Help! 1970 Speedo cable help!

[Bolisk]

I have a very early 1970 Corvette (Feburary). I also have the 1970 Corvette assembly manual. One of the things that I have noticed is that on several occasions, the assembly manual (especially the "updated" pages) do not match how my car was assembed.

Case in point, the Speedo cable routing. My 1970 assembly manual shows the speedo cable being sent through the firewall via a gromet to the right (looking aft) of the master cylinder (e.g. between the drivers side fender and master cylinder). Form there the cable goes straight into the back of the speedo.

This is NOT how my car's speedo cable is routed! There isn't even a hole in the firewall, where the assembly manual says there should be one. My car's speedo cable enters the firewall about a foot directly lower than where the tach cable & oil pressure line enters the firewall (on that angled buttress on the opposide side of the master cylinder). From inside the car, the speedo cable enters the foot box to the right of, and sligtly lower than the steering column. Is this right? Is this how the 1969 cars were routed? I'm guessing that my car is so early that it still has some of the 1969 parts on it. . .like maybe the firewall.

My next and last question is, if the above is correct, how / where do I rout the speedo cable in the dash? If I attempt to rout the cable behind the break and clutch than up to the dash. . .it reaches, but it interferes with the clutch pedel operation. Do I rout it between the break and clutch, or between the accelerator and break? Does it go over the steering colum, or under. . .etc. . .etc. . .

Thanks for any help I can get!!

Best Regards,
-Bolisk

 

[Bolisk]

Wow! Have I finally stumped everyone!? :L

 

[6880 Mike]

I checked my '68 AIM last evening. Speedo cable comes directly out of the cowl grommet to the driver's left of the master cylinder, and drops pretty much straight down to the second half of the cable. Second half of the cable routes back to the speedo gear on the tranny.

Tach cable leaves the firewall at the indent, through a grommet which includes the oil pressure gauge line and the electric line for the back up light switch (possibly other accessories). Tach cable and oil pressure line route directly to the engine from the firewall grommet.

Neither cable should cross the steering column. Speedo and cable are on the driver's left of the column; tacho and cable are on the driver's right.

 

[TimAT]

I just put a new speedo cable in the 74. Had a hole left and below the master cylinder. Regardless of that, if you route the new cable AWAY from things that are hot or will rub on the cable, keep the bends in a large radius, it'll work fine. Correct length for the 74 with no cruise control is like 72 inches.

 

[Crimson Thunder]

The cable on my March 8 built 1970 enters the firewall the same as yours.

 

[Vettehead Mikey]

and drops pretty much straight down to the second half of the cable. Second half of the cable routes back to the speedo gear on the tranny.

Just for you to know, two piece cables are for cars with cruise control. The transducer is inserted between the upper and lower parts of the cable.

Your car originally had a one piece cable.

 

[Bolisk]

I stumbled across the answer in a Paragon catalog.

The 1970 Automatic trans cars have the cable go strait out the firwall to the left of the master cylinder. It then drops straight down and it's a two peice wire.

The 1970 4-speed cable is routed exactly as my car has it, and it's a one peice cable.

Evedently my assembly manual does not cover the manual transmittion install of the speedo cable!

Paragon's catalog clearly showed the routing differences between the two transmissions. If you have the four speed, the speedo cable gets routed over the steering column, and in front of the break and clutch pedals.

Thanks for eveyones imput.

-JR

 

[Bolisk]

Correction on my last post.

The speedo cable is routed over the steering column, and between the break and clutch.

 

[JohnZ]

Evedently my assembly manual does not cover the manual transmittion install of the speedo cable!-JR

I'm sure it does, but you have to know where to look - the speedo cable routing for a 4-speed (the base condition) is shown in the electrical section (UPC 12).