Hello, to be honest I wouldn't get a new pump just for that piece....if it was that important then surely they would have made it more secure to start with. Just like the bigger valve you just opened. Other members on here and other forums have driven their cars for many K miles without it and had no issues whatsoever. I can just imagine how many more owners have had that valve fall out without their knowledge and will never know until they pull the pump...yet their car is running fine.

I'm putting mine back only to see how it sits but I won't leave it there if I feel it will pop out again...and to basically finalize on this issue (other owners will need to know).

Your input and dissection of the pump has been priceless, hopefully others will be able to use it and maybe add more valuable info in the future.

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BMW X5 E53, 4.8iS - 2005
Professional Stereo/Nav with DSP (modified BM54 module) - Converted to Eonon GA5166X with Reverse cam
4-Corner Air Suspension - Converted to BC Coilovers