Speedometer cable removal for clean and lube

[Larry M.]

Since the speedometer needle on our 1972 bounces wildly from 50 to 120 when driving above 40mph on cold days (below 40 degrees), and since the lower left instrument panel is currently out of the car exposing the speedometer end of the cable, I'd like to disconnect it at the 4spd transmission end and pull the cable out of the casing to clean the casing (brake cleaner and compressed air) and lube the cable.

For any of you who have done this, did you encounter any unexpected difficulties on re-installation pushing the newly lubed cable through the length (and twists and turns) of the casing?

Thanks for any info.

Larry

[Harry S.]

Re: Speedometer cable removal for clean and lube

Might I suggest you pull the outside cable also and clean the inside. There is most likely dried grease in there also.

[Larry M.]

Re: Speedometer cable removal for clean and lube

Harry,

Thanks; yes, that's part of my plan.

Larry

[Richard G.]

Re: Speedometer cable removal for clean and lube

Never heard of anyone having issues getting it back in.
If you do it likely requires replacement.
What are you going to use as a lubricant?

[Larry M.]

Re: Speedometer cable removal for clean and lube

Richard,

Thanks; I haven't decided on any specific lube as of yet, but it seems there are a number of commercially available ones for me to choose from (do you have a recommendation?).

From reading previous threads, the consensus seems to be that no matter what lube is used, it's best used sparingly.

Larry

[Paul D.]

Re: Speedometer cable removal for clean and lube

My suggestion would be to disconnect the housing from the trans and seal the end with a plastic baggie or rubber cap then fill the cable housing with whatever cleaner you choose. WD-40 or something like it would probably evaporate slower allowing more working time. I would then reinsert the inner cable and spin it with your fingers and slide it up and down to loosen any buildup in the housing. Then remove inner cable, blow out the housing and really clean the inner cable. Check for any signs of fraying on inner cable and replace if you find any. My rule of thumb is to lube the lower half (towards trans) of the inner cable only as enough will rub off as you reinsert to lube the upper half. You do not want excessive lube at the speedo head. The lube I use is from a (30+ years) old can of GM Lubriplate that may or may not still be available. Any good quality white grease should work though. As stated above, if binding is still detected while spinning with your fingers after cleaning and lubing, you probably have housing issues.

[Larry M.]

Re: Speedometer cable removal for clean and lube

Paul,

Thanks for your suggestions. Since there haven't been any replies of problems reinstalling the cable, I'll expect none when I get to it.

I've

[Tom E.]

Re: Speedometer cable removal for clean and lube

Larry,
I had some needle bounce after a complete restoration and using a replacement cable and housing. I had lubricated it lightly before installing but still had appreciable bounce. I disconnected at both ends and then pulled the cable out, lubed down the entire cable with chevron black pearl extreme pressure grease. I used it sparingly especially near the speedometer end. The cable slid back in easily and I was able to reinstall the connection at the speedometer with minimal effort. Did not remove seats or anything else. Needle is now steady at any speed. Hope this helps.
Tom

[Larry M.]

Re: Speedometer cable removal for clean and lube

Tom,

Glad to hear you had no issues; thanks for letting me know.

Larry

[Paul D.]

Re: Speedometer cable removal for clean and lube

Larry, the cable should go back in with minimal effort. Push it in until it stops. If tip is not close to flush with the housing end, turn the inner cable while applying light pressure until cable seats in the speedometer gear. If the cable does not slide in easily, try to visually inspect the housing looking for crushed, kinked, or burned (melted) areas.

[Larry M.]

Re: Speedometer cable removal for clean and lube

This task turned out very well.

I unscrewed the cable casing at the transmission end to remove the sharp bend going into the trans, and the inner cable pulled out easily from the dashboard end. I sprayed brake cleaner and Aerokroil through the casing to break down and flush out any build up (didn't see much debris coming out of the trans end; primarily liquid).

After wiping the cable down I slid it in and out the length of the casing several times, wiping it down after each insertion, in case that would catch any build up. Final step was a very thin application of white lithium grease, and then connection back into the trans.

It'll be 3 or 4 weeks before the car can be driven again, so I won't know until then if the bouncing needle issue has been cured.

Thanks for all your input on this.

Larry

[Bob B.]

Re: Speedometer cable removal for clean and lube

Larry and all,

Too late for your issue since the cable has been taken out and reinstalled, but make cure the cable nut to the speedo (or tach if it does the same or makes noise) nut is completely tightened down so the cable is completely seated. That's not always obvious just by looking.

Bob

[Larry M.]

Re: Speedometer cable removal for clean and lube

Bob,

Thanks for that tip. However, the speedo and tach connections on our '72 (and I'm guessing all C3s until the gauges went electric) are effected by pushing the cable casing into a snap-spring connection on the back of the gauges, not via a screw-on method.

I'd be willing to bet that a screw-on method would be much easier than the push-on that I had to do. I had to be in a very awkward position, and push hard against the spring clip to overcome its tension. With sharp metal edges on the clip, it was very painful on my fingers. I would have greatly preferred something I could screw into place (like down at the transmission connection).

Larry

[Bob B.]

Re: Speedometer cable removal for clean and lube

Larry,

Thanks for YOUR tip! I have a '69 project that is ways from doing the dash, but i'll remember that. It's a 427/390, red/red, hardtop/convertible, and has most options except for a/c.

Bob

[Lawrence S.]

Re: Speedometer cable removal for clean and lube

Use graphite lube if you can find it. I recently did this with a tach cable and used graphite and very little moly lube. I have had good results.