986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Noticed Some Wobble on Crankshaft Serpentine Belt Pulley

jakeru · 08-25-2017, 10:10 AM

I've got some time to work on the Boxster today! Removed the old serpentine belt, and found some looseness/play in the power steering pump when rotated back and forth (exactly like described and video'ed in this thread: http://986forum.com/forums/boxster-general-discussions/61094-rattly-power-steering-pump.html ). Also, two of the three idler pulleys have small but noticeable rocking and bearing lash noise when rotated back and forth.

I'm actually not sure if that power steering pump rattling is problematic or not. Perhaps with the wobbling crank pulley, it "excites" this stuff which if the crank pulley were straight, isn't a problem? Worth a shot anyway, I think, (to just replace the wobbling crank pulley), before potentially tearing into the power steering system like contributor did here (he reported threadlocking the splined shaft to the vane pump was required to eliminate the spline play, and another used PS pump he picked up exhibited the exact same condition!)

The crankshaft pulley (when pressed both with hands and a prybar) exhibit no discernible axial (thrust) play. Not that I hooked up up a dial indicator to it to get a precise reading or anything, but nothing with crank play there subjectively seems amiss.

Although there is some evidence of some small oil leaking probably at the front crankshaft seal (behind the crank pulley), I'm but not sure how important that is (maybe this oil film has built-up over a very long time running without ever being cleaned.)

I'm in the middle of pressing bearings on the idler pulleys, and intend to put back together with a replacement, good used crankshaft pulley. Hopefully when that's done, it will take the wobble out and if I'm lucky, the metallic rattling noise!

If it doesn't take the metallic rattling noise away, I think I'll try "exercising" the power steering system while the rattling noise is happening to see if there's any effect.

Alternator seems tight, and water pump external appearance and pulley bearing also seem good - a bit of axial play, but (likely sleeve-bushing style) bearing feels tight! I think I see a 07/07/2011 date code, which is good to know it's probably not original water pump.

08-25-2017, 10:10 AM	#9
jakeru Registered User Join Date: May 2015 Location: Greater Seattle, WA Posts: 534	I've got some time to work on the Boxster today! Removed the old serpentine belt, and found some looseness/play in the power steering pump when rotated back and forth (exactly like described and video'ed in this thread: http://986forum.com/forums/boxster-general-discussions/61094-rattly-power-steering-pump.html ). Also, two of the three idler pulleys have small but noticeable rocking and bearing lash noise when rotated back and forth. I'm actually not sure if that power steering pump rattling is problematic or not. Perhaps with the wobbling crank pulley, it "excites" this stuff which if the crank pulley were straight, isn't a problem? Worth a shot anyway, I think, (to just replace the wobbling crank pulley), before potentially tearing into the power steering system like contributor did here (he reported threadlocking the splined shaft to the vane pump was required to eliminate the spline play, and another used PS pump he picked up exhibited the exact same condition!) The crankshaft pulley (when pressed both with hands and a prybar) exhibit no discernible axial (thrust) play. Not that I hooked up up a dial indicator to it to get a precise reading or anything, but nothing with crank play there subjectively seems amiss. Although there is some evidence of some small oil leaking probably at the front crankshaft seal (behind the crank pulley), I'm but not sure how important that is (maybe this oil film has built-up over a very long time running without ever being cleaned.) I'm in the middle of pressing bearings on the idler pulleys, and intend to put back together with a replacement, good used crankshaft pulley. Hopefully when that's done, it will take the wobble out and if I'm lucky, the metallic rattling noise! If it doesn't take the metallic rattling noise away, I think I'll try "exercising" the power steering system while the rattling noise is happening to see if there's any effect. Alternator seems tight, and water pump external appearance and pulley bearing also seem good - a bit of axial play, but (likely sleeve-bushing style) bearing feels tight! I think I see a 07/07/2011 date code, which is good to know it's probably not original water pump. __________________ 2001 Boxster Last edited by jakeru; 08-25-2017 at 11:08 AM.