Noisy BX Speedo

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Way2go
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Noisy BX Speedo

Post by Way2go »

Having now stripped the speedo from the Instrument Cluster, I can see the cause of the noise is not as straightforward as just a problem of a dry rotational bearing on the cable input.

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The metal drum system is attached to the plastic skeleton at only 2 points (North-South) which are spigots in the alloy casting of the input bearing and then peened over. There are no fixings in the East-West plane and the casting should just butt up against the plastic in this orientation.

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I say "should" but because of the uncentered leverage of the cable over the years, the alloy casting has bent over time in the East-West direction allowing the assembly to rock about the North-South fixings because the attachment is only a cruciform. The cable outer probably expands when the heater is on, pushing it more over to one side and hence why the problem goes away when hot.

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A couple of shots to show the extent of "lean" that the cable has caused over time.

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This is one of the only two points that the assembly can be tightened:

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That's not a screw its part of the casting. If both can be squeezed to make it tight it might cure it. Ideally the casting should be straightened too but that's a real breakage risk.

Basically the design is too weak for a cable bending into it in an East-West direction. I wonder if there is less strain on the LHD cars.

Shame really because this speedo is spot on against sat-nav and is non-jerky on the needle!
1991 BX19GTi Auto
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khan
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Post by khan »

I never seen this happen on LHD, maybe it's because of the layout of the firewall or the dashboard of the RHD cars or a bad reassembly sometimes in the past. anyway, I have a couple of speedos in good condition, I can send you one, but the problem is that u have to remove the needle and the black sheet with the speed reading, cause mine is in km/h. or maybe u can get one in good condition in a scrapyard near u
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Linegeist
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Post by Linegeist »

Drill out the spigots and insert machine screws.? :?
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MULLEY
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Post by MULLEY »

Just pop out the correct mileage drum, ensure the numbers are fixed in place by sellotape, so that when putting it into the replacment speedo head its all nicely alligned, that way you keep the correct mileage. How do i know this, i've done it, dead easy :D
2002 C5 2.0 HDI Estate - Jasmine - Now SORN
2011 Mini Cooper D Clubman - SOLD
2016 Mercedes A180D Sport - Auto refinement
1992 TZD Turbo - Bluebell - My daily
1991 Gti 16V - Blaze - crash damaged, will get repaired.
1990 Gti 8Valve SOLD - looks like it's been scrapped
2002 Mini Cooper S - SOLD - i miss this car
1992 TXD - Scrapped in March 2014
1988 CX 25 GTI Turbo2 - SORN
1996 - AX Memphis 1.5D - Dream - SORN

I'm not just a username, i'm also called Matthew.
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