I'm glad you asked this question. I have an old one I'd like to lube but am afraid some one is going to tell you that you have to take it apart to do it. Tim
Just remove the CABLE from the shielded housing, clean it, dry it and apply "cable ease". Re install, drive. Don't lube the meter it self.
i went through three SW gages one stopped at 1 thousand miles the next "flickered" when they were acting up i thought the only way to lube them was to drill a hole in the housing to squirt some wd in.
That Stewart Warner speedometer is the one with the plastic frame made in Mexico, sorry to say that they are junk. Lubrication will not cure what ails it. You can try a few drops of sewing machine oil or mineral oil on the bushing, but I don't think it will do any good. Sent from my SAMSUNG-SM-G890A using The H.A.M.B. mobile app
I see we have a professional on board. I am going to ask because I don't know, do speedo's have some sort of bearing or bushing inside for the odometer to "ride" in and the speed needle as well? 33anda3rd is eluding to the problem I've had. Use an old speedo and they will begin to talk to you or break.
The speedometer cable spins the magnet (also called the first worm gear). The second gear runs horizontal and is turned by a worm gear on the shaft of the magnet. The second gear then turns a vertical third gear that turns a gear on the odometer. The odometer is supported on both sides of the frame through the center shaft that runs through the center of the odometer wheels. Odometers will lock up some times when rolling over multiple same digits, most often 9's or 0's. Since the odometer is the last link (gear) in the chain it can cause the magnet ( first worm) to strip, or break the cable. The speedometer needle is pressed on the shaft that is attached to the speed cup. In the center of the magnet there is a small bushing called the jewel (like a watch jewel). There is also an upper jewel that supports the speed cup shaft just behind the speedometer needle. When the cable spins the magnet turns inside the speed cup creating an eddy current that moves the floating speed cup thus moving the speedometer needle. Calibration is controlled by the strength of magnetism in the magnet which controls the eddy current that moves the speed cup. The stronger the magnetism the faster the response of the speed cup. Needle bounce or fluctuations happen when the jewel in the magnet that supports the floating speed cup is dry or becomes worn. If the jewel is dry and not worn it can be oiled but the speedometer has to be disassembled to oil the jewel. When the cup is separated from around the magnet you loose some of the magnetism so the magnet will need to be recharged then de-magnetized while the speedometer is spinning on the test bench to get the calibration correct. Most early speedometers have an oil wick hole that will let you lubricate the magnet shaft, this will quiet some noise but not cure needle bounce due to a worn or dry jewel. I know this was a long winded reply but I hope it helps explain some of how the speedometer works. Sent from my SAMSUNG-SM-G890A using The H.A.M.B. mobile app
It can also be caused by a dry or limber (worn) cable. Bouncing below 35 mph is usually cable, bounce or wide fluctuations above 35 mph is usually due to the speedometer being worn, in need of repair. Sent from my SAMSUNG-SM-G890A using The H.A.M.B. mobile app
Do factory speedometers operate the same way? The one in my 1948 Mercury made a noise so I unplugged it. Sent from my iPhone using The H.A.M.B. mobile app
Yes they do. If it's making noise and the needle is bouncing it's best to unhook the cable, if the jewel is worn and the speed cup is dragging on the magnet it will peg and break the needle or the speed cup shaft. Sent from my SAMSUNG-SM-G890A using The H.A.M.B. mobile app
Long time ago when I worked at a local Ford dealer I fixed several bouncing speedos by first removing the cable from the housing, clean and dry as already suggested, then inspect both ends of the cable for 'wiskers' or where the cable looked frayed. This can be cleaned with a file to square the ends. Then lube the cable and re install. I was surprised how many needed this. I'm talking of '60's and early '70's Fords but it should apply to any cable driven speedo. This is not to say any other comments are not true. Just easier to try the simple fix first.
