Speedometer Repair
 

On the 52 Mercury the speedometer and odometer has not worked in close to 50 years. Permanently stuck on 120 mph and 82 something thousand miles. The disconnected cable turns just fine at the top end so I'm wondering if I could/should try getting into the instrument panel to clean and lube the speedometer in hopes that is all it needs. Just removing the dash I can see what appear to be hold down screws all around the perimeter at the back. Would removing these give me access to the odometer/speedometer? Or should I just leave it alone before I do further damage. This photo shows the back side of the panel.

Re: Speedometer Repair
 

You can certainly attempt to repair this yourself. A thorough cleaning and light oiling often do the trick.
As an "option" I'd suggest sending it to a friend of mine, Mike Blaisdell. He does this repair professionally. He's a very ethical fellow and does great work. He also does it in a very timely fashion. A typical "rebuild" with calibration is about $100.

Re: Speedometer Repair
 

.......or, ya can ALWAYS brag that it looks like it's goin' 120 MPH just sittin' there.......PRICELESS! DD

Re: Speedometer Repair
 

Will he do a '40 standard speedometer, bezel and instrument panel restoration?

Re: Speedometer Repair
 

I had very good work with a quick turn around from Bob's Speedometer
www.bobsspeedometer.com 10123 Bergin Rd. Howell, MI 48843
Call and talk to a tech and they will give a free estimate. They rebuilt my speedo 3 years ago and it is working just fine. Not a sales pitch, just a suggestion.

Re: Speedometer Repair
 

He (Mike) doesn't do the cosmetics... only the mechanisms. He's done a number of '40 Ford speedos for me.

Re: Speedometer Repair
 

I had done some searching on this forum a while back and saw several threads on disassembly and repair. I was hoping there might be a youtube video or something to give a few clues. If I have to remove it from the car to send away I might as well attempt opening it up myself and trying to clean and lube first in hopes that is all it needs.

Re: Speedometer Repair
 

The speedometer will have two screws that hold it in the housing, from what I can see the face of the cluster may have to be taken off to get to the screws if they are holding it from the front, the speedometer should just come out so you can clean it, it is always good to take out the gears and clean the inside as well as the gears and then lubricate with a light oil. I have done many speedometers, but I have never done one for a 52 mercury.

I hope this will help.
BILL WELLS
bobwellsnoveltyshop

Re: Speedometer Repair
 

Thanks Bill. Every bit of information may help me figure out how to disassemble safely. I need to take better pictures but this one shows the back of the speedometer where the cable attaches. Appears to be 2 screws holding something at that point.

Re: Speedometer Repair
 

Hello, what ever you do, do not take apart the drum and magnet assembly. It's been my experience that once that assembly is tampered with the magnet will have to be re-energized/calibraded. Tom

Re: Speedometer Repair
 

Thank you Mike.

Re: Speedometer Repair
 

OK, First off I am not familiar with your Merc gauges but most of the speedometers are very sim to one another. I believe that the two screws hold the actual guts of the speedometer in the metal case. You will probably need to get to the front of the speedometer somehow first, and then remove the two screws on the back. I have reworked my '38 speedo by removing the glass and bezel and then removing the two screws and the whole mechanism (face and all) then pulls out of the case. Gently clean it up and look it over but dont get crazy and pull anything apart yet. Hook up a cable in a drill and spin the speedometer and watch to see what it does. If you can not see whats wrong probably time to bite the bullet and send it in.

Re: Speedometer Repair
 

Somewhere on line, there may be some general break downs of speedometer type instruments. The drive cable enters a slot in the internal magnet drive shaft of the unit. The magnet rotates inside of an iron or steel cup but is not physically attached to it. The cup has its own support bearings and a sensitive clock type spiral wound spring that provides force against rotation with the speed needle attached to the outer end of this cup shaft. The faster the magnet spins inside the cup, the farther the cup pulls on the spring in rotation which is calibrated to give the speed indication on the indicator dial.

If the drag cup shaft bearings wear out, the cup can move far enough over to stick to the rotating magnet. This makes the indicator needle peg out and a lot of noise is created by the metal to magnet contact inside the instrument case. If just the drag cup spring breaks, the needle will peg but there won't be a lot of noise. A person would have to either find a good speedo for parts to repair the old one or just use the other speedo if in good shape and properly serviced. The odometer wheels can be reset if need be to match the original mileage or a person can zero them out. The odometer system is just a mechanical set of gears and blockers and is relatively simple. Some number decal sets are available for the wheels. If the face has numbers on it and not the outer lens, some shops can silk screen the numbers back on. Most shops are set up for the more popular cars & brands but may not be set up for all units out there. There were variations in FoMoCo production due to different vendors for parts and such so you sometimes have to settle for what ever is available. The more work a shop has to do, the more they will charge to do the job so it pays to go with a reputable shop. If you tell them what you have and ask a lot of questions, a good proprietor should be able to answer most of your questions.

I've repaired a lot of the Stewart Warner speedometers for the different motorcycles that used them since there are some parts available but I haven't worked on the Ford/Mercury ones for my 51s. I did buy a good used one for one of them so I just wrote down the mileage when I installed it so I can keep track. The old one was broken up pretty badly so no telling how much mileage was on that car anyway.