Im having Speedometer issues!! HELP!!

[1970K10NamedCrunch]

Hello. So, I am having some issues with my speedometer. When I'm driving, it works fine till i get to 35mph. And it stops. It stays at 35 mph.. Then I slow down, and it comes down to about 23mph, and it sticks there. I have to tap the speedometer to get the needle to drop. The whole gauge cluster is original, other than Water Temp.. And the speedo has a new cable, just oiled a few weeks ago, and that didnt help either.. So what could possibly be the issue? I need help. PLEASE!! I pulled the instrument panel out of the dash, and the oil pressure gauge wouldnt come out of the back of the o.p. gauge.. But i also didnt drop the steering column either, so maybe that will fix the Oil Pressure gauge. Please help!! Any advice or suggestions would be much appreciated. Thanks.

[Daddy Brim]

Did you remove the hard line on the back of the oil pressure gauge? Also you should not have to drop your steering column to get the instrument cluster out. I have no idea on the speedometer, but you can get a used one on the parts board cheep.

[1970K10NamedCrunch]

I unscrewed the nut off the back of the oil pressure gauge, but the line would not co me out. And my dad told me that i could possibly get at it easier if i dropped the steering column because it would give me more room.

[1970K10NamedCrunch]

Also, i cant get to my speedo, with out removing the gauge cluster.. and the oil pressure line is the only thing holding me back. I would like to get my speedo fixed if i can. Its hard to find a speedo that says 75,286 original miles on it. haha

[StoningtonQB]

You should do some Googling. Changing the odometer on these trucks is a walk in the park. And check out LMC truck for a reproduction speedometer.

[1970K10NamedCrunch]

Ive been searching all over google, and cant find nothing. thats why i joined this site to see if anyone could help haha ive looked at lmc, and thought about it, but again, i need to get the line off of my oil pressure gauge somehow. its a steel line going into it, and it wont come out.

[Daddy Brim]

If you have taken the nut that holds the oil pressure line on the back of the gauge off, the line should just pull out. May be your line is stuck and it just needs a good yank to get it out. It should not be that hard to get your cluster out.

[TobyArnot]

I have not been able to remove the cluster without dropping the steering column, either. I've done it enough times, I now can gather the hand-full of tools needed to do the job and I can do it fairly quickly.
I have the original speedo from my '70 C-10. It was working when I replaced the whole cluster. It's yours if you will pay for shipping. Don't know the mileage, but as I remember it was 90K +.

[1970K10NamedCrunch]

Thanks guys. Ive been worried about it. My speedometer is the only thing keeping me from driving my truck.

[Andy4639]

The cluster will come out a lot better if you drop the steering column. I have done mine so many times over the past 25 years I can do it in my sleep. You want scratch up the paint on the column either if you drop it. The oil line is held in place by the ferral fitting which maybe hung on the lip of the oil gauge. The cluster has to be unplugged and speed cable took loose for it to come out. I would look at greasing up the speedo it self once you have it out.

[1970K10NamedCrunch]

i was thinking that was the issue with my speedo, it needs to be lubed.

[1970K10NamedCrunch]

Another thing. Where exactly is the main wiring harness for the cluster that you have to disconnect to get the dash out? i cant see it under the dash, and my repair manual doesnt show anything about how to take the dash apart..

[Andy4639]

A couple of questions for you.

What nut did you take off? Is it brass are copper? If not you took the wrong nut off.

Look at your dash it has two flange nuts holding the headlights and wiper switches in place they will keep it from coming off as well. Needle nose pliers in the indentions will get them loose, they just unscrew. You have to get the knobs off thoe first.
PM sent.

[1970K10NamedCrunch]

i took the headlight and wiper knobs off and the rings. And my cluster is all stock and i know that theres only one line going into my o.p. gauge, and i took the nut off of it. but i think the line is stuck. i didnt have a whole lot of room to pull on the line, so i will drop the steering column and try it that way.

[Andy4639]

Originally Posted by 1970K10NamedCrunch

i took the headlight and wiper knobs off and the rings. And my cluster is all stock and i know that theres only one line going into my o.p. gauge, and i took the nut off of it. but i think the line is stuck. i didnt have a whole lot of room to pull on the line, so i will drop the steering column and try it that way.

OK good luck. you have my number if you need to ask anything.