D 24 Speedometer Question

[windsor8]

Anyone with experience working on a D 24 speedometer? Mine works ok up to about 30mph. As speed increases it starts to sound like its going to self destruct and the needle pegs and jumps all over. Any drawings of its innards or cleaning suggestion?

[greg g]

most likely a gummed up and sticky cable. Also there is a lubrication point on the rear near the cable retaining nut. Some light machine oil goes into a small reservoir that hols a wick that lubricates the needle.

The cable removes from the inside, just unscrew the retaiing ring, and pull the cable housing off the rear of the soeedo housing. Then after protecting your upholstery and carpet, pull the worm out of the cable assembly.

Clean it with a mild solvent, them lube it with a graphite based lub or white litium, and reinsert it. Then reattach to the speedo housing. In 90% of cases this procedure will take care of the noise ad jumping needle.

[windsor8]

most likely a gummed up and sticky cable. Also there is a lubrication point on the rear near the cable retaining nut. Some light machine oil goes into a small reservoir that hols a wick that lubricates the needle.

The cable removes from the inside, just unscrew the retaiing ring, and pull the cable housing off the rear of the soeedo housing. Then after protecting your upholstery and carpet, pull the worm out of the cable assembly.

Clean it with a mild solvent, them lube it with a graphite based lub or white litium, and reinsert it. Then reattach to the speedo housing. In 90% of cases this procedure will take care of the noise ad jumping needle.

Thanks I'll give it a try.

Merry Christmas to you and your family.

[busycoupe]

My D-24 speedo was doing the same thing when I bought the car. Before I bought it, the car had sat for 10-15 years. I found out about the oiling cup on the back of the speedometer from a helpful forum member. I used a flexible Zoom spout oiler to put a couple of drops in it, after a day or 2 of soaking in my speedometer was cured.

Good Luck & Happy Holidays!

[BobT-47P15]

When you do pull the cable out, you can then see if it has rubbed on the

inside of the housing and created any frayed places on the cable. If so,

that could also be a source of noise.

It seems in the olden days, one was supposed to use graphite on a cable,

but many folks have used the aforementioned lithium grease.

If it quiets down and calms down with the needle, and you still don't

think it's accurate for speed, get someone in another car to help

check it. I usually get the Mrs to follow me and communicate with

the cell phones. I tell her how fast I'm going according to my

speedo, and she tells me how fast per her late model speedometer.

I know that, for the most part, mine is about 15 mph off.....fast.

So, if mine says "50", I'm only really doing 35.

[Don Coatney]

When you do pull the cable out, you can then see if it has rubbed on the

inside of the housing and created any frayed places on the cable. If so,

that could also be a source of noise.

It seems in the olden days, one was supposed to use graphite on a cable,

but many folks have used the aforementioned lithium grease.

If it quiets down and calms down with the needle, and you still don't

think it's accurate for speed, get someone in another car to help

check it. I usually get the Mrs to follow me and communicate with

the cell phones. I tell her how fast I'm going according to my

speedo, and she tells me how fast per her late model speedometer.

I know that, for the most part, mine is about 15 mph off.....fast.

So, if mine says "50", I'm only really doing 35.

A GPS works better for speedometer calibration. It is more accurtate than my truck speedometer and it also records how many miles you have driven. I never go on a road trip without my GPS.

[cwcars88]

If your speedometer is off it may also be from a change in tire size.