Mb Telescopic Piston Issue

December 2, 2018

My 146s telescopic piston is acting up. It will extend just fine, but it not retract. The threads slip (thats what it feels like). The piston will retract 2mm or so and slip. I ensured the cork has silicone on it, etc. Still doesnt work.

Advice please

December 2, 2018

Sia,

You need to "back-up" the piston against the section to rearm the slipping clutch which sits inside in the filling knob.

See the section drawing of the system of the Montblanc 14X and 13X below .

Click on the picture to see it in larger format

Best regards,

Francis

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December 3, 2018

Thanks for the excellent pictures, Francis! I do back up the piston against the section. This used to work just fine, its started misbehaving suddenly. I pulled the pen out after months of storage. I dont know what might have happened. Is it possible the cork is too tight? Though it doesnt really seem like that but maybe I should make the cork a looser fit in the barrel?

Edited December 3, 2018 by siamackz

December 3, 2018

Thanks for the excellent pictures, Francis! I do back up the piston against the section. This used to work just fine, its started misbehaving suddenly. I pulled the pen out after months of storage. I dont know what might have happened. Is it possible the cork is too tight? Though it doesnt really seem like that but maybe I should make the cork a looser fit in the barrel?

Does the piston makes its full in and out stroke when not mounted in the barrel?

If this is the case the radial pretension of the cork - cork diameter ideally 0.15mm larger as the barrel bore - might be too high….

Could be the female secondary (large) lead screw thread is nearly stripped. in this case the lead screw gets easily blocked and the slipping clutch slips.

Francis

December 3, 2018

Yes I does extend and retract without the cork. I think youre right, the threads are nearly stripped and too much cork tension causes slipping. Ill make a new smaller cork and try and report back