There HAS to be a part number for this....




I can not find them (with out the whole solenoid). I find couplers (abourt $80 for MB) but not these on their own. Note: there are two sizes in this image - the solenoid takes one big, two smaller (This is for E for so so many generations).
Thin k it was like $15 for a full coupler (so two compression rings).




Last edited by OldManAndHisCar; Feb 24, 2026 at 11:32 AM.




I'd much rather have a new one but just in case you can't buy it.




brass ring
It seals with a standard dual-cones besides it has a side-cut that has to rely on secondary seal...
How to beef up this coupler for zero leak assured between plastic and brass ... RTV Silicon??
Last edited by CaliBenzDriver; Feb 24, 2026 at 12:51 PM.
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The Best of Mercedes & AMG
McMasterCarr should have something that will work. search tubing. you will need to measure the size on the car.
can't give you exact part#s because I haven't replaced mine yet.




McMasterCarr should have something that will work. search tubing. you will need to measure the size on the car.
can't give you exact part#s because I haven't replaced mine yet.
I have searched so much I am shocked I have not found Bigfoot or Emilia Erhart.




inner profile lip
The 2x right rings are specific for your application - Notice how the inside profile is not smooth. There is a lip that bites in the plastic hose for a tight seal.
That's all good except for the straight split is far from a 100% seal.
straight cut edge... leaks pressure
The two halves get nearly sealed by coming in close contact -That is a guaranteed slow leak right there.
How to seal 100% the ring slot leak...
something has to be in there: silicon grease or RTV ??? (look up "pipe dope" : same principle with silicon)
I don't have a way to experiment using that solution.
At least what is clear is why these connectors leak either a little or a lot. Knowing that, yours don't have to!
Overtightening plastic develop stress cracks: "2 fingers GNT" max!

Last edited by CaliBenzDriver; Feb 24, 2026 at 03:40 PM.





You've searched so much you have found the root cause of this old fashioned AirMatic built-in trouble.
less leaking
less pumping
less condensate
less rusting & freezing
better suspensions control.

Last edited by CaliBenzDriver; Feb 24, 2026 at 02:58 PM.




Looks like a Metric or maybe G (BSPP
What is max pressure in air lines?
Look online for Push to connect air line fittings.
So on one side is the mechanical thread connection and the other is just a place to shove in the airline where the fitting grabs, holds and seals airline.
Used a lot on on & off road trucks - Think Garbage trucks.
SMC makes some as do others.
push-to-connect tube fittings | McMaster-Carr
just figure out that male thread and off you go.





