wobly speedo

Post by **5lab** » 28 Mar 2005 11:55 pm

having fitted my speedo cable (in gratitude to redline) i've now got a wobbly speedo - it bounces a huge amount at around 10 mph - and seems to dissappear nearer 40.

any thoughts??

also, the car makes a 'woooo' noise from (i think) the front left of the car, which starts up at around..mmm.. 30 mph, and gets louder. seems to get lesser on the far side of bumps.. and on corners. i thought it was the bearings but they seem fine.. no play or roughness when turning the wheel by hand. again, any thoughts?

Post by **V6 Man** » 29 Mar 2005 12:55 am

Wobbly speedos are commonplace with cable driven units - try squirting WD40 down the cable inner to see if that frees it up.

The noise does sound like a wheelbearing. Even though there is no play they can run dry and start to whine - I had this on my 340 and even repacking with grease didn't cure it. Bearing kits are cheap anyway and the chances are it's only the outer bearing that's wearing.

Post by **RandomHero** » 29 Mar 2005 08:41 pm

Remember WD40 attracts moist. If it's freezing (not very likely though) the cable gets frozen and when drive away it will probably get broken. I have the same problem sometimes, just speed up and it disappears

Funny thing is it disappears in my car too around 40 km/h, the same amount in miles. But miles are more then kilometres..... You'd better use some kind of chain oil..

Good luck!

Post by **daffodil** » 29 Mar 2005 08:46 pm

i remember this.....the volvo technical bulletin had a part no for a spring, it was about the size of a pen spring and was inserted into the cable at speedo head end....try it and see what happens

Post by **shimon340** » 29 Mar 2005 11:57 pm

hi

a jumpy speedo at low speeds is likely caused by a bad earth on the car. check the earth strap from the battery to the body and the one that connects from the bonnet to the front cross member. bas earth cuases jumpy speedos....

hope this helps

as per the noise, without hearing it, i would guess it was a bearing that has worm out...

shimon

Post by **Fuse** » 30 Mar 2005 12:53 pm

How would bad earthing cause a wobbly speedo if the speedo is mechanical as it is in 300-series.

Speedo will work without electricity because there's just a cable going to the front wheel.

Post by **shimon340** » 31 Mar 2005 09:00 am

the speedo system in the 340 isnt mechanical. it has a cable pick up with a small peg that connects to the front wheel hub but the system is a magnetic induction system hence a bad earth causes the speedo to jump at low values.

however, if the speedo goes to high speed values when the car just starts moving and stays at those values but then drops as the car speeds up, then the magnetic unit in the speedo itself is faulty and needs replacing. this same sympton affects the 240 and 740 speedo systems also.

the fully electric systems were introduced on the 400 series which uses a pickup signal on the garbox and a FM encoded speed signal which is then trnslated into a linear movement of the speedo needle.

so, if the speedo is jumpy, check the earth strap from the engine to body and from bonnet to front bar above headlamps. a clue that the earth id bad is a inconsistant flashing light on the fuel gauge ( it doeesnt flash on and off but blinks intermittantly and rapidly ) and also a stiff choke leaver or heater tempoerature control. when the earth from the instrument binnacle fails, the system earth through the choke and temperature selector. This causes the wire to heat slightly, heating the nylon or plastic cover of the cable and making the wire and cable stick together. A stiff choke can be somewhat resolved by oiling the linkage on the carb or throttle but the heater can only be remidied by sliding the selector a lot......

.
did you manage to get the speedo sorted?

shimon

Post by **Lonewolf** » 31 Mar 2005 11:19 am

i'd suggest using a dry (graphite powder) lubricant, as that seems to be what i rubbed off it accidently when replacing it once.

Post by **5lab** » 31 Mar 2005 11:20 am

lonewolf - if you've taken the alloys off your old car, would you be interested in selling me the centre caps from your old alloy wheels? the little ones with the v in the middle??

Hugh

Post by **Lonewolf** » 01 Apr 2005 02:29 pm

lol i would be 5lab, theres one problem, only 1 wheel had the centercap when i bought it. At best there might be 3 caps, 1 from the wheels, 1 from my spare and 1 from my 2nd spare from my original 360, and the condition of them isnt perfect either, the epoxy having partly glazed over at least one of em sorry.

Post by **5lab** » 01 Apr 2005 02:33 pm

ahh never mind then. still after a complete set. hint hint duvel

Post by **Grendel** » 12 Apr 2005 03:25 pm

Sorry for butting in but Speedo on my 340GL is also jumpy at below 45mph and the mile counter stopped turning about 2 years back any idea what it could be? I took to a mechanic but he could not find anything wrong with the cable. In addition, at the same time it started happening most of the dashboard dials died except the fuel gage? Any idea what is wrong? Admittedly, last time the mile counter worked it said 150K+ on clock but that was 2 yrs ago so could just be all worn out.

Post by **petefarrell360** » 12 Apr 2005 09:44 pm

Hi, I believe the mileage recorders sometimes lock up completely, probably from worn parts. I've never seen it yet, but I know the only simple cure is to replace the unit.

Today when I pressed the trip reset button after filling up with fuel I noticed about 10 miles later that it had only turned 0.9 of a mile! So pressed the trip reset button again and now all is well, so this may be the first sign that mine is on the way out, hopefully not, probably just the button didn't let the parts re-engage properly.

As your other dials aren't working, I would suspect that it is something else to blame. I know the actual needle is not dependent upon power, as that will record speed with out power, as it is a mechanical device, the mileage recorder I don't know about. So it may be worth checking the multiplug behind the dash, as other dials may also not be getting power. The pins may have bad contacts or the whole plug may be partly pulled out. If you remove the cover from under the dash above the pedals, then lay in the footwell looking up at the back of the speedo, you'll see two long white plugs entering the lower part of the back of the speedo unit. The one on the right as you look at the dials is probably the one to blame as I believe it supplies the power but I'd check both.

Pete

Post by **Grendel** » 13 Apr 2005 10:52 am

Excelent stuff. Thanks for that i shall give that a go to see if it fixes the problem. Many Thanks