halocline
Contributor
Likewise mine (I have 5 or 6 Mk10s), although finding parts for them has been difficult for the shop I service them at.
I'm pretty abusive with my gear, don't rinse them after use in salt water, etc.
This is the one thing that will almost certainly destroy a MK10. There is no fix for excessive corrosion in the ambient chamber, which is exactly what happens when you allow salt water to dry on the reg without rinsing.
I suggest you find an excellent repair tech like DA Aquamaster, send him your two best MK10s, and have him pack the ambient chamber with grease. It's really best if you have the model that accepts a SPEC boot. I'll try to post a photo of one of mine later today.
If done correctly, the packed ambient chamber will eliminate salt water intrusion into the ambient chamber and keep your MK10 in much better shape. If you're not using nitrox, consider using silicone rather than PTFE grease for the packing; it's thicker and I suspect longer lasting.