speedometer (not cable)

[shaldaya]

is it common for the speedometer in the cluster to have problems in the 89?
both me and my brother have speedo issues in our 89 (his read 5 mph fast)

I have used lubricant on the cable, and I have replaced the cable, and neither did anything so I know its not the cable.
but while going about 70-80 mph, the speedometer starts reading high (by +20-30), and I swear I can hear the speedometer rubbing on something, and occasionally it will drop back down to my actual speed (educated guess based on rpm), and the rubbing sound goes away when it does
does anyone have any idea what could cause this issue?

 

[rubydist]

In the head of the speedo, there is a little wheel that rotates at the speed of the cable. Surrounding that is the arm with the speedometer needle. This arm/needle is spring loaded to return it to zero. The wheel and arm have magnets in them such that as you spin the cable faster, you generate more force to overcome the return spring to move the needle.

In your case, if you are hearing a rubbing noise, that means that a bushing inside the speedo head is worn out, allowing the little wheel to actually rub on the arm housing, which of course makes it read incorrectly. Its been a while since I was inside one of those clusters, but I don't recall that you can actually repair that bushing area - I think you should just replace the instrument cluster.

 

[luigisho]

rubydist post sounds correct to me also. I can not remember a post over many years where the cluster gauge was successfully repaired when the speedo failed internally. Cable yes, vss,easy but I can't for the life of me recall an internal gauge repair. Doesn't mean it can't be done, but I can't recall anyone ever doing it with this car.

 

[shaldaya]

In the head of the speedo, there is a little wheel that rotates at the speed of the cable. Surrounding that is the arm with the speedometer needle. This arm/needle is spring loaded to return it to zero. The wheel and arm have magnets in them such that as you spin the cable faster, you generate more force to overcome the return spring to move the needle.

In your case, if you are hearing a rubbing noise, that means that a bushing inside the speedo head is worn out, allowing the little wheel to actually rub on the arm housing, which of course makes it read incorrectly. Its been a while since I was inside one of those clusters, but I don't recall that you can actually repair that bushing area - I think you should just replace the instrument cluster.

what is annoying is I have several clusters, but none for an 89. do you think I could pull out the speedo from one and install it into mine?

 

[Greg Corcoran]

I can not remember a post over many years where the cluster gauge was successfully repaired when the speedo failed internally.

If you are near a large city there may still be a speedometer repair shop. I've taken several non SHO speedos to the one in Denver over the years and they've worked miracles for a fairly reasonable price. Some national instrument repair outfits also advertise in Hemmings.

 

[kwforddude]

Is there any Ford publications, manuals or literature published on speedometer repair?