Wooly15 Posted December 31, 2016 Share Posted December 31, 2016 Im in the process of replacing my speedometer cable. The original one had completely broken off and was just flopping around inside the dash. I have the speedometer assembly out, and need to know if there are any additional steps I need to do to install this other than screwing in on. Should I apply grease inside the cable? Should I clean out the attachment point on the speedometer itself? Also, can I test to make sure it works with a low speed drill at the transmission end before reinstalling the dash? Any tips or tricks would be greatly appreciated. Picture still will not upload for me but I will keep trying. Link to comment Share on other sites More sharing options...
JohnD1956 Posted December 31, 2016 Share Posted December 31, 2016 I would test the speedometer while it is out. The new cable should be ok but any binding issue in the speedometer itself should be vetted before just assuming it is okay. Use the trans end of your old cable with the drill. Actually you may not even need the drill but it does make it fun to watch the barrel advance. I would also consider checking the 4 screws that attach the speedometer to the instrument panel, assuming you have the instrument panel out. Loosen each and then retighten lightly. There was a service bulletin about erratic speedometer readings being caused by binding with these screws. I would also check that the trip odometer reset tool works. It will go backwards by 100's of miles, and forward by tenths of a mile. Make sure the numbers work in both directions. It's no guarantee that the actual mileage counter works but if this one does not work you may as well fix it all right now. Link to comment Share on other sites More sharing options...
buick5563 Posted December 31, 2016 Share Posted December 31, 2016 Run the drill in reverse when checking. It is a counterclockwise gear. 1 Link to comment Share on other sites More sharing options...
Wooly15 Posted December 31, 2016 Author Share Posted December 31, 2016 Ok, thanks! What about lube? I know there's usually grease in cables and the new one is dry. Link to comment Share on other sites More sharing options...
JohnD1956 Posted December 31, 2016 Share Posted December 31, 2016 There is a speedometer cable lubricant at the NAPA, which is a very light, graphite immersed, liquid. It is not heavy grease. Usually put some in from the top side and it will self distribute. Link to comment Share on other sites More sharing options...
Guest Posted December 31, 2016 Share Posted December 31, 2016 You should only apply lube to the bottom third of the cable. It will work it's way up. If you lube the top of the cable it can work into the speedo itself and then you have trouble. Link to comment Share on other sites More sharing options...
FLYER15015 Posted January 10, 2017 Share Posted January 10, 2017 On 12/31/2016 at 0:53 PM, Tinindian said: You should only apply lube to the bottom third of the cable. It will work it's way up. If you lube the top of the cable it can work into the speedo itself and then you have trouble. Tin is absolutely right. Never lube a speedo cable from the top. They are wound so that they pump the lube UP the cable, and it is very easy to pump a bunch of grease right into the speedo unit. Very little moly grease at the bottom will do. Ask me how I know............... Mike in Colorado Link to comment Share on other sites More sharing options...
Wooly15 Posted January 14, 2017 Author Share Posted January 14, 2017 Finally got around to installing the cable I got from Summit. I installed it on the speedo and routed it through the side of those the firewall and forgot all about it. Stupidly, I forgot to check the length and reinstalled the dash, trim and all! Because I did that, Murphy visited and the cable was about 3" too short no matter how I route it. My first question...do you guys have a good source for a speedometer cable? Secondly, is there ANY way humanly possible to unscrew the cable from the speedo without pulling the dash? If not, I'm tempted to drill another hole so it will reach. @#$!%#!!!!!!!! Link to comment Share on other sites More sharing options...
old-tank Posted January 14, 2017 Share Posted January 14, 2017 Google "Speedometer Extension Cable" Link to comment Share on other sites More sharing options...
Wooly15 Posted January 14, 2017 Author Share Posted January 14, 2017 Update: I bit the bullet and pulled the dash and pulled the cable. I'm going to one of the local parts stores to find one that's longer. Most GM cables seem to be the same thread pattern for a lot of years. Fingers Crossed! 1 Link to comment Share on other sites More sharing options...
Wooly15 Posted January 15, 2017 Author Share Posted January 15, 2017 Found and installed a new cable and now I think I know why the old one was disconnected. Any idea what's causing this?: Was traveling around 20mph. Link to comment Share on other sites More sharing options...
trimacar Posted January 15, 2017 Share Posted January 15, 2017 The red area is on a drum, the drum is driven by input from the cable, something is binding and causing the drum to "catch"....needs to be removed and fixed, don't think there's any solution to fix in the car... Link to comment Share on other sites More sharing options...
Guest Posted January 15, 2017 Share Posted January 15, 2017 A possible cause is that someone over lubed the cable and grease got up into the head. Or maybe it is just old age and not neglect or improper maintenance. I wish you well in removing the head. I hate working under the dashboard. Link to comment Share on other sites More sharing options...
buick5563 Posted January 15, 2017 Share Posted January 15, 2017 Not neglect or anything else. It's just old and needs to be rebuilt and sent off to be rebuilt. 1 Link to comment Share on other sites More sharing options...
F&J Posted January 15, 2017 Share Posted January 15, 2017 4 hours ago, Wooly15 said: Found and installed a new cable and now I think I know why the old one was disconnected. Any idea what's causing this?: Your audio, it sounds like cable gets wound up, then lets go, then repeats.. Not the same exact symptoms, but I chased a speedo issue with a 40s Plymouth speedo.... On my car the needle would slam up/down to 0-40 with car barely moving. I reached under the dash while driving in the lot, and started loosening the cable nut. it did help a lot, but still not right. I was dreading removing the speed cluster, so I found a short one foot piece of inner flex cable to run the speedo with a reversing drill. It ran perfect with the drill at any speeds (these need to be reverse rotation, so you need a reversing drill) If you saved your old inner cable, just try spinning the speedo by hand. If the speedo is binding, you will instantly feel that; Then I looked really close at the inner cable in that nut, It was slightly bent. Ah Ha... So, I had a brand new generic inner cable kit from the HELP brand at auto stores. I cut and crimped to the exact length of the old one. I was shocked that the needle jumped just like before. So I reached under dash and kept loosening the cable nut a lot, then it suddenly ran perfect....even took it out on road at 55. long winded story, but I would try loosening the nut under the dash to test it. If the cable tip is too long, it puts stress on the magnetic drum that runs the speed indication part of the unit. That info was posted on a car site by a speedo shop guy, as the first thing to try. Link to comment Share on other sites More sharing options...
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