Forum bmwbike.com

Previously I had the problem of the bottom tube of the rear plunger hanging up on the tube above it (which it goes into) So I took everything apart, bought a new tube, (as the old one got crushed), put it all back together, making sure the long center plunger tube was tapped down tight, and both pinch bolts tight...... I think I went as far as 1 km and the same darn thing happened, the bottom tube is caught and crushed from its mating tube. I checked the main center tube and it was still tight, as I could just see it protruding out the bottom...

Is there something I'm doing wrong??? Please help... thanks!!

Hello again Stacey, If you have a parts book that shows assy sequence and right parts this should not be possible to occur.Here is my suggestions, starting with the lower sleeve there should be a thin wave washer inside first, then a flat steel washer(sometimes two),now this is the MOSTimportant point these must only fit onto the small diameter at lower end,so when tube is right down & pinch bolt tight it cant move, there is also a rubber buffer. good luck. Lets know if this is not clear.Geoff.

Hi Geoff,

I do have the parts book and I did install the wave washer first, then flat washer, then rubber buffer into the bottom cup, tapped down the big middle pin and tightened the pinch bolt. When this was done, I couldn't spin the lower tube (so everything was down tight) but the shock must hyperextend (open up past the 2 tubes, and for some reason, mine catches and collapses the lower tube....???) Maybe I have to order a 6-pack of these bottom tubes.... Also, this is happening on the driveshaft side. Any other hints, or something I'm missing?....

Did you replace the suspension bushes? If they are worn and "sloppy" it could be that under load the drive is moving slightly, just enough so that the lower cover moves forward and catches the edge of the upper cover.

Hello Stacey, have you checked these ? the free length of spring(145mm) for solo use, length & Diam. of lower sleeve mine are, 57 long & 40mm O.D. on an assemnbled bike only 15-20mm of lower sleeve is showing so about 40mm are inside other one, hard to imagine it getting out so far.Good luck & lets know what you find as I have 3 plunger bikes.Regards ,Geoff in Australia.