tim hunt Posted March 31, 2019 Report Share Posted March 31, 2019 My speedo has suddenly developed an annoying fault. Up to an indicated 30mph the needle oscillates about the actual speed over a range of about 5mph. Oddly at any speed from 30 to 70mph the needle is still rock steady. Has anyone had a similar issue and found a fix? Tim Quote Link to post Share on other sites
RogerH Posted March 31, 2019 Report Share Posted March 31, 2019 Hi Tim, very possibly just needs a simple oiling. Remove the cable and clean/degrease. Apply a thin oil and wipe off excess. Keep the oil away from the top 6 inches or so. Possibly consider a dry lubricant Roger Quote Link to post Share on other sites
ctc77965o Posted April 1, 2019 Report Share Posted April 1, 2019 could be a unusual bend in the speedo cable..has it been disturbed during maintenance? Quote Link to post Share on other sites
ianc Posted April 1, 2019 Report Share Posted April 1, 2019 How often do you drive the TR at below 30 mph? I have always driven my TR on the tachometer, with the speedo there to make the car legal and to provide mileage readings. The needle of my speedo, if ever I bother to glance at it (it's located in front of the navigator), is always wobbling about - but so what! Ian Cornish Quote Link to post Share on other sites
John L Posted April 1, 2019 Report Share Posted April 1, 2019 I had a similar problem with a rev counter, the input shaft was quite hard to turn, I used some carb/brake cleaner carefully on the input shaft, turning the shaft with a small screw driver, that has cured it. Holding the speedo with the glass uppermost so the cleaner and dirt drop out not into the speedo! Quote Link to post Share on other sites
tim hunt Posted April 1, 2019 Author Report Share Posted April 1, 2019 Thanks to all for the pointers/advice. I will investigate and report back in due course. I take your point Ian but one is < 30mph quite a bit in urban areas and the oscillating needle is in my peripheral vision and annoys me. Tim Quote Link to post Share on other sites
Bobble Posted April 2, 2019 Report Share Posted April 2, 2019 (edited) I had a similar problem with my speedo and rev counter. The rev counter issue was solved by fitting a new cable. However, the speedo was a different matter - apart from a 10% inaccuracy in the reading the needle would bounce all over the place (up to 60) when travelling very slowly. I tried everything - removing inner cable, cleaning, greasing, changed cable and angle drive. No improvement whatsoever. Eventually sent the whole thing to Speedograph Richfield in Nottingham. They will re-condition the speedo and re-callibrate but you will need to send them details regarding axle ratio and tyre size. It now behaves perfectly and gives the correct speed. The cost was around £70 (inc. VAT) but you will need to send it by special delivery (for insurance) at about £9. Like you Tim I couldn't live with the needle bouncing about at lower speeds and the inaccuracy was annoying too. Worth considering. Bob PS They also fixed my ammeter which refused to budge from a reading of +30! Edited April 2, 2019 by Bobble Add a new line Quote Link to post Share on other sites
ianc Posted April 2, 2019 Report Share Posted April 2, 2019 I can understand the annoyance caused by an oscillating needle right in front of the driver. The advantage in having the speedo located on the far left (it would have been the left side of the locker lid, if one were there) is that it is well out of my sight! Ian Cornish Quote Link to post Share on other sites
tim hunt Posted April 24, 2019 Author Report Share Posted April 24, 2019 An update. As a first step, before condemning the instrument itself I checked the cable run. It was well supported but not pinched anywhere with no bend radius below 6", in accordance with the Smiths Instruments recommendation. I removed the flexible drive and cleaned it thoroughly, it was quite dry. I did notice some shiny areas where it must have been rubbing on the outer at some time. There were no areas of damage however and no kinks. It also passed the test in which when allowed to hang between the thumb and forefinger of each hand with a loop of ~9" diameter, it could be rotated smoothly with no snatching. I lightly lubricated the flexible drive with a lithium based bearing grease, equivalent to the Castrol LM recommended for the purpose by Smiths and then reinserted it. I then withdrew it by 8" and removed all traces of grease from the instrument end of the drive. I reassembled and can report that on a test drive the speedo needle behaved perfectly, giving a completely stable reading at all speeds - Result! Flushed with success I treated my tacho drive similarly. Incidentally Smiths recommend that instrument flexible drives be examined and re-greased every 10,000 miles - I wonder just how many owners do this. Tim Quote Link to post Share on other sites
RogerH Posted April 24, 2019 Report Share Posted April 24, 2019 Hi Tim, well done. You realise it wasn't the cleaning and the new grease that did the TRick but the fact that you held it and spoke to it. They have feelings you know. Roger Quote Link to post Share on other sites
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