I have done searches and looked in the Tech section, but still don't have the info I really need to replace my broken tach cable. I have already tried to reach up behind the dash to find the clip or spring that keeps the cable in place, but my hands must be too large. All I managed to do was get really frustrated. I tried to get a look at things with a mirror and flashlight, but still no luck. All this was tried with the dash partly disassembled and the duct removed. I think that what I need is a picture of the back of a tach showing the clip that retains the cable. Is the clip always attached to the housing in the same orientation? Which way do you push or depress the clip to release the cable? I have read that one pushes up on the clip, and someone else says the clip is pushed toward the rear of the car. Has anyone ever made a tool that could be used from the engine side of the firewall? Any detailed advice or pictures anyone?

 

Here is a pic of the speedo with a tool attached its the best I can do tonight. I can take a pic tomorrow of the tach without the tool if you need. The spring clip is on the bottom. If you look close you can see how the tool pushes the clip in to release. The easiest way is remove the cable from the dist,have a helper push the cable lightly toward the tach,now you push the clip in,then have the helper pull on the cable.
I don't have a helper most of the time so I use a bungy cord as my helper.

 

IIRC you just push the tab in toward the back of the speedo and the cable comes right out. It helps if you can get yourself upside-down under the dash and look up at the guages.



Rick B.

 

That tool Roger shows is really cool. Would make the job a lot easier.

I replace the tach on my '74 a couple of weeks ago, and tracked it on another post. The summary is below, but the main thing is remove the drivers seat. Four bolts and you will be much more comfortable/productive.

Right as the dash ends, you can look up in there and see where the cable goes into the tach. I just stuck a long bladed screwdriver up there, and pushed the retaining ring into the tach as my son pulled the cable out (from the engine compartment). Took about five minutes.

To put the new cable in, I lined up the cable (this took about five minutes as well, and then my son pushed it in until it clicked. Surprisingly easy, though I may have just been lucky.

Points on this:

1) Remove the drivers seat. Not sure I could have done this standing on my head.

2) Remove the grommit at the firewall that the cable and other wires go through. You need the freedom to move the cable around.

3) I bought my cable from Corvette Central and it is a couple of inches longer than the cable I replaced. I set the distributor so it did not cause a bind, but I could see how the longer cable would be more likely to bind.

I took some pictures, and copied some from other posts to show what the cable to tach connection looked like, but I cannot figure out how to insert them into this post (says I need a url). I will stick them in my photo album for those who are interested.

 

Here is another pic of a speedo showing the clip.

 

Roger, those pictures are a great help. And the tool you made looks better than one I had imagined trying to construct. Mandingo, I have to admit that I never thought about getting the seat out of the way. I have had my head and shoulders in what little space there is in there, but with being somewhat large in stature, wasn't able to do much. As far as the new cable length, I had heard that replacement cables generally were not exactly right. Does any vendor supply one that is truly an exact replacement? I have one at the moment, but don't know how it compares with the original.

 

I replaced my tach cable by taking the top dash off and going from the top down. It was easy to remove but installing the new one was tough because I couldn't get enough leverage to push it past the clip.

I tried pushing it from the engine compartment and was able to get it clipped in. But when I started the car the tach didn't move so I had to mess with it. Turns out it was not seated properly at the distributor.

cc

 

That advice to remove seat is dead on ... been there. Moreover, since I've become older & rounder, it's a must.

Soon need to replace tach cable on a 71. The OE housing is AOK but core has become rounded at the tach end. I know about the "wrong" aftermarket cable lengths too. I plan to address this 71 by making up a new inner/core. Pull old core out from tach side & make up a new core. A local heavy truck shop has core & ferrules in stock & has tools/dies to square the core ends. I know shop manager & he told me to come on up & have at it. I've personally made up cores before but it's been at least 30 years since I've even thought about it. IIRC, the ends are a standard 0.104" square drive & seems like round core about 3/32"-7/64" OD. AC Delco & Standard Ignition used to sell cable assemblies & parts through local parts stores.

 

Seems like I read you can still get the factory length tach cables from some source. I found that out through forum searches a couple of weeks ago, after I had already purchased mine from Corvette Central.