razman

i'm getting ready to put dash panel back in car, i temporarily put a cable on the back of the speedometer and manually turned it to see if speedo responded. it did, but made a bit of a whining (dry) noise as i turned the cable. should speedometer be lubed? if so, how and with what? thanks, Rick

Easy Mike

Lube the cable.

7T1vette

DO NOT lube anything in the speedometer. That lube will just collect dust over time and result in the mechanism binding up. If you lube the cable, just put a dry graphite power/lube on all of it except the last foot of cable just before the speedo head.

4SPDL81

Willcox has excellent info concerning speedo lubrication on their website...good luck....

razman

i checked Wilcox site, only found info on lubing the cable. did i miss it?
this is a brand new cable, works very freely, i hooked it up to speedo and chucked it into drill motor to see if speedo worked (hasn't been in a running car for probably 20 years) if i run the drill motor in reverse, the speedometer registers up to 30-40mph pretty smoothly, but beyond that it jumps up and down, and sounds like gears inside are making noise (like they are dry, or even metal on metal noise)

is there a way to take speedometer apart and clean or lube those gears? Rick

pokey1

Corvette Central can rebuild your speedometer. Its not cheap, but its cheaper than a new one.

7T1vette

Put some graphite lube on the cable and try it again. The cable will work fine when dry, until it starts to bind/whip. If the speedo runs smooth at 30 mph, I doubt that the gears in the speedo are the problem.

Dustup7T2

I had a similar experience but with the mech tach. Was stable for ages then began bouncing when upshifting. After approximately a month of weekend driving (around 500 mi), the tach needle stopped sweeping during a drive (fell to zero while running) and didn't move anymore. No drama of a slow death like in the movies, it just failed to sweep anymore. Kaput.

Fixed it with a new catalog replacement. About 3 months of good operation later, the cable tang broke at the distributor. Installed new cable and has been rock solid since.

Not sayin' you'll have the same result but it may be something to consider. Oh, and I used powdered graphite. The Service Manual procedure (drawing cable through greasy palm) looked messy so I just dusted the extracted cable on reinsertion.

BTW: ordered a new cable assembly as I did not have access to a local service provider to make a replacement factory length. Good thing too, on comparison, found new cable was approx 2" longer than factory sheath. Went diving under the dash again to remove/replace. PITA but I've been under there several times and comfortable in reassembly.

I've been told that the lube works it's way to the head gears. I dunno, I can't see up there but my tach is steady as she goes.

Being that the two instruments are similar in operation, thought you might consider the return on your time and money. Good luck and hope you nail it.

razman

i'll try lubing the cable, i guess even new cables should be lubed before installation? the other problem is getting the new cable through the new firewall grommet! i have already made four cuts in the center rubber area, but still unable to push the smaller end of the cable through the hole! do i have to actually cut a line completely through the grommet, metal perimeter and all? Rick