front struts but it still sags on the front right after a few days.

This was a symptom on day 1 .. but then deteriorated to straight up blown air bag. Replacement struts fixed obvious errors but still have the slow leak.

Rhe system is similar to merc in that its ECU, valve block, pump and lines etc.

I put my ultrasonic detector around the strut and valve body but couldn't find a leak.

Only two options now are the line is chafed somewhere or the valve block has an internal leak, is that possible.

Only reason I ask is that my lift is busy and won't be able to trace the air line on the ground.. is it worth changing the valve block? I hate parts cannon.. so just wondering if they ever leak internally.

Cheers

 

[Conor]

OK OK hear me out. This might sound like a bizarre question.

I have a friends 2012 Audi A8 with full air suspension. I changed the two front struts but it still sags on the front right after a few days.

This was a symptom on day 1 .. but then deteriorated to straight up blown air bag. Replacement struts fixed obvious errors but still have the slow leak.

Rhe system is similar to merc in that its ECU, valve block, pump and lines etc.

I put my ultrasonic detector around the strut and valve body but couldn't find a leak.

Only two options now are the line is chafed somewhere or the valve block has an internal leak, is that possible.

Only reason I ask is that my lift is busy and won't be able to trace the air line on the ground.. is it worth changing the valve block? I hate parts cannon.. so just wondering if they ever leak internally.

Cheers

 

[Wearsafoxhat]

As far as I know , they corrode inside if moisture has got into the system. There are “bags” inside the compressor to keep the air dry. That would lead to a poor seal on the valve.

 

[Snake Charmer]

As far as I know , they corrode inside if moisture has got into the system. There are “bags” inside the compressor to keep the air dry. That would lead to a poor seal on the valve.

Yes, most compressors contain a dessicant drier to remove moisture and are an oil free design.

 

[Conor]

Thanks guys.

It's curious alright. I don't know if the failure is at the compressor... because if it was wouldn't the leak be more general across the system/corners...?

Currently, it's just the front right corner that leaks down.. so it's at least at the valve block or else the pipe between valve block and strut. New strut and the plumbing there isn't leaking.

I was just wondering if its possible the valve block could be leaking internally ? I.e. not detectable from outside.. but maybe one of the valve (FR in this case) is leaking back to the pump area or somewhere else..

 

[LostKiwi]

Start with the cheap stuff first.
Disconnect the airline to the FR strut, seal one end then suck to see if it will maintain vacuum. Ideally you want to apply pressure but that requires special kit. Anyone can suck.

 

[alexanderfoti]

Yes, I replace lots of mb valve blocks for internal leaks, sometimes they cause dropping, sometime stop the car going up.

 

[Conor]

Yes, I replace lots of mb valve blocks for internal leaks, sometimes they cause dropping, sometime stop the car going up.

OK cool. What I'm going to do is test out the line going from block to strut for a leak via chafing or such.

After that I'll order up a block.