CAT C12 specs/repair manual?

I don’t have a CAT engine, but I’ve gotten my manuals from a site called MyPowerManual. There were cheap. I see there are 2 or maybe 3 manuals, depending on your engine serial number. But before you buy anything, try to find them online for free.

Aside from the engine manuals, there might be a manual from your truck manufacturer. Try to find that one online too.

The last method for getting torque specs is to use bolt torque spec charts. Now, this requires to be able to determine the bolt grade/strength, thread diameter, and thread pitch. It’s confusing to learn about these things at first, but with the help of YouTube you can master it. You’ll want to buy a manual caliper (or a good quality digital one) and also some thread pitch gauges for both standard and metric.

 

1/4" -- 9 ft lbs (+or- 2)
5/16" -- 18 ft lbs (+or- 4)
3/8" -- 35 ft lbs (+or- 7)
7/16" -- 50 ft lbs (+or- 11)
1/2" -- 75 ft lbs (+or- 15)
9/16" -- 120 ft lbs (+or-22
I did a little work on my C-15 and needed the manual for it. I found a CD on eBay and it was a digital version of the hardcopy. It has all of the torque specs, part numbers and disassembly/assembly instructions, with illustrations. I do not recall the name of the place I bought it from, but do a search and I am sure it will be out there.

 

I mentioned in another thread but CAT generally doesn't list a spec for every single fastner on everything they build. If CAT doesn't list a torque spec in the procedure or under "specifications" or "special instruction" its generally understood that the fastner is torqued by size/grade according to the bolt torque chart.

In all honesty, I rarely break out the torque wrench unless its for something critical like main/rod caps, exhaust manifold, head bolts etc.

 

I compared the torque spec list you posted for standard bolts, and they appear to match grade 8 (strength) bolts with the thread pitch number on the higher side. Personally, I’d go a little lower than the torque spec numbers on the chart below. It’s coming from a Cascadia workshop manual. The three charts are for standard size lubricated and unlubricated threads and also metric size lubricated threads.

 

Some food for thought:

When a torque spec says "X" lb-ft plus/minus "Y" lb-ft, set it to the number given as the plus/minus is a margin of error for torque wrench accuracy.