speedometer cable problems

[zbane]

I am having a reoccuring problem with my speedo cable. It keeps breaking at the pinion gear (tranny mount). I have a 1979 280zx with the 2pc cable setup. One cable, about 1 foot in length, goes from the rear of the instrument cluster to the firewall, where it is connected to another cable. It is the longer of the two that keeps breaking, but I think the problem lies in the cluster. Here is why.

1. when it works, there is a rattleing sound from the dash.

2. the trip odometer is VERY hard to reset.

3. When the cable invariably snaps (at the pinion), you can hear the cable unwind. (by unwind, I mean unravel-like a spring releasing tension)

I think that if I were to pull the speedo cluster I could fix this by either cleaning and reinstalling, or simply replacing with a different unit.

I wanted to get our club's sage advice, however, before pulling the dash-by the way, how long do you think pulling the dash might take and hwo difficult is it?

Any Ideas?

Thanks

[zbane]

by the way, by unwind, I mean despoolling, unravelling, releasing energy. You can hear it spinning in its cable from inside the car, while driving (obviously). It's not so much that I need to see how fast I am going, I would just like to figure by gas mileage (and not get a speeding ticket). I am also not looking forward to pulling the dash-this is my daily driver and cannot be out of commision for very long due to a lack of dashboard.

[Doehring]

'cause I hate pulling the dash I also installed the 2 piece 280ZX solution. As the car is still under restauration I have no experiance how this setup will work, I only see some problems that the total cable length is much more. Now I'm a bit worried and so I'm also interested in the contribution of experianced Z owners. Thanks in advance.

Rolf

[sblake01]

Is is not possible to pull the the speedo without pulling the dash on a ZX? I can on my Z. I'm not too knowlegable on the intricacies of the ZX.

[zbane]

Not according to my service manual. According to it, I need to pull the steering wheel, everything attatched to it and the dash-all to get to two little screws on the underside of the cluster, what fun.

[IC1Lazo]

I dont know about you Z, but on my 83 280zx, I have to take off the steering wheel, combo switch and its covers to get access to the dash screws. Then I got to be careful in pulling out the dash gauge to avoid breaking any clips. I have already removed it several times due to my speedo cable breaking as well, but the only difference is on mine its the small cable that keeps breaking. I dont know if its the trans or the fubared shaft that the previous owner put in. The shaft had to be cut and welded to fit, I dont know why but I am now trying to research to see if the shaft from my parts 83 manual 280zx will fit it. I'm also probably going to have to replace the trans since it is leaking fluid and will start slipping when fluid gets to low.

[zbane]

I found the culprit regarding my broken speedo cable. In the attached photo I have circled a sensor that seems to creep into the cluster over time. It doesn't take much movement inward to block part of the mechanism inside. It seems that this blockage is what was causing my particular problem- I figured this out only after one had broken in there (good thing I had a spare). I found a couple small washers to fit, and this should fix the problem (I'll know once I order another new cable).