1991 Bronco Speedometer wrong when cold

[hesher866]

On cold mornings, and especially during winter, my speedometer loses it. It says I'm going 75 when I'm really going about 35 to 40. It wobbles around and revs up like a tachometer when I accelerate. It always says I'm going way faster than I actually am. It is accurate when it is warmer towards the evening and it doesn't seem to be a problem during summer. Any ideas on what the problem might be? I'm hoping it's something relatively cheap. It's not a major problem but it bothers me and would like to fix it. If its an expensive fix, I'll leave it.

 

[tiller83]

Likely the grease in the housing is old and gummed up, when cold and stiff it sticks to the cable causing it to bind up and when it gets enough load it springs causing the spedo to race. This happens over and over. When the grease is warm enough, it alows the cable to move properly. Depending on your year and options as to if you have a 2-piece or single cable will vary the difficulty but other wise is a cheap fix. Disconnect spedo cable at t-case,pop retainer off spedo gear and remove gear(note how it is installed),remove gear and pull cable from housing. Clean cable with solvent,dry and reinstall-several times to clear old grease from housing. If you choose, and some models you must, pull the cable end from the spedo in the dash to remove the cable and flush the housing with brake cleaner. DO NOT put paper,rag or other type on the cable through the housing to clean. When satisfied with cleanliness or operation of cable, apply a coat of lythium grease or other stay soft grease to the cable and reassemble. If you feal preasure when insalling gear onto housing, spin gear untill cable seats, Remember it must seat into spedometer and into gear. Test drive and tell the wife how cleverly you fixed the old bronco for @ .50 cents, or $5 if you used the brake cleaner.

 

[hesher866]

Thanks for the advise. I'll be doing it soon. I'll post again when it works!