6 volt or 12 volt

May be a stupid question, but how do I know if I have a 6 volt or a 12 volt system. 1967 cj5
F-134 engine

And also is the 10 inch or 11 inch brake just a measurement of the diameter of the brake drum?

I just want to be sure on these things before I start ordering parts.

 

Does the battery have three cells (caps) or six? Six will be twelve volt.

If you have no battery I would try pulling a tail-light or headlight bulb and check for part numbers. For instance, a #1157 tail/brake bulb is a 12 volt. #1154 is six volt type

By 1967 I would expect the system to be 12 volt.

 

They made the switch in 56 1/2 to 12 volt as I recall. My 58 CJ has 12 but my 55 wagon has 6. So by 67, definately 12.

 

The battery is a 6 cell... so it's 12 volt... thank you!

 

Another one of the old when did Jeep do the changes. IIRC you could get a Jeep in the late '50s that could be 6 or 12 volt so yours is a 12 v system.
Yes, measure the inside of the drum.

 

The generator/altenator (if present) should have a data tag on it (if present) also, stating 6 or 12 volt.