Don't just ASSUME there's a leak coming from a certain point. Leak test & dead-head your compressor to make sure. IF it's the burst disc replacement is usually very easy. Should be one nut holding it in place (but I'm not familiar with GX).
Good call! GX3 has the burst disk in the hose swivel as in the photo below. The CS2, IIRC, is under the air block which has the pressure gauge and Foster coupler:


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