Speedometer Cable

[Tony H.]

Hello folks,


The plastic tip of my speedometer cable from my 1970 Corvette broke off. Can these plastic tips be replaced with either another plastic tip or crimped-on metal tip? I really don't want to install a brand new cable/sheath if I can repair or replace the cable itself. Any help is appreciated.


Tony

[casey andersen]

Re: Speedometer Cable

Tony


The plastic tip can be replaced. Thet are available from GM or from NAPA. You just heat up the end of the cable, and slide the piece onto it. Good Luck! Casey Andersen

[Terry M.]

Re: Speedometer Cable

Yes the plastic end can be replaced with a crimp on end from a cable kit that I believe may even still be available from the GMSPO (GM Service Parts Operation). I will have to defer to Joe Lucia for the latest information in that department.


However here is the bad news -


1) Getting enough of the cable out of the sheath to make a good crimp may prove difficult.


2) The plastic tip is designed to be the "weak link" in the system and it is supposed to break first, so there may be other problems (speedometer head going bad, roughness in the sheath or cable going bad further up the sheath) requiring attention.


I'm not trying to scare you - taking the dash apart to get the cable out (assuming your car is 4-speed - I believe M-40 is a two piece cable) is no fun, but can, with care and appropriate manuals be done successfully by novices.


Terry

[Jack H.]

Also....

if memory serves, you'll find full inner cable drive assemblies listed in Corvette-Central or Dr. Rebuild catalogs. A new 'fresh' AC-Delco cable typically runs $30 and once you've got it you'll see an originality deduction because the ferrule that attachs to the distributor is gold dichromate vs. factory original zinc/cad....

[Joe L.]

Re: Speedometer Cable

Tony and Terry-----


The inner shaft ("cable") with tip(to be attached after cutting shaft to length) are available in two versions from GM:


GM #6477499------this unit is 70" long


GM #6478825------this unit is 145" long


I cannot find a reference for the tip, alone, but it may be available through GM's Delco parts system or NAPA as Casey suggested. However, I agree with Terry. If the tip has broken off, I'd remove the shaft from the casing to inspect for other problems and/or lubricate. Once the shaft is out of the casing, I sure wouldn't put the same one back in under any circumstances.

[Terry M.]

Re: Also....

Jack,


I guess I should look up GM parts terminology before I post, but I thought:


The cable is the inside part (that which turns).


The case (I mistakenly called sheath) that which does not turn and has the ferrule problems you addressed.


I am open to be corrected as I am in no position to get the parts books to look this up.


Terry

[Terry M.]

[Joe L.]

Re: Also....

Terry----


The "cable" nomenclature, as defined by GM, is SHAFT. The "case" is known as CASING. The CASING is not available seperately(without the SHAFT), but the SHAFT is available seperately, although only in a few lengths which must be cut to size and the tip attached.

[Joe L.]

Addendum To Above Post

As I looked in another GM reference which I happened to have handy, I see they use different nomenclature, so I guess they don't have a "standard" for this. In this reference, they call the complete assembly a "CABLE, w/casing" and the SHAFT is referred to as a "CABLE, less casing". They may have changed nomenclature over the years.

[JAT]

Re: 70 M40 two cables

Does anyone know why the 70 automatic Vettes have two separate cables which join together near the foot well of the drivers side before going into the firewall?

[Terry M.]

Re: 70 M40 two cables

Kind of a guess here JAT, but I think it is hard for the assembly line workers to attach the speedometer cable to the M40 as the body is being mated to the frame. The two-piece cable put the junction at a better place for them - not us.


Terry

[Jack H.]

Re: Addendum To Above Post

That's why I made my post. Plus, the 'vernacular' used in the parts business and swap meets points to the full assy as a 'cable'. Wasn't trying to 'rain' on the early parade of this thread -- just wanted to point out a potential 'opps' that could result from loose/confusing use of terminology -- being helpful....

[Jack H.]

PS

For those who have purchased the Delco service replacement cable asssy, all is not lost. You can slide the ferrule to the mid-point of the cable/sheath, mask the cable/sheath, spritz the ferrule with a blaster, and go for a quick 'swim' in your Eastwood home plating tank to lay down fresh zinc/cad plate and recover to a factory original appearance for the assy....

[Terry M.]