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Time to go shopping for a more appropriate speedometer cable drive pinion?

Combined with the oversized tires, the problem with the speedometers is that as they age, the magnets in the spinning mechanism in the gauge get weaker. How that would affect the odometer, I don't know.

So, perhaps you're right. The replacement cable I put in was probably not totally correct????

West, if I remember my high school auto shop instruction correctly (which was more than a half-century ago) the odometer and speedometer functions are not internally linked. That is, a speedometer error does not necessarily translate into an odometer error. I think the proof is that in a car with a completely inoperative speedometer, the odometer can continues to function. If I have this wrong, someone please come along and correct me, it's an interesting point.

Apparently, correcting or adjusting the magnetism for the speedo isn't a big deal; when I had my 34 speedo (a Waltham) repaired some years ago by Reynolds, it came back with a calibration certificate and was +/- 1 or 2 mph of true all the way thru it's range. PS - I suppose this has it's limits and isn't the way to adjust for incorrect speedo pinion gear matched to the rear axle ration.

Well that is true, something like undersized/oversized tires would affect both the speedo and odometer readings.

The odometer is driven directly by the speedometer cable (through gears).

The needle of the speedometer is driven indirectly by a rotating magnetic field created by a permanent magnet that's driven off same cable.

Tweaking the speedo calibration is not the proper solution for incorrect drive/driven gears at the transmission or changing tire size or axle ratio, etc.

When an appropriate ratio couldn't be achieved by swapping out the drive/driven gears for the transmission, there used be inline adapters that could be installed at the trans end of the cable, but they didn't come cheap - even back then.

something like undersized/oversized tires would affect both the speedo and odometer readings.

For sure.

I just replaced my upper outer shock mount bushings. I did this a couple of years ago and the original bushings were nearly perfect. The only reason I replaced them was because the pin and sleeve were rusted together and I had to cut them off. Now these two-year-old bushings are nearly distintigrated. Is the modern rubber being used inferior? Is there something I'm doing wrong?

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Dear West:

I think there are a few ways this could happen:

a) The upper control arms should be tightened with the suspension fully loaded at ride height level. This can be achieved by setting the hub on a jack stand at proper ride height using the lugs as the load bearing members. The bushings twist with movement and if they are tightened with the suspension hanging then when the car sits level they are already twisted and will twist beyond limits when the car hits a bump.

b) The rubber parts are too small for the hole. I assume you purchased the items from an established supplier. Once I contacted a supplier with a question about the proper way to install some Packard suspension bushings because the manual said the bushings were not intended to be replaced. They referred me to someone who - after I got past the insults as to my ability - answered my question.

c) A tire is way out of balance concurrent with a worn out shock. This would cause suspension drumming and beat the bushings to pieces. I don't think this is your problem.

If the parts went together without a lot of effort, perhaps they aren't correct. I'll wager that if you had OEM parts you might have to use a press to get them into the suspension because of the hysteresis required for the load bearing rubber to function properly.

I don't think this can be caused by an alignment problem unless the car was spun around into a curb. Don't laugh, a lot of Packards aren't very good in the snow and I've seen this on Packard V-12s.

Unfortunately, OEM parts are non-existent, but maybe someone has one that can be used to compare the new with original.

Good luck with your car.

Tim
Thank you for your thoughts. After sleeping on it, I think that your answer "a" is partially correct.

There is no way that you can install the pin while the wheel is hanging. The shock arm wants to push down, so I put the jack stand on the "A" arm to lift it. I suspect that what I should have done is install the pin, then raise the car so that the wheel drops down, releiving the stress on the lower part of bushing. Revisit time, before I take off for Hershey.

Shocks rebuilt by Five Points, however last night I noticed one of them was fairly low on juice. No sign of leaks, and I don't remember checking the level when I got them back.

No alighment problem. Realigned when I replaced outer tie-rod ends. I've driven 7,000 miles and no odd tire wear, and no pull in either direction

No vibration or shake in the steering wheel

My other thought is that the modern rubber material is no where near to specifications of what the original was.

Nevermind. I just realized (was informed) that the shock itself does not apply any pressure until "shocked" in one direction or another. Since I had the jack stand positioned so that there was no downward or upward pressure on the wheel, it should be installed properly.

I'll keep an eye on the bushing and keep you updated.