Nelsontr Posted March 26, 2012 Report Share Posted March 26, 2012 I have an issue with the speedometer in my '80 210 (b310 series), doesnt read accurately at all... as soon as i start moving it bounces up to like 30 or 40 mph. just replaced the cable over the weekend and the issue persists. i was wondering if i should tackle this problem from the dash side or from the tranny side first. anyone have a simular issue that they were able to resolve? Quote Link to comment
datzenmike Posted March 26, 2012 Report Share Posted March 26, 2012 You replaced the complete cable assy? Well look for a tight bend and straighten out as much as you can. Was the new cable lubricated? Quote Link to comment
Nelsontr Posted March 26, 2012 Author Report Share Posted March 26, 2012 Yeah, we actually lubed it up right before installing the cable assembly... and it seems that there are not many bends to the cable as is. Where would you look for problems, the gauge or the tranny? Quote Link to comment
datzenmike Posted March 26, 2012 Report Share Posted March 26, 2012 Usually the inner coil will very momentarily snag on a tight bend, on any rust or damage or if dry. The transmission keeps turning the the coil keeps storing energy like a rubber band until it jumps loose and releases giving the speedometer a big kick and the needle jumps. You changed the outer sheath too? Quote Link to comment
Nelsontr Posted March 27, 2012 Author Report Share Posted March 27, 2012 the whole cable assembly was swapped out... havn't touched the gauge or anything on the tranny, yet. so, it sounds like it is getting bound up in some spot. do you think re-lubing would hurt anything? we used the lube that came with the speedo, at the time of installation . Quote Link to comment
datzenmike Posted March 27, 2012 Report Share Posted March 27, 2012 Won't hurt anything but you probably did it just fine. Quote Link to comment
blackwolf Posted October 1, 2012 Report Share Posted October 1, 2012 i've got a 84 720 doin the same thing just took it apart and ended up breakin the speedo needle fml...i jack up the back end and put it in gear and watched the cable end spin never jumped or anything so im guessin the speedo head is A. dry or B. worn out but need a needle to figure that out....tryin to glue it back together any sugestions on gauge set ups if glue dont hold?? Quote Link to comment
MikeRL411 Posted October 2, 2012 Report Share Posted October 2, 2012 A rare mishap, but it happened to me. Shortly after my son entered a "spirited" fun run, the copper drag cup inside the speedometer cracked [incompletely which confused the diagnosis] the solder joint to the speedometer drive stub inside the speedometer housing. Erratic readings to say the least due to the fact that it didn't completely separate, just enough to tilt the copper cup while the permanent magnet spun like it was supposed to. The geometry between the spinning permanent magnet and the copper drag cup on the speedometer main housing plus the return spring [which God forbid never fails] determines the needle position and saves your posterior from sitting still while the Highway Patrol writes up your speeding ticket. As a side remark, while adjusting the copper cup position for resoldering to the main shaft the speedometer shop told me they had to readjust the position because the speedometer was reading 10% high, I said "No way!" now my kids will think they are doing 60 in a 55 MPH zone and I won't have to bail them out at 2 AM. I still haven't told them about my little deception. 1 Quote Link to comment
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