I had trouble with some of my new SW gauges and I talked to a SW rep at the street rod nats. He said they are made in Mexico and he can't do anything for me. Told me to contact the company I bought them from. Well I'm done with SW, end of story
first SW speedo miles stopped at 67 miles, called Summit they sent a new one out, speedo needel jumped at all speeds, called Summit they sent a new one out, I almost installed this one with velcro but I decided to give SW one more try, well this was the best one the milage stopped at exactly 2000 miles. After 6 mouths I had had it SW, Called summit told them I waned to send this 5 gauge kit junk back to them for credit and and get a classic instrument kit and they did no problem. I got SW because back in the day they had a good reputation now they make junk made in Mexico.
e1956v, Thank you for the explanation. I always wondered how they worked. Good to know before I get a bug up my butt to some day take one apart & risk making it worse than it is. It's probably best to send one in for repairs. It would be money well spent. Bill
Wow. this had been a very informative thread. Glad to have learned all this. Thanks again to shoebox.
I had e1956v (Rusty) repair an old SW Police Special for me last summer. Dropped it off at his Colorado Springs shop on the way to Bonneville with a Pikes Peak layover. Got the 5 cent tour of his shop - really cool - well sorted - with all available horizontal surfaces filled with vintage "stuff". It's a must see if you're in the area and Rusty is a stand up guy who knows his shit.
Now that I'm back at work on Monday I thought I would post a few pics of the repair I did on Ryan's Stewart Warner speedometer for his Ford Truck. The first is a pic of the speedo after teardown. You can see the frame with the second gear, the upper bridge which holds the upper jewel and speed cup and also supports the odometer. Also the magnet (first gear) and the third gear to the right of the magnet. The next pic is of the magnet with the worn jewel, and a new jewel next to the old so you can see the difference. Then the new jewel on a dime for some perspective on size. Next is a re-jeweling tool for removal and replacement of the jewel. Finally a pic of calibration on the test bench after re-assembly. Sorry the last one is out of order, its of re-charging the magnet on a Corvette tach using an old magneto charger and a pic of the same tach being de-magnetized on the bench to calibrate. Just a side note in the last pic of calibrating the tach, if you notice sitting on the top of the test bench is a WWII paratroopers wrist compass that was given to my dad by a dear friend of his. Dad used it to check North-South polarity on the speedometer magnets when they needed to be re-charged for calibration, my dad passed 27 years ago on Dec 13th. He would have been 101 this year. I feel him looking over my shoulder every time I use it to this day when I check polarity with his compass.
I lubed an old metal cased one by drilling a small hole in the back and then immersing it face up halfway in liquid WD overnight and then letting it drain for a day, it worked. Sent from my iPad using The H.A.M.B. mobile app
What Charlie Chops is saying in a "diplomatic" way is that I've got piles of shit all over the place and that I paid him 5 cents to take the tour of my shop! It was good to meet you guys and put a face to a avatar, I'm glad you came by to drop off the speedo in person.
Is the "plastic frame" you refer to the threaded black plastic around the shaft? Is the "bushing" the shaft that I refer to? So these are unrepairable? The "jewel" can't be replace, or is it not cost effective? Thanks Rusty for chiming in on my post and thanks for the avatar compliment. I grew up on the Little Rascals and Three Stooges.
I guess I'm lucky that mine made it to 10,008 miles before shitting the bed. My odometer is still working. The needle bounces at all speeds, more erratically at speeds above 45 mph. I already removed, inspected, cleaned, re-oiled and reinstalled the cable. When time permits I'll road test it. If I get lucky, swell. If that didn't fix it them I'll be shopping for a new speedo.
Yes the part where the speedometer cable threads on, the entire frame is including that is made of plastic and the speedometer is not repairable, believe me I have tried multiple times. You will just have to replace it. If you notice you have 3 consecutive 0's showing so I bet the odometer is locked up and causing a chain reaction including the needle bounce.
The tenths digit still rotates when I spin the shaft by hand. I wonder if I had three consecutive sevens if coins would have started falling from under the dash and bells and lights would have started going off. LOL!!!!
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