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Hello all

Ive had an intermitent fault with the rev counter on my 638 110cdi. On tick-over the counter begins as normal, then falls to a mm or 2 off 0. Im not sure but to me thats not a correct reading. When traveling ovre 20mph the guage initially goes up then falls down. I havent visably seen the guage go over 3000rpm, although I never rev the nuts off any vehicle Ive had. But when travelling, it does seem to hit 0 fairly quickly, with occasional jumps on the guage. I took the old crankshaft sensor out, noticed it was rusted down the plastic shaft, cleaned and replaced. For 5 minutes it seemed to cure the problem, then it returned. I bought a new sensor and it again, appeared to work for 5 minutes then the problem returned (most upset about that)! Has anyone had this problem? Im wondering if the flywheel needs a clean (as the original sensor had a bit of muck on it) OR if its the harness OR perhaps the dash connection/guage itself. Does anyone know the voltage reading to the sensor?

Im looking to remove the pollen filter as I have no idea if its EVER been done. Any ideas where I need to look? Usually under the glovebox side of the dash panel, but Id rather know beforehand for sure before I go taking the panel off.

Also, last question, for now!: has anyone experienced a knocking noise on the front offside wheel? Sounds like the wheel cover is loose but its not. Just had the driveshaft inner gaitors done, mechanic said bearings seemed fine and the noise doesnt appear like bearing noises do, its only when going over a large bump or under stress of the wheel.

Ta muchly.
 

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Nor sure about the crankshaft sensor issue, so can't help there but the suspension knocking could be either the anti-roll bar bushes or the droplinks. Both wear out and need replacing from time to time.

have a search on here re: the pollen filter, there's lots of info about it, but be prepared to lose some skin off you knuckles!
 

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try these 2 sets of notes about pollen filter, they originally come from this forum.

Wheel noise:~ possibly cv joint or intermediate bearing or gearbox output bearing.
2 cv joints (obvious where they are)
intermediate bearing is in chassis member just before outer end of shaft that goes from gearbox to inner CV joint.... should have no play.
Gearbox output bearing:~ inside gearbox where the intermediate shaft enters.... has tendency for mounting hole to go oval.

can supply pdfs if wanted

also check bottom "king pin" type bearing under the wheel hub... it should be very difficult to "waggle"
 

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