Defective stepdown speedometer

railknight

The speedometer stopped working while driving my '53 Super Wasp back from Dr. Doug's (after a much needed complete engine rebuild, king pins replaced, two windows replaced, fuel tank and radiator replaced, etc.,.....the repair list seemed endless).   About a little more than halfway between Shelbyville, IN and the Chicago area (about two hundred miles), the speedometer started making a nasty screaming noise along with the gauge needle bouncing.  It would disappear and everything functioned well until it would start again.  This intermittent problem finally ended with the speedometer and odometer quitting all together.  Then, just a faint clicking noise could be heard that would increase in tempo as the car drove faster.  A few days after getting the Super Wasp home, I removed the speedometer cable from underneath the dash and drove the car slowly.  At first the wire within the cable didn't turn.  When I pressed down on it, it began to spin and continued despite releasing it.  QUESTION:  based on the information here, which unit is in need of repair.  The speedometer cable, the speedometer gauge itself or perhaps both.  Anyone who's been "down this road" and has suggestions on what repairs may be needed is much appreciated.

Dan

Jon B

Sounds like what exactly what happened on my '37, several years ago.  I sent the speedo out for repair and haven't had any problems since they sent it back.  If the cable's turning (and the top fitting hasn't fallen off) the problem must lie with the speedo itself.  If you want to save money, you might look for a used speedometer instead of paying to have this one fixed, but make sure it's properly lubed before installing.

Lance

Sounds like a speedo membrane gave way in the speedo cable sheath. A new membrane and a little graphite  and you're in business.      

railknight

Not familiar with the speedo membrane.  Where's it located?

Jay_G

I have had a similar problem in the past.  First is to identify if it is the cable or speedo.  I disconnected the cable and drove around the block trying to stop the cable from turning.  If you can stop the cable with your fingers or if it makes noise, there is the problem.  If the cable is silent and you cant stop the shaft it is the head. 

If it is the head, remove from car and depending on your level of adventure take it apart or send it off.  Usually it just needs to be lubed.  But if things won't turn smoothly by hand with a little bit of light oil.  Time to send off or find a another.  

Jay

railknight

Jay, I pretty much did the same thing you did and that was to disconnect the cable or sheath and see if the cable inside would turn as I drove.  I did notice, however, that I was able to pull the cable out of the sheath, about six inches, with no problem and simply push it back.  Doug Wildrick suggested I try to lubricate the gauge itself by applying some ATF transmission fluid to the cup or wick behind the gauge.  That may loosen things up to make the speedometer functional again.  I hope that's the case, because removal of the gauge doesn't look like an easy job!

Dan

Lance

railknight said:

Not familiar with the speedo membrane.  Where's it located?

The membrane is the slimey part of the cable that goes inside the sheath. Please use graphite when relubricating.    Petroleum products can gum up or get thick during cold weather .It's about the only area a liquid type graphite is used on a Hudson except possibly the door locks.

railknight

Is this the same graphite lubricant as used on home door locks?  If that's the case, I have a can of that graphite oil.

Lance

That should work. Be generous with it.

Kdancy

Graphited Penetrating Oil
http://www.kanolabs.com/penLub.html#anchor176254
Highly recommend their products.

railknight

Thanks for the Kano graphite oil recommendation.  I presently have a few cans of their penetrating oil.
Dan

railknight

Much to my surprise (and delight!), simply using a graphite based oil to lubricate the speedometer cable and ATF transmission oil to lube the speedometer itself did the trick.  Speedometer is nice and quiet and no more bouncing of the needle.  Getting oil into the oil cup behind the speedometer itself was the most challenging at first.  But, I found a rather simple means of getting a decent amount of oil to the speedometer.  I used a very small vintage sewing machine oil can that I have.  It's about 2 inches tall counting the can and spout.  This easily fits into one hand.  I put the oil can into my left hand, reached up under the dashboard and used my fingers to follow the speedometer sheath/cable to the rear of the speedometer.  Then I just used my index finger to lead the spout into the speedometer oil cup.  With slight hand pressure keeping the spout in the cup, I then pressed the bottom of the can and shot a small amount of ATF into the cup.  I followed this with a paper towel to wipe a trace amount of overflow (I also put down some newspaper on the floor to catch any possible drops so it didn't stain the carpet).  There are numerous sewing machine oil cans for sale at places like flea markets, antique shops and online auction sights like eBay selling from $5.00 to $15.00.  Anyway, thought I'd pass this information along.

Dan

 

Ol racer

Real Good Info: Thanks