Miehle V50X update

Well I spent half of my Saturday trying to get my vacuum pump running on my V50X. I do not have a problem with the carbon vanes they are the correct width and slide easily. The problem I am having is…..After reassembly the pump binds at the top I cannot seam to get away from this after tightening down all the bolts holding the covers. I do it little by little and all is fine until I tighten the bolts completely. I think the problem now is the bearings out of true with the shaft. Any suggestions???????

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It’s the length of the vanes, not the width. You cannot compress them by tightening the end bolts, thus they need to be made flush with the end of the rotor. They are deliberately made a trifle longer to get a snug fit after truing up the length for your particular rotor.


If the pump was working up to the point it was dismantled, albeit badly, is it as simple, in your efforts to refurbish you have inadvertantly introduced some crap between the blind end of the rotor and the back of the body, where the shaft goes through the body & the bearings, the crap that builds up on the rotor between the *lands* of the rotor invariably semi-cooks into evil little hard lumps, not easily compressed to waste???. . With a 6” inch engineers rule simple test across the end face of the rotor and the periphery of the casing, sight and light test should be/has to be perfect otherwise No seal!!! . Especially if it is proud by even 1/2 a thou.!!!
If you suspect or prove that some aforementioned crap is present with a 50/50 mix of ordinary lube oil and liquid metal polish (as used by the butler on the family silver?) squirt a few shots into the pump rotor, turn by hand, via the main flywheel, (MOTOR OFF of COURSE) and see what dribbles out, the secret mix will break up any foreign body(s) but will not hurt the internals, obviously washed out with (you say kerosene) but any evaporating spirit.!!
And even, the rotor with, new vanes, LUBED UP, prior to re-assembly with a minute amount of graphite powder, (DRY LUBE?) to settle the new vanes in???

Teaspoonful of Graphite powder, acquired *if all else fails*, from a buddy with a Linotype machine, as used to clean their Spacebands!!! Chat Up, “Dick G” He The Man. Maybe.

Did you mark the position of the end cover for re-fitting?? in theory and originally, irrelevant, but after prolonged use, is that accurate across the inner/mating face, (same test) and may benefit from original position, refit possibly, the end plate is not that thick! and expansion and contraction (in use) is a potent enemy??? . Good Luck Mick.
Afterthought from a long time ago!! Would normally been with Engineers Blue, but even with a smear of printing ink across the mating face of the end plate, bolted up lightly with out rotating at all, and then removed, What pattern of coverage is transferred to the rotor, proving or disproving full, partial or irregular contact, to eliminate dodgy bearings, highly unlikely but possible.!!

This has probably been a confusing thread for those Kelsey owners who wonder what a vane is, and not a weather vane. Vanes used in the Gast pumps used by Miehle are carbon vanes. Here, from the December 1957 Inland Printer, is a Gast ad showing a cut-away picture of what these things look like: