lower intake manifold

[pittsbfan2000]

I was replacing all the gaskets on my lower and upper intake manifold and ran into a problem. After installing the lower gasket, then installing the lower intake to the engine block, there are 8 bolts. the following are the specs for the torque on tightening them.

Using the guide pins, install the intake manifold. Tighten the bolts in sequence in four steps.
1 Tighten to 2.5 Nm (22 inch lbs.) .
2 Tighten to 10 Nm (88 inch lbs.) .
3 Tighten to 13 Nm (115 inch lbs.) .
4 Tighten to 14-18 Nm (11-13 ft. lbs.)

so i started by doing all 8 bolts at 22lb, then i was attempting to do the second step at 88lb, and when i was doing bolt #1 it snapped.....

I do not under stand the above steps, why would you tighten them from 22 to 88 to 115 then 11-13? Why do step #4?

I'm also trying to figure out why the bolt broke? It broke around 40 - 45 lbs

Are you suppose to use brand new bolts?

Any suggestions would be appreciated..

[pittsbfan2000]

Forgot to mention this is on a 99 Explorer OHV