john niedzwiecki Posted May 31, 2017 Report Share Posted May 31, 2017 Hi all just went out in my tr4a after about 3 months and the speedo not working it was before where do I start first or what can it be Quote Link to post Share on other sites
Don H. Posted May 31, 2017 Report Share Posted May 31, 2017 Could be a number of things. Shouldn't be too hard to isolate the problem. I'd suggest you use the troubleshooting guide in this vintage publication on the care of Smiiths Instruments: http://vintagebritishcables.com/documents/SMITHStheCareofInstruments.pdf Quote Link to post Share on other sites
RogerH Posted May 31, 2017 Report Share Posted May 31, 2017 Hi John, if you have an angle drive out of the gear box (you should have) then it could be that, it often is. However if you undo the speedo cable from the back of the speedo then you will have access to the inner cable. TRy and rotate this with your fingers - if you can then either the speedo cable or angle drive is duff. Pull the inner cable out and examine the end of the cable - if it is broken then you have found your problem. If the cable is in good condition then the problem is n the angle drive. If you are lucky then there may be an access panel on the side of the gearbox to get tot he angle drive. Remove drivers seat, lift up carpets and look for the access panel. Roger Quote Link to post Share on other sites
boxofbits Posted May 31, 2017 Report Share Posted May 31, 2017 (edited) If the cable is broken there might be good reasons for that. On my particular 4a the cable spigot had partially seized in the speedo housing causing excess torque on the cable. You would have to remove the speedo and have it serviced. Kevin Edited May 31, 2017 by boxofbits Quote Link to post Share on other sites
8iggles Posted June 20, 2017 Report Share Posted June 20, 2017 If you find the angle drive broken then investigate the root cause otherwise if you replace it it may quickly brake again. This happened to me. You don't want to do this job twice. Check the cable first. My problem turned out to be the speedo itself. The fact that your car was stood for a while may point to the same problem: There is no bearing in the speedo. The steel drive shaft rotates in the aluminium (sic) casting. I found mine almost stuck. Very simple fix. Cleaning up and a little Vaseline and the speedo works smooth like it never did prior. Just a thought... John Quote Link to post Share on other sites
PYU940F Posted June 21, 2017 Report Share Posted June 21, 2017 Yep, all basic stuff do investigate, a bit fiddly so check the easy bit first which is the drive into the back of the speedo. If your steering wheel has enough space to pull the speedo out of the dash I find it easier to fiddle with the cable with it pulled forward. (two knurled nuts keep it in place). If the angle drive is duff then ensure that a brass washer is installed in the input side of the unit. A lot are not and apparently it causes stress on the angle drive if not installed. I replaced mine just recently but previous threads have suggested that the new replacement units are unreliable and not of good quality. Mine works (at the moment) but previous threads have suggested that you can get your old angle drive overhauled but I cannot remember who does them. I still have my old original drive in my tool box if anyone wants it to fiddle with. Cheers Simon Quote Link to post Share on other sites
TR NIALL Posted June 21, 2017 Report Share Posted June 21, 2017 Yep, all basic stuff do investigate, a bit fiddly so check the easy bit first which is the drive into the back of the speedo. If your steering wheel has enough space to pull the speedo out of the dash I find it easier to fiddle with the cable with it pulled forward. (two knurled nuts keep it in place). If the angle drive is duff then ensure that a brass washer is installed in the input side of the unit. A lot are not and apparently it causes stress on the angle drive if not installed. I replaced mine just recently but previous threads have suggested that the new replacement units are unreliable and not of good quality. Mine works (at the moment) but previous threads have suggested that you can get your old angle drive overhauled but I cannot remember who does them. I still have my old original drive in my tool box if anyone wants it to fiddle with. Cheers Simon AlanT on this Forum will repair your old Angle Drive. Quote Link to post Share on other sites
PYU940F Posted June 21, 2017 Report Share Posted June 21, 2017 PS Do not be tempted to change the angle drive from underneath the car, it looks possible but it ain't. You will just spend a messy morning achieving nothing. Gearbox cover off job (deep unjoy) or, as said, if you are lucky (deep joy) you may have a cover with an access panel at the back on the driver's side (RHD). I have also seen cars with the speedo and tacho positions reversed.so the cable routing is all wrong putting strain on the inner cables. The speedo should be on the left of the tacho on RHD cars. I wonder how many were installed arse about face after a restoration or conversion from LHD. Be interesting to hear from members. Simon Quote Link to post Share on other sites
ChrisR-4A Posted June 21, 2017 Report Share Posted June 21, 2017 +1 for Speedo ceased, I've had two new ones. Original unit just stopped working, worn out? First replacement lasted just over 3000 miles then ceased, second replacement has been good for over 10 years so far. Also had angle drive fail with short bit of cable joining it to gearbox was worn. Replaced with piece of carefully ground Allen key about 20000 miles ago and still going ok. Quote Link to post Share on other sites
PYU940F Posted June 21, 2017 Report Share Posted June 21, 2017 "Replaced with piece of carefully ground Allen key about 20000 miles ago and still going ok" Love it, will be better than the original design. Will send you my old original drive and you can go into business producing service exchange drives that last. Simon Quote Link to post Share on other sites
ChrisR-4A Posted June 25, 2017 Report Share Posted June 25, 2017 Simon, there is somebody doing that now,see prior post re Alan Taylor, he's your man. Regards Chris Quote Link to post Share on other sites
arky_MGB Posted January 14, 2019 Report Share Posted January 14, 2019 How can I contact Alan Taylor? I found this site because my 73 MGB has the same issue. replacement angle drives fail pretty quickly... Quote Link to post Share on other sites
RogerH Posted January 14, 2019 Report Share Posted January 14, 2019 Hi Arky, you could simply PM 'AlanT' With luck Bruce Martin may come in and give some good info on the angle drives. You could contact CaerBont automotive in Wales. They have all the Smiths manufacturing equipement and make good angle drives. https://www.caigauge.com/ Roger Quote Link to post Share on other sites
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