Rear height corrector vent tube

[michaelr]

Here is the problem:
When I got my BX it was leaking from the rear height corrector. When I got under and looked I found the dust cover and the diaphragm retaining ring were missing. Easy fix, I had spare rubber bits that also fit my DS!

A couple of weeks later it was leaking again... split diaphragm so replaced again.

And again! Dust cover gone, diaphragm split! The only thing I can suspect it that the plastic vent pipe is blocked and leak-by fluid is blowing things apart.

I can find no place where the plastic pipe is pinched under the sills, where else should I look? Maybe if I know where the vent pipe can be found at the reservoir I could blow a little air back down the pipe? In the mean time I think I will lead the vent pipe into a "catch can" after checking the internal passageways in the corrector for blockage. Any other suggestions?