O.K. Here is the FAQ page for speedometer repair. We have tried to answer the questions that people ask us most. An FAQ page is a living thing and we will add to it regularly. We hope you'll find answers here that will help. There may be some questions that you think are too dumb to ask. Go ahead and ask us. You may just think our answer is dumb.
(Q) My speedometer needle bounces, what's wrong?
(A) If there's no noise accompanying the bouncing it's likely that your speedometer cable has been kinked. The only cure for that is a new cable.
"Bouncing" can also be caused by the speedometer head drying out. When a speedometer is assembled or repaired, they usually put a drop of oil on the bearings. If this oil gets old and gummy or collects a lot of dust it will cause the bouncing you describe.
(Q) My speedometer makes a whirring noise, is it ready to wear out?
(A) Maybe yes, maybe no. That "whirring" sound is usually caused by a dry cable. You can detach the cable casing at the transmission end and carefully pull the cable through. Clean it with solvent and let it thoroughly dry then grease the length of the cable with a non-migrating grease, preferrably lithium-based. Then feed the cable back through. DON'T FORCE IT! The last inch or so you will have to turn the cable a little so that it will line up with the speedometer. Reconnect everything and test drive it. If that didn't cure your problem then the speedometer head likely needs service.
(Q) My speedometer seems slow, how can I check it?
(A) If you have changed to larger tires or changed your transmission or rear-end it will affect the speedometer reading. That can be a real shock when you think you're driving the speed limit and a state trooper is right behind you.
You can check the speedometer drive ratio by comparing it to the mile markers on most interstates. Or you can request a copy of our Odometer Calibration Form. It guides you through checking an odometer in a long driveway or parking lot.
A minor error can usually be corrected by changing the driven gear at the transmission end of your speedometer cable. If that won't work, we can build you a ratio adapter.
If your odometer checks out close to right (within 5 to 8%) then the speedometer magnet has lost its power. You need to take the speedometer in to a speedometer shop where they can usually recharge the magnet and service your speedometer.
If you don't have a shop near you, send it in to us. We will check it out and let you know what needs to be done. We won't do anything that will cost you money until we talk to you and get your approval.
(Q) What is a Ratio Adapter?
(A) A ratio adapter is a small box that has select gear sets installed that will increase or decrease the rotation speed of the speedometer cable. The gears come in sets to make specific corrections, and must be assembled by a speedometer shop. Well, actually you could assemble one yourself if you had about a hundred gears to choose from and knew which ones would make which corrections. It's just a lot easier to have a speedometer shop do it.
(Q) My speedometer works but my odometer quit. What happened?
(A) Probably one of the odometer gears is broken. These are short plastic shafts with a worm gear on one end and a helical gear on the other. German cars are notorious for this. German engineers just don't seem to want to adjust for U.S. temperatures and air quality. The fix for that is to take the speedometer apart and replace the gear. Take to to your local speedometer shop, it shouldn't be a big deal.
(Q) I got an instrument cluster from a wrecking yard. Will you change the odometer to read right?
(A) Only with a written work order from an established auto or truck repair shop. It must explain specifically what work is to be done and what the odometer reading is to be. Even then we reserve the right to refuse to reset odometers. It is a felony in most states to tamper with odometer readings, we're not willing to risk it for the sake of providing you with a counterfeit "low mileage" car -- no matter how nice you are.
(Q) Will you sell me the parts to fix my speedometer?
(A) Only if you are a registered speedometer shop. Manufacturers will not allow us to sell speedometer repair parts to the general public, sorry. In truth, we would not sell them even if the manufacturers allowed it. We just do not believe in it, although there is good money in repairing speedometers that have been broken by do-it-yourselfers trying to change odo readings.
E-mail us a request for a "Speedometer Shop Registration Form" and we'll send you one to see if you qualify.
(Q) I am putting a small block Chevrolet engine into my '40 Chev business coupe. Can I use the old gauges? How about my '38 Packard?
(A) You can use the old speedometer and fuel gauge. The amp gauges doesn't tell you much with an alternator and most car builders don't like running all of the current through the dash, they'd rather have a voltmeter. The temperature and oil pressure gauges on that car were Bourdon tube type and nearly impossible to recalibrate to the requirements of a late model engine.
We build a new gauge cluster with aviation standard electric movements, calibrated for the new engine: 250 degree temp gauge, 0 - 80 oil pressure, voltmeter, fuel gauge and a 120 mph speedometer. The graphics are faithful to the original but with new numbers to suit the new movements.
Yeah, we can do the same for the Packard. But we'll probably cry.
(Q) I have a great looking clock on my 46 Merc. Can you make it work again?
(A) Sure we can. We can do even better than that. If you like, we can replace the old movement with a quartz movement and keep your stock dial. On 46 Mercury the numbers are on the lens, we can refresh that for you, too.
(Q) I have a 71 Olds and the cruise control transducer broke and my speedometer stopped working. Can I bypass the cruise control unit?
(A) There are several ways to do this. We can make you a longer speedometer cable, or we make a bypass unit that just bolts on in place of the transducer. But the best way is to fix the cruise control. We make remanufactured AC transducers that sell for around $79 plus core, depending on model. If the vacuum servo leaks we have repair kits for that, too.
United Speedometer Service
Ship To: PO BOX 51957, Riverside, CA 92507
Phone (951) 742-7117 Fax (951) 742-7113
